Jian Li Arizona State University
Chung-Chih Wu National Taiwan University
Jian-Bin Xu The Chinese University of Hong Kong
NoraS. Radu E. I. DuPont de Nemours and Co., Inc.
AssangaB. Padmaperuma Pacific Northwest National Laboratory
E.I. DuPont de Nemours and Co Inc
OO1: Materials Design and Synthesis
Monday PM, April 25, 2011
Room 2016 (Moscone West)
10:00 AM - OO1.2
Long Oligofurans - Synthesis, Reactivity and Devices.
Michael Bendikov 1 Show Abstract
1 Department of Organic Chemistry, Weizmann Institute of Science, Rehovot Israel
Despite the diverse applications of organic electronic materials, only a limited number of families of these materials have been developed. Long α-oligothiophenes (particularly α-sexithiophene) and oligoacenes (particularly, pentacene) have been extensively studied. Yet, while oligothiophenes are intensively studied, their close analogs, long α-oligofurans were not known. In this lecture, I will discuss the synthesis and characterization of a series of long unsubstituted α-oligofurans (up to n=9).1 Interestingly, α-oligofurans are more fluorescent, exhibit better solid state packing, and show higher rigidity than oligothiophenes, and are more soluble than oligothiophenes. Additionally, unlike other popular oligomers in organic electronics, furans can be obtained from renewable resources, and furan contained materials should be biodegradable. Oligofurans show high field effect mobility, similar to oligothiophenes (up to 0.07 V cm-1 s-1) and high on/off ratio (10-6), which makes them attractive for future device applications. Finally, oligofurans show interesting selectivity in Diels-Alder cycloaddition, which is remarkably different from oligoacenes.
1 O. Gidron, Y. Diskin-Posner, and M. Bendikov, J. Am. Chem. Soc. 2010, 132, 2148-2150.Selected as a research highlight by Chemical & Engineering News, 2010, 88 (issue 7, February 15), 45; selected for highlighting in SYNFACTS 2010, 5, 0536, and research highlight (U. H. F. Bunz, α-Oligofurans: Molecules without a Twist, Angew. Chem., Int. Ed. Engl. 2010, 49, 5037–5040) based mostly on this paper.
10:15 AM - OO1.3
Perylendiimides and Naphthalenediimides in Alternating D-A-Polymers Comprising Cyclopentadithiazole.
Daniel Dolfen 1 2 , Kristina Schottler 1 2 , Jan Moritz Koenen 1 2 , Christof Kudla 1 2 , Dietrich Breusov 1 2 , Seyfullah Yilmaz 1 2 , Ullrich Scherf 1 2 Show Abstract
1 Macromolecular Chemistry, Bergische Universität Wuppertal, Wuppertal, NRW, Germany, 2 , Institut für Polymerforschung, Wuppertal, NRW, Germany
Conjugated donor-acceptor copolymers containing alternating electron-rich and electron-poor main-chain moieties are in the focus of research for many years. Nevertheless there is still an interest for new monomer combinations in order to match the specific requirements in the particular application field of polymeric semiconductors. By combination of strong acceptor with electron-rich aromatic building blocks like thiophene low-bandgap-polymers can be synthesised, which show promising properties as active material of organic solar cells (OSCs) or ambipolar organic field effect transistors (OFETs). Strong electron-withdrawing building blocks are arylene diimides like naphthalenediimide (NDI) or perylendiimide (PDI). Alternating copolymers containing NDI or PDI acceptors and the novel 7,7-dialkylated cyclopenta[1,2-d:4,3-d’]dithiazole (CPDTz), 4,4-dialkyl-cyclopenta[2,1-b:3,4-b’]dithiophene-2,6-diyl (CPDT), and benzo[1,2-b:3,4-b’]dithiophene (BDT) donor units have been prepared and their optical and electronic properties studied.
10:30 AM - OO1.4
Electron Accepting Dithiarubicene (Emeraldicene) and Derivatives Prepared by Unprecedented Nucleophilic Hydrogen Substitution by Alkyllithium Reagents.
Ali Reza Mohebbi 1 , Fred Wudl 1 Show Abstract
1 CNSI, UCSB, Santa Barbara, California, United States
Polycyclic aromatic hydrocarbons (PAHs) containing fully unsaturated five-membered rings, fused externally to six-membered rings, compounds such as fluoranthene, indeno[1,2,3-cd]-fluoranthene, rubicene and 9,9’bifluorenylidene (99’BF) have been the subject of intense study for past decades.[1,2] In addition to PAHs that are composed of carbon and hydrogen atoms only, polycyclic heteroaromatics (PHHs) such as, for instance dithiarubicene (emeraldicene), containing sulfur, nitrogen and oxygen heteroatoms are also known. Recently, these molecules, because of the extended π-electron structures, have received attention for their unusual (photo)-physical properties, e.g., anomalous fluorescence and high electron affinities. In particular, certain large PAHs play a significant role as materials for organic light-emitting diodes (OLEDs), field-effect transistors (OFET), photovoltaic cells, and sensors.Herein, we report our dramatic yield improvement and synthesis of some new disubstituted emeraldicenes (1) via a Pd-catalyzed reaction in CH3CN (Scheme 1). Moreover, an unusual, nucleophilic aromatic hydrogen displacement alkylation of emeraldicene by alkyllithium reagents produced highly soluble mono-substituted emeraldicene 2 (R = t-butyl) with a significant amount of π-stacking in the crystal (Figure 1).Emeraldicenes are of potential use as organic acceptors, in analogy to 99’BF.[4b] 1 2Scheme 1. Improved synthesis of 1 and its nucleophilic alkylation reaction. Figure 1. Crystallographic order of compounds 2 (R = -Me, -t-butyl).a) L. T. Scott, Pure Appl. Chem.1996, 68, 291-300; b) A. Necula, L. T. Scott, J. Anal. Appl. Pyrolysis 2000, 54, 65-87; c) L. W. Scott, H. E. Bronstein, D. V. Preda, R. B. M. Ansems, M. S. Bratcher, S. Hagen, Pure Appl. Chem. 1999, 71, 209-219; d) P. W. Rabideau, A. Sygula, Acc. Chem. Res. 1996, 29, 225-242. a) H. A. Wegner, L. T. Scott, M. Amin, J. Org. Chem. 2003, 68, 883-887; b) J. E. Rice, Y. W. Cai, J. Org. Chem. 1993, 58, 1415-1424; c) S. Pogodin, P. U. Biedermann, I. Agranat, J. Org. Chem 1997, 62, 2285-2287.a) M. Smet, R. Shukla, L. Fulop, W. Dehaen, Eur. J. Org. Chem. 1998, 2769-2773; b) M. Smet, V. J. Dijik, W. Dehaen, Tetrahedron 1999, 55, 7859-7874; c) M. Smet, V. J. Dijik, W. Dehaen, Synlett 1999, 4, 495-497.a) C. Goojjer, I. Koyin, N. H. Velthorst, M. Sarobe, L. W. Jenneskens, E. Vlietstra, J. Spectrochim. Acta. Part A 1998, 54, 1443-1449. ; b) F. G. Brunetti, X. Gong, M. Tong, A. J. Heeger, F. Wudl, Angew. Chem. Int. Ed. 2010, 49, 532-536.a) M. Bendikov, F. Wudl, D. F. Perepichka, Chem. Rev. 2004, 104, 4891-4945; b) J. E. Anthony, Chem. Rev. 2006, 106, 5028-5048; c) J. E. Anthony, Angew. Chem. Int. Ed. 2008, 47, 452-483.A. R. Mohebbi, F. Wudl, accepted. Chem. Eur. J. Cyclic voltammetry of emeraldicene shows it to be as good an acceptor as 99’BF.
10:45 AM - OO1.5
Facile Synthesis of Benzo[1,2-c;4,5-c’]bis[1,2,5]thiadiazole, [1,2,5]thiadiazolo[3,4-g]quinoxaline and Pyrazino[2,3-g]quinoxaline Derivatives: Bandgap and Spectra Engineering.
Teck Lip Tam 1 , Hairong Li 1 , Fengxia Wei 1 , Ke Jie Tan 1 , Christian Kloc 1 , Yeng Ming Lam 1 , Subodh Mhaisalkar 1 , Andrew Grimsdale 1 Show Abstract
1 Materials Science & Engineering, NTU, Singapore Singapore
In our recent papers, we have demonstrated one-pot synthesis of the dibromo derivatives of benzo[1,2-c;4,5-c’]bis[1,2,5]thiadiazole (BBT) using 1,2,4,5-tetraaminobenzene (TAB) as the precursor in good yield.1 This provides easy access to synthesize low bandgap materials based on this strong electron-withdrawing moiety, which would otherwise be tedious and hazardous if based on literature synthetic procedures. We have also showed the versatility of BBT by using it as a precursor to synthesize [1,2,5]thiadiazolo[3,4-g]quinoxaline (TQ) and pyrazino[2,3-g]quinoxaline (PQ) derivatives.2 This was again carried out in an one-pot reaction by selective reduction of the BBT moiety using iron or zinc in acetic acid, followed by addition of 1,2-diketone. Both TQ and PQ small molecules show interesting electronic structures alongside with their low bandgap and broad absorption spectra. The novel synthetic methodologies provide easier access to BBT, TQ and PQ derivatives, which can be incorporated into polymers for organic electronics application. Comparison between BBT, TQ and PQ small molecules will also be discussed.1.Tam, T. L.; Li, H.; Wei, F.; Tan, K. J.; Kloc, C.; Lam, Y. M.; Mhaisalkar, S. G.; Grimsdale, A. C., Org. Lett. 2010, 12, 3340-3343.2.Li, H.; Tam, T. L.; Lam, Y. M.; Mhaisalkar, S. G.; Grimsdale, A. C., Org. Lett. Submitted.
11:00 AM - OO1: MDS
Jian Li Arizona State University
Chung-Chih Wu National Taiwan University
Jian-Bin Xu The Chinese University of Hong Kong
NoraS. Radu E. I. DuPont de Nemours and Co., Inc.
AssangaB. Padmaperuma Pacific Northwest National Laboratory
OO10: Poster Session: OLED and Organic Solar Cells
Wednesday PM, April 27, 2011
Salons 7-9 (Marriott)
1:00 AM - OO10: Poster
OO10.20 Transferred to OO1.5 Show Abstract
1:00 AM - OO10: Poster
OO10.67 Transferred to OO17.12 Show Abstract
9:00 PM - OO10.1
Incorporation of Furan into Low Band-gap Polymers for Efficient Solar Cells.
Claire Woo 1 2 , Pierre Beaujuge 1 2 , Thomas Holcombe 1 , Olivia Lee 1 , Jean Frechet 1 2 Show Abstract
1 College of Chemistry, University of California, Berkeley, Berkeley, California, United States, 2 Materials Sciences Division, Lawrence Berkeley National Lab, Berkeley, California, United States
A survey of state-of-the-art organic solar cells reveals that all high performance polymers reported so far rely on thiophene or thiophene-based heterocycles. In contrast, there has been a scarcity of studies examining polymer backbones containing furans. This is surprising given that furans exhibit similar energy levels and a comparable degree of aromaticity relative to their thiophene counterparts. Here, we present the design, synthesis, and characterization of the first examples of furan-containing low band-gap polymers. We found that inserting furan moieties in the backbone of the conjugated polymers enables the use of relatively small solubilizing side chains because of the significant contribution of the furan rings to overall polymer solubility in common organic solvents. These low band-gap furan-containing polymers exhibit similar optical and electronic properties as their thiophene analogs, and they achieve up to 5% power conversion efficiencies in bulk heterojunction solar cells with soluble fullerene derivatives. These results demonstrate the potential of furans as thiophene alternatives in the design of high performing OPV materials.
9:00 PM - OO10.10
Multi-layer Blade Coating for Organic Light-emitting Diode and Solar Cell.
Meng Hsin-Fei 1 , Zan Hsiao Wen 1 Show Abstract
1 , National Chiao Tung University Institute of Physics, Hsinchu Taiwan
Multilayer organic light-emitting diodes are fabricated by blade coating without dissolution. A soluble polymer is used for hole transport layer. Both Ir complex with alkyl side chain and dendrimer are used the emitter. Efficient electron injection is realized by coating a small-molecule electron transport layer combined with the relatively stable evaporated LiF/Al cathode. The efficiency is 12 cd/A for blue emission, 45 cd/A for green, 20 cd/A for orange, and 17 cd/A for red. Large area OLED with brightness up to 8000 cd/m2 is made with blade coating. For solar cell blade coating is applied polymer blend in toluene. Power conversion efficiency of 4.6 % is achieved. Top-emitting OLED on metal substrate is made by blade coating. Silver with chemical modification to increase the workfunction is used as anode. Cathode can also be deposited without vacuum by printing chemically modified aluminum from epoxy mold.
9:00 PM - OO10.12
Charge Transport Enhancement via Air-mediated Self-organization in Polymer Semiconductors.
Takashi Kushida 1 , Takashi Nagase 2 3 , Hiroyoshi Naito 2 3 Show Abstract
1 Integrative Technology Research Institute, Teijin Limited, Hino, Tokyo, Japan, 2 Department of Physics and Electronics, Osaka Prefecture University, Sakai, Osaka, Japan, 3 The Research Institute for Molecular Electronic Devices, Osaka Prefecture University, Sakai, Osaka, Japan
Organic field-effect transistors (OFETs) fabricated on the basis of soluble organic semiconductors are attracting considerable attention as a key device for realizing printed electronics. In recent years, there has been a remarkable increase in the charge mobility in soluble organic semiconductors as a result of the improvements in intermolecular coupling utilizing self-organizing behaviour on hydrophobic, low-energy surfaces. In this study, we report a significant enhancement in the self-organization of soluble organic semiconductors in OFETs fabricated by microcontact printing (μCP) using polydimethylsiloxane (PDMS) exhibiting varying surface energy. The field-effect mobility measurement of a printed poly(3-hexylthiophene) (P3HT) thin film reveals a large difference between the microscopic structures of the P3HT thin film at the interfaces with air and with substrate; in addition, it was found that efficient charge transport through the microstructure was formed at the air interface. The charge mobility of P3HT FETs fabricated on bare SiO2 substrates by air-mediated self-organization is more than 100 times higher than that of P3HT FETs fabricated by spin coating. The charge mobility of P3HT FETs can be improved by enhancing the molecular ordering of P3HT molecules in a very thin layer at the air/P3HT interface that is responsible for superhydrophobic air. This improvement is also observed in the charge mobility of other organic semiconductor films prepared from solution processes. Thus, we conclude that the enhancement in the self-organization at the air/P3HT interface generally occurs in solution-processed organic semiconductors.Moreover, we investigated the influence of semiconductor film thickness on charge mobilities at the air/P3HT interface. When the film thickness is less than 50 nm, the charge mobilities decrease as the surface energy of PDMS stamps are increased. This implies that air-mediated self-organization is affected by the surface energy of the substrate in the P3HT films that thickness is less than 50 nm, suggesting that the driving force of air-mediated self-organization is weaker than that of substrate-mediated self-organization. The use of air-mediated self-organization is advantageous for fabricating high-performance printed OFETs on conventional organic gate dielectrics and for understanding the interfacial effect of solution-processed OFETs. Air-mediated self-organization can help distinguish between the self-organization effect and the dielectric surface effect. In the case of P3HT films, charge (hole) mobility is strongly influenced by molecular ordering and weakly influenced by hydroxyl groups present at the dielectric surface. On the other hand, in the case of poly[(9,9′-dioctylfluorenyl-2,7-diyl)-(2,2′-bithiophene-5,5′-diyl)] (F8T2) film, hole mobility is influenced by both the molecular ordering and the hydroxyl groups at the dielectric surfaces.
9:00 PM - OO10.13
Efficient Polymer Phosphorescent Light-emitting Diodes Based on Silver Nanowire Electrodes.
Lu Li 1 2 , Zhibin Yu 1 , Qingwu Zhang 1 , Qibing Pei 1 Show Abstract
1 Materials Science and Engineering, University of California, Los Angeles, Los Angeles, California, United States, 2 State Key Laboratory of Electronic Thin Films and Integrated Devices, Department of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu, Sichuan, China
Polymer light-emitting diodes (PLED) are promising candidates for flat panel displays and solid state lighting. Both applications require large-area, low cost transparent electrodes to replace indium-tin oxide. We will present recent progress in achieving efficient blue and white PLED employing silver nanowire electrodes. High device performance has been obtained using a host polymer with a high triplet energy level, blue, green, and red phosphorescent dopants. The balance of opposite charge carrier injections and transport are obtained in the PLED devices having a simple device architecture of Al/CsF/Polymer host and dopants/PEDOT/silver nanowire electrode/polymer substrate. The device performance is comparable to control devices on ITO/glass substrate. The PLED devices are high flexible.
9:00 PM - OO10.14
Saturated Deep-blue Solid-state Light-emitting Electrochemical Cells.
Chih-Teng Liao 1 , Hsiao-Fan Chen 2 , Te-Chuan Chen 1 , Hai-Ching Su 1 , Ken-Tsung Wong 2 Show Abstract
1 Institute of Lighting and Energy Photonics, National Chiao Tung University, Tainan Taiwan, 2 Department of Chemistry, National Taiwan University, Taipei Taiwan
Light-emitting electrochemical cells (LEC’s) in general have several advantages over conventional organic light-emitting diodes (OLEDs), such as the simple single-layer configuration, solution-processing and low operation voltages with air-stable electrodes. However, saturated deep-blue emission, which is essential for full-color display, can not be easily obtained from commonly used LEC materials, e.g. cationic transition metal complexes (CTMCs) and conducting polymers. Reported high-gap Ir-based CTMCs used in LECs have mainly exhibited electroluminescence (EL) in the blue-green region. The difficulty in color-tuning toward the deep-blue region through molecular design of Ir-based CTMCs is mainly due to the intrinsically narrower energy gaps in such cationic complexes relative to those of neutral ones. On the other hand, the EL of LECs based on polyfluorenes (PFs) usually contains significant green emission due to the interchain aggregation, deteriorating color saturation of blue emission coming from PFs. In this work, we report the utilization of an ionic small-molecule fluorene derivative (Fan13) to achieve saturated deep-blue EL from LEC devices. Photoluminescence measurements show highly retained photoluminescence quantum yields of Fan13 in neat films (0.76) as compared to those in solutions (1.00), indicating insignificant self-quenching in condensed phase and thus suitable use as an emissive material of single-layer LECs. Device 1 (neat film) and Device 2 (with 10 wt.% 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM+(PF6)-) to accelerates device response) provided saturated deep-blue EL centered at 424 nm with Commission Internationale de l’Eclairage (CIE) coordinates (x, y) of (0.151, 0.122) and (0.159, 0.115), respectively, extremely close to the blue standard (0.14, 0.08) of the National Television System Committee (NTSC) color gamut. Atomic force microscopy shows no significant difference in film morphologies of Fan13 with and without BMIM+(PF6)-, thus indicating good mixing compatibility of Fan13 and ionic liquids. Device 1 at 3.4 V showed a peak external quantum efficiency (EQE) and a peak power efficiency of 1.04 % and 0.63 lm/W, respectively. Addition of BMIM+(PF6)- (Device 2) improved the carrier balance and decreased the operating voltage and, therefore, increased the EQE and the power efficiency relative to those of the parent neat-film device (Device 1). Device 2 under 3.2 V exhibited a peak EQE and a peak power efficiency of 1.14 % and 1.24 lm/W, respectively. These results successfully demonstrate the bluest EL emissions ever obtained from LECs and suggest that ionic small-molecule fluorene derivatives are promising candidates for saturated deep-blue solid state LECs.
9:00 PM - OO10.16
Comprehensive Investigation of Transient Electroluminescence (EL) Spikes in Small Molecular Organic Light-emitting Diodes (SMOLEDs).
Rui Liu 1 2 , Zhengqing Gan 1 2 , Ruth Shinar 3 4 , Joseph Shinar 1 2 Show Abstract
1 Ames Laboratory - USDOE, Iowa State University, Ames, Iowa, United States, 2 Physics & Astronomy, Iowa State University, Ames, Iowa, United States, 3 Microelectronics Research Center, Iowa State University, Ames, Iowa, United States, 4 Electrical and Computer Engineering, Iowa State University, Ames, Iowa, United States
A comprehensive study of transient EL spikes and tails following a bias pulse in guest-host SMOLEDs, which elucidates carrier and exciton dynamics, is presented. This study is important due to the pulsed-mode operation of SMOLEDs in active matrix displays. The transient EL is dependent on device materials and structure. At low temperatures, all measured devices, with the exception of Pt octaethylporphyrin (PtOEP)-doped tris(8-hydroxyquinoline) Al (Alq3), exhibit the spikes at ~70-300 ns. At room temperature, however, only those with a hole injection barrier, carrier-trapping emitting layer, and no strong electron-transporting and hole-blocking layer exhibit spikes. These narrow and appear earlier under post-pulse reverse bias. To elucidate the spikes’ origin, we monitored their dependence on the bias width and voltage, the doped layer thickness, and its location in the OLED. The characteristics of the microsecond-long tails were also evaluated via the effect of the post-pulse voltage. A model based on the recombination of correlated charge pairs (CCPs) and charge detrapping, which agrees with experiment, is presented. The results suggest that reduced electric field-induced dissociative quenching of CCPs and singlet excitons is responsible for the spikes’ amplitude exceeding the on-pulse EL. The tails are attributed to recombination of charges detrapped from a distribution of shallow sites, reminiscent of the thermally stimulated luminescence of such materials. In addition to systems with charge trapping on the guest, the PtOEP:Alq3 system, where energy transfer dominates, and the triplet exciton emission extends to ~0.1 ms, was also studied, revealing no spike even at low temperature. Hence, the transient EL can distinguish between efficient energy transfer and charge trapping in guest-host OLEDs.*Ames Laboratory is operated by Iowa State University for the US Department of Energy (USDOE) under Contract No. DE-AC 02-07CH11358. This work was supported by the Director for Energy Research, Office of Basic Energy Sciences, USDOE.
9:00 PM - OO10.18
Contact Resistance of P3HT: PCBM Heterojunction Solar Cells.
Yang Shen 1 , Kejia Li 1 , Nabanita Majumdar 1 , Joe Campbell 1 , Mool Gupta 1 Show Abstract
1 Department of Electrical and Computer Engineering, University of Virginia, Charlottesville, Virginia, United States
In this paper, the series resistance of poly (3-hexylthiophene-2,5-diyl) (P3HT) and [6,6]-phenyl C61-butyric acid methyl ester (PCBM) bulk heterojunction (BHJ) organic solar cells has been studied. The series resistance of thermal annealed and un-annealed devices with different active layer thickness was measured. The series resistance of the organic solar cells consists of the bulk resistance of the active layer itself and the specific contact resistance between the active layer and the electrode. The bulk resistance and contact resistance were extracted from the measured series resistance using the vertical transmission line model (TLM) method. By fabricating solar cell devices with different active layer thickness, a relationship of the series resistance with thickness was established from which bulk and the contact resistance was derived. We have also found that the thermal annealing helps reduce both contact resistance and bulk resistance significantly, the contact resistance dropped by a factor of 2, while the bulk resistance decreased by a factor of 10. Results have shown that for an annealed P3HT:PCBM devices which have an active layer thickness of 85 nm (optimum thickness for high efficiency), 17% of the total series resistance was due to contact resistance and bulk resistance contributed the rest 83%. The bulk resistance value for thermal annealed organic solar cell device with an active area of 0.1 cm2 was found to be 150 Ω, and the measured specific contact resistance was 3.1 Ωcm2. The measured bulk and contact resistance values are much higher than compared to the high efficiency silicon solar cells. Bulk resistance and contact resistance need to be further decreased in order to achieve higher organic solar cell efficiency.
9:00 PM - OO10.19
Syntheses of Conjugated Polymers for Solar Cells Using New Electron Deficient Moiety.
Hongsuk Suh 1 , Suhee Song 1 , Joo Young Shim 1 , Youngeup Jin 2 , Sung Heum Park 3 , Kwanghee Lee 3 Show Abstract
1 Department of Chemistry, Pusan National University, Busan Korea (the Republic of), 2 Department of Industrial Chemistry, Pukyong National University, Busan Korea (the Republic of), 3 Department of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju Korea (the Republic of)
Utilization of 2,2-dialkyl-2H-benzimidazole has received strong attention as the electron deficient unit for the generation of electron donor material for organic photovoltaic cells (OPVs). This novel dialkyl-2H-benzimidazole unit has two alkyl groups which can supply higher solubility as compared to that of the BT series. The thin film of new polymer, with dimethyl-2H¬-benzimidazole unit, shows two broad absorption bands with maxima at 400 and 636 nm. The device with PCDTMBI:PC71BM blend demonstrated the efficiency of 3.12%. New other polymers, utilizing dihexyl-2H-benzimidazole, were synthesized using Stille coupling reaction. Even with two bithiophene units in the copolymers to facilitate absorption at the longer wavelength, the incorporation of dihexyl-substituent on 2H-benzimidazole enables the polymers to have good solubility. The device with PEHOPBBTHBI:PC71BM blend demonstrated an open-circuit voltage (VOC) of 0.59 V, a short-circuit current (JSC) of 6.43 mA/cm2, and a fill factor (FF) of 0.39, leading to the efficiency of 1.46%.
9:00 PM - OO10.21
Importance of Molecular Alignment for Opto-electronic Devices.
Roy Vellaisamy 1 , Zong-Xiang Xu 1 Show Abstract
1 Physics and Materials Science, City University of Hong kong, Hong Kong Hong Kong
The search for new classes of organic and metal-organic compounds for molecular electronics is of immense current interest due to the relative low-cost and potential applications in electronic logic circuits. The development of molecular materials represents a new frontier in preparation of high performance opto-electronic devices. In addition, the structural tailorability and multifunctionality of molecules attract huge attention and it is feasible to develop such self-assembly molecules for the incorporation in opto-electronic devices. In this work, we focus on various self-assembled organic/organo-metallic molecular materials and their molecular alignment for the construction of electronic and opto-electronic devices.
9:00 PM - OO10.22
Self-assembly of a Fullerene Poly(3-hexylthiophene) Dyad.
Mingfeng Wang 1 2 3 , Fred Wudl 1 2 3 Show Abstract
1 Department of Chemistry and Biochemistry, University of California, Santa Barbara, California, United States, 2 Center for Polymers and Organic Solids, University of California, Santa Barbara, California, United States, 3 Materials Research Laboratory, University of California, Santa Barbara, California, United States
We report the self-assembly of a C60-capped P3HT dyad molecule (PCB-P3HT) that serves as a “surfactant” to enhance the solubility of fullerenes in poor solvents such as THF, a selective good solvent for P3HT. The phase separation of PCB-P3HT in thin films leads to well-defined nanostructures. Here the solvent plays a vital role in determining the morphology and the structure of these self-assembling structures. PCB-P3HT from THF solution tends to form spherical aggregates in which the methanofullerene (PCB) moieties form a micelle core stabilized by P3HT chains that extend to the solvent medium. In contrast, PCB-P3HT from o-DCB solution forms fibrous structures with a uniform diameter of 15-20 nm and varying lengths up to micrometers. We rationalize that in these fibrous structures the P3HT chains crystallize to form the core, surrounded by a monolayer of C60 moieties. We expect that these different self-assembled structures of PCB-P3HT dyads could be interesting nanoscale model systems for study of photoinduced charge transfer. For example, in the spherical self-assemblies formed from THF solution, photoinduced electrons after the exciton dissociation at PCB/P3HT interfaces would be localized in the micellar core, while photoinduced holes would be localized in the corona. Nevertheless, in the elongated one-dimensional fibrous self-assemblies, we could imagine both holes and electrons tend to be delocalized in the P3HT phase and in the methanofullerene sheath, respectively.
9:00 PM - OO10.23
Simplified Phosphorescent Organic Light Emitting Diode with High Efficiency and Small Efficiency Roll-off.
Zhibin Wang 1 , Michael Helander 1 , Jacky Qiu 1 , Danny Puzzo 1 , Mark Greiner 1 , Zhiwei Liu 1 , Zhenghong Lu 1 Show Abstract
1 Materials Science and Engineering, University of Toronto, Toronto, Ontario, Canada
Organic light emitting diodes (OLEDs) are considered the next generation of technology for flexible flat panel displays and low cost solid state lighting. In particular, phosphorescent organic light emitting diodes (PHOLEDs) that have the potential to achieve an internal quantum efficiency close to 100% have attracted considerable research interest. Much research effort has been devoted to synthesizing new materials and to developing new device architectures to achieve high efficiency. Although high efficiency has been realized at low luminance (e.g., < 100 cd/m2), it is still a significant challenge to obtain a similarly high efficiency at high luminance (e.g., > 5000 cd/m2). The long triplet lifetimes and diffusion lengths result in the notorious efficiency roll-off problem common to all phosphorescent devices at high luminance. In addition to achieving high efficiency, a minimization of efficiency roll-off is also critical for applications that require high brightness, such as solid state lighting. Many different structures have been proposed in literature, such as double emission layers and the incorporation of different blocking layers, to improve the PHOLEDs performance. However, from the practical point of view, a complex device structure with a multuplet of layers will increase the complexity and cost of manufacturing. As will be shown here, all these additional layers are not necessarily needed to achieve high performance PHOLEDs. In this work, a green phosphorescent organic light emitting device that concurrently satisfies: i) a simple structure, ii) a high efficiency and iii) a low efficiency roll-off has been demonstrated. In particular, the external quantum efficiency (EQE) drops < 1 % from 100 cd/m2 to 5000 cd/m2 and reaches ~20% at 10,000 cd/m2. The EQE can be further boosted up to > 50 % at 10000 cd/m2 by employing our optical out-coupling technique, i.e. an innovative development of optical out-coupling without using the high-index glass substrate.
9:00 PM - OO10.24
Toward Predictive Modeling of 3D Bulk Heterojunction in Organic Solar Cells.
Olga Wodo 2 , Baskar Ganapathysubramanian 2 1 Show Abstract
2 Mechanical Engineering Department, Iowa State University, Ames, Iowa, United States, 1 Electrical and Computer Engineering, Iowa State University, Ames, Iowa, United States
The past decade has witnessed considerable advances in organic photovoltaic technology both from the perspective of understanding the physical aspects of the underlying processes, as well as concurrent improvement in efficiencies. This improvement was made possible through a three pronged approach: (a) new materials development (e.g. PTB systems); (b) new device designs (e.g. tandem cells); and (c) morphology control during manufacturing process. Despite these significant improvements in both fundamental understanding as well as device enhancements, there still remain several potential issues that thwart wide-spread use and profitable commercial production of OSC. One major challenge is the weak control over manufacturing process to get tailored morphologies. Current state-of-the-art approaches to understanding morphology evolution and tailoring manufacturing process for high efficiency OSCs are either limited to combinatorial trial-and-error based experimental investigation or single scale analysis. Experimental techniques, however, provide limited data for analysis (limited to final morphology and mostly to lateral cross sections). The main reasons for that are mostly related to the difficulty of attaining high spatial resolution and the requirement of good contrast between components. These challenges hinder our ability to understand and subsequently control the interaction of multiple factors affecting morphology evolution. These challenges serve as a rational for developing a computational framework that can be used to analyze morphology evolution thus significantly augmenting experimental analysis and opening up new possibility of data-driven knowledge discovery.In our approach we use a phase field approach to develop a predictive theory for the evolution of morphology during solvent-based fabrication of organic solar cells. We model evaporation-induced phase-separation in ternary systems, which consist of conjugated polymer, fullerene derivative and solvent. The model takes into account both thermodynamic (e.g. interaction parameters between components) and kinetic parameters (e.g. diffusion coefficient). To enable quantitative prediction we equip the model in material-specific parameters obtained via molecular dynamic simulation. Additionally to augment the device scale simulation we develop an efficient, multiscale computational framework to model evolution of three dimensional bulk heterojunction structures. We showcase the framework by investigating the effect of fabrication parameters (e.g. evaporation rate) and system parameters (e.g. type of solvent, blend ratio) on the morphology during two currently competitive solvent based fabrication techniques: spin coating and drop casting.
9:00 PM - OO10.25
Tacticity Directed Solution Self-assembly in Small Molecule Organic Semiconductor – Polymer Blends.
Stephen Yeates 1 , Marie-Beatrice Madec 1 Show Abstract
1 Chemistry, University of Manchester, Manchester United Kingdom
The role of polystyrene as a structural scaffold in the nucleation and self assembly of solution processable small molecule organic semiconductors is demonstrated. The nature of the tacticity of polystyrene is found to influence the nature of the solution aggregation behaviour of 6,13 triisopropylsilyletynylpentacene (TIPS-pentacene) with small molecule and polymer matrix interaction being dominated by van der Waals dispersion forces between the π orbitals favouring a parallel (S shape) or perpendicular (T shape) contact. Fluorescence spectroscopy reveals that TIPS-pentacene forms supramolecular clusters well below the solubility limit, with a small monomer signal being observed at very high dilution decaying rapidly with increased concentration. Clusters in the form of dimer or higher organised structure are influenced by addition of a polymer matrix which enhances the emission and shifts the maximum free dimer and monomer concentration in solution depending upon tacticity. Neutron scattering analysis exhibits a dramatic difference between the TIPS-pentacene and the polystyrene interaction dependent upon its tacticity.Isotactic polystyrene demonstrates synergistic pi-pi stacking interactions with TIPS-pentacene, resulting in longer range crystalline order of the semiconductor when deposited from solution when compared with the semiconductor on its own. This is manifested as higher organic thin film transistor performance and improved discrete device to device performance [1,2].1. Thermo-mechanical stabilisation of a crystalline organic semiconductor for robust large area electronics. Organic Electronics. M. M. Ibrahim, A. C. Maciel, C. P. Watson, M.-B. Madec, S. G. Yeates and D.M. Taylor, Organic electronics (2010), 11, 1234-1241.2. Organic field effect transistors from ambient solution processed low molar mass semiconductor-insulator blends. Madec, Marie-Beatrice; Crouch, David; Llorente, Gonzalo Rincon; Whittle, Tracie J.; Geoghegan, Mark; Yeates, Stephen George. Journal of Materials Chemistry (2008), 18(27), 3230-3236.
9:00 PM - OO10.28
Narrow-bandgap Copolymer Based on Diketo-Pyrrolo-Pyrrole /Cyclopentadithiophene for Polymer Solar Cells.
Kanpitcha Jiramitmongkon 1 , Phimwipha Piyakulawat 1 , Anusit Keawprajak 1 , Michael Forster 2 , Udom Asawapirom 1 Show Abstract
1 , National Nanotechnology Center, Pathumthani Thailand, 2 Macromolecular Chemistry, University of Wuppertal, Wuppertal Germany
The electroactive conjugated polymers have been extensively used for photovoltaic cells [1-2]. The key attributes of the polymer contributing to high power conversion efficiency (PCE) have been identified to include high hole mobility and good miscibility with the acceptor material to maximize the bulk-heterojuntion area [3-5]. Moreover, the important parameter for optimization of polymer photovoltaic cells is the bandgap of the donor materials. For single junction cells, using  PCBM as acceptor, a bandgap lower than 2.0 eV is expected to be optimal, provided that the HOMO and LUMO levels are correctly positioned with respect to the levels of the electron acceptor. In this study, we have synthesized a new low band gap copolymer based on diketo-pyrrolo-pyrrole and cyclopentadithiophene for using as donor material. The polymer was polymerized through a Stille cross-coupling reaction via Palladium complex catalyzed and confirmed the chemical structure by NMR. The obtained copolymer absorbs light in wide range from 300 to 750 nm. The energy band gap was estimated by UV-vis and electrochemical studies. Photovoltaic cells were fabricated via spin-coating method by using the blend of the obtained copolymer and PCBM in various ratios as an active layer. The best device performance was achieved at the copolymer/PCBM weight ration of 1:3 under the illumination of A.M. 1.5, 100mw/cm2.
9:00 PM - OO10.3
Bimolecular Recombination and Energetic Disorder in Low-gap Polymer Solar Cells.
Song Chen 1 , Jegadesan Subbiah 1 , Chad Amb 2 , John Reynolds 2 , Franky So 1 Show Abstract
1 Dept of Materials Science and Engineering, University of Florida, Gainesville, Florida, United States, 2 The George and Josephine Butler Polymer Research Laboratory, Department of Chemistry, Center for Macromolecular Science and Engineering, University of Florida, Gainesville, Florida, United States
Low-gap polymer poly ((4, 4- dioctyldithieno (3,2-b:2',3'-d) silole) -2,6- diyl-alt- (2,1,3- benzothiadiazole) -4,7-diyl) (DTS-BTD) is a promising material for donor-acceptor bulk heterojunction solar cell applications with a wide-absorption band and excellent transport. While the solar cell short-circuit current exceed 15 mA/cm2, its power conversion efficiency is limited by its fill factor as well as external quantum efficiency. In order to study the loss mechanism of photo-current, we carried out transient photo-voltage (TPV) experiments to probe the bimolecular recombination of photo-carriers under open circuit condition. Together with photo-CELIV (carrier extraction by linearly increasing voltage) data, we will present a device model explaining the loss mechanism in this type of donor-acceptor photovoltaic system.Solar cells were fabricated with the following structure: ITO/ ZnO/ DTS-BTD:PCBM/ MoO3/ Ag. TPV measurements were carried out directly on the solar cell by using two light sources. A solar simulator provides a constant light bias to the device while the sample is modulated by a pulsed laser with durations of 5 ns. The photo-carriers lifetime was extracted by probing the decay of the photo-generated carriers. Our results show the polymer: fullerene system (DTS-BTD: PCBM) has a photo-carrier lifetime of 400 ns at open circuit condition, which corresponds to a k/kL ratio (kL is the Langevin mode recombination coefficient) over 10-1. In contrast, conjugated polymer: fullerene system (poly-3(hexylthiophene) (P3HT): PCBM) has a lifetime of 8 μs with a k/kL ratio < 10-2. The difference in lifetime between the two systems is consistent with the device performance data. Thus, the recombination at open circuit condition is a strong limiting factor for DTS-BTD: PCBM. Finally, we will correlate the photo-carrier lifetime with the degree of energetic disorder (diagonal disorder) of the polymer materials. Based on the Marcus theory small polaron model, the bound electron-hole pair lifetime is limited due to a large population of tail states in the HOMO band. Our mobility data that the DTS-BTD: fullerene system shows much higher energetic disorder than P3HT: PCBM are consistent with the small polaron model.
9:00 PM - OO10.30
A Facile Transferring Method to Fabricate a Light Harvesting System for Polymer Solar Cells.
Yu-Sheng Hsiao 1 , ChiungWen Kuo 1 , Chih-Wei Chu 1 , Peilin Chen 1 Show Abstract
1 Research Center for Applied Sciences, Academia Sinica, Taipei Taiwan
A simple light harvesting system with two-dimensional (2D) periodic granular-like electrodes was fabricated using transferring process for polymer solar cells (PSCs). This transferring technique, which was based on nanosphere lithography, could be used to fabricate periodic nanostructures on both photoactive layers and Al electrodes in the normal PSC device configuration (ITO glass/PEDOT:PSS/photoactive layer/Al). The properties of the PSC devices with periodic nanostructures in the photoactive layers have been investigated by several techniques, including reflection UV-vis spectra, external quantum efficiency (EQE), photocurrent–voltage characteristics. In addition, the electromagnetic field distribution for devices as evaluated by numerical simulation. It has been demonstrated that the light trapping efficiency in the PSCs with periodic nanostructures has been enhanced due to light scattering and localized surface plasmon resonance (LSPR). When compared to conventional devices with flat geometry, the power conversion efficiency (PCE) of the small thickness of photoactive layer (ca. 150 nm) of P3HT/C70 bi-layer devices with periodic nanostructures has been increased by 90%. Furthermore, when the bulk heterojunction (BHJ) devices with low absorption coefficient photoactive layer (PTPTBT:PC70BM) were engineered with periodic nanostructures, 20% enhancement in photocurrent has been observed, which suggested that this facile light harvesting system be suitable for both small thickness or low bandgap polymer solar cell applications.
9:00 PM - OO10.31
Effects of Substituted Side Chains on the Optical and Electrical Properties of D-A Conjugated Copolymers.
Shinuk Cho 1 , Sangkyu Lee 2 , Minghong Tong 3 , Jung Hwa Seo 3 , Hongsuk Suh 4 , Alan Heeger 3 Show Abstract
1 Department of Physics, University of Ulsan, Ulsan Korea (the Republic of), 2 Energy Materials Research Center, Korea Research Institute of Chemical Technology (KRICT), Daejeon Korea (the Republic of), 3 Center for Polymers and Organic Solids, University of California at Santa Barbara, Santa Barbara, California, United States, 4 Department of Chemistry, Pusan National University, Busan Korea (the Republic of)
Because of the low band-gap property together with relatively high hole mobilities, conjugated copolymers containing electron donor–acceptor (D-A) repeating units have drawn considerable attention for use as active materials in organic electronic devices, such as bulk heterojunction (BHJ) photovoltaic (PV) cells and polymer field-effect transistors (FETs). Although the conjugated core units of D-A conjugated copolymers convey solubility, D-A copolymers have relatively low solubility if they have a high molecular weight (Mw). As a simple way to improve the solubility of high molecular weight D-A copolymers, alkyl or alkoxy side chains may be introduced at the thiophene unit. Substitution of side chains in conventional conjugated polymers, however, often alters the configuration of the conjugated chain, thereby affecting the electronic properties. In this presentation, the effects of several substituted side chains (alkyl or alkoxy) on the optical and electrical properties of D-A conjugated copolymers will be presented. The substituted alkyl or alkoxy side chains significantly altered the optical and electrical properties of D-A conjugated copolymers due to steric hindrance. In addition, the effects of the position of substituted side chains (alkyl) on the optical and electrical properties of D-A conjugated copolymers also will be dicsessued. The intrinsic properties of the copolymers were significantly altered by perturbations of the intramolecular charge transfer (ICT) between the donor and acceptor segments.
9:00 PM - OO10.32
Synthesis of Novel Double Spiro Core Structure and Efficiency Improvement of Green Phosphorescent Organic Light Emitting Diodes Using Double Spiro Based Hole Transport Materials.
Yong Joo Cho 1 , Chang Woo Seo 1 , Oh Young Kim 1 , Jun Yeob Lee 1 Show Abstract
1 Polymer Science and Engineering, Dankook University, Yongin-si, Gyeonggi-do Korea (the Republic of)
A novel double spiro structure was designed and synthesized as the core structure of hole transport materials for green phosphorescent organic light-emitting diodes. The double spiro core structure was prepared by one step or two step ring closing methods to functionalize the double spiro core at different positions. Two hole transport materials, double spiro compound with two diphenylamines at different fluorene moiety (DSPN1) and double spiro compound with two diphenylamines at the same fluorene moiety (DSPN2), were effectively synthesized by the two step and one step ring closing methods, respectively. The triplet energies of the DSPN1 and DSPN2 were calculated to be 2.53 eV and 2.40 eV, respectively. The quantum efficiency of green phosphorescent organic light-emitting diodes was improved by more than three times using the DSPN1 and DSPN2 instead of common N,N′-di(1-naphthyl)-N,N′-diphenylbenzidine hole transport material. Maximum quantum efficiency of the DSPN1 device was 19.2 %. The double spiro structure was effective as the core structure of hole transport material and can be used as the core of host or electron transport materials due to thermal stability and high triplet energy.
9:00 PM - OO10.33
Effect of Tert Butyl Group in Asymmetric Stilbene Based Compounds on the Performance of Blue Organic Light Emitting Diodes.
Kyoung Soon Choi 1 , Hyunjong Jo 1 , Kwangyong Park 1 , Soo Young Kim 1 , Bon Hyeong Koo 2 , Kihyon Hong 2 , Jong-Lam Lee 2 Show Abstract
1 School of Chemical Engineering and Materials Science, Chung-Ang University, Seoul Korea (the Republic of), 2 Department of Materials Science and Engineering, Pohang University of Science and Technology, Pohang Korea (the Republic of)
The effect of derivatives in asymmetric stilbene based compounds on the performance of blue organic light emitting diodes (OLEDs) was investigated. Organic compounds were synthesized with respect to number and location of methyl and tert butyl groups. Red shift in photoluminescence (PL) spectra and decrease of difference in PL main peak between solid state and solution state were observed as the number of tert butyl in organic compounds is decreased, indicating that tert butyl group prohibit the formation of planar structure, reducing chromophoric phi-phi interaction followed by reducing fluorescence quenching. Luminance value of OLEDs used in tert butyl-tert butyl functional group as an active layer was the highest value due to reduction of fluorescence quenching. Therefore, it is considered that tert butyl group is very efficient in stilbene based compound to prohibit fluorescence quenching. [Acknowledgements]This research was supported in part by Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Education, Science and Technology(2010-0011590) and in part by Seoul R&BD program (ST10004M093171).
9:00 PM - OO10.34
High Molecular Weight Donor-acceptor Copolymers based on Benzo[1,2-b:4,5-b']dithiophene.
Robert Coffin 1 , Christopher MacNeill 2 , Eric Peterson 1 , Wanyi Nie 1 , Gregory Smith 1 , Ronald Noftle 2 , David Carroll 1 Show Abstract
1 Physics, Wake Forest University, Winston-Salem, North Carolina, United States, 2 Chemistry, Wake Forest Univeristy, Winston-Salem, North Carolina, United States
There have been many reports of high efficiency organic solar cells comprised of BDT copolymers, which prompted us to investigate these materials. We were particularly interested in a copolymer of BDT with benzothiadiazole (BT). This repeat unit structure, bearing bearing dodecyloxy chains at the 4 and 8-positions of the BDT monomer, had been previously reported, and shown to have attractive HOMO and LUMO levels for organic solar cell applications. Upon synthesizing this copolymer in our lab, we found the majority of the isolated material was insoluble, while the chloroform soluble fraction had an Mn less than 5 kDa. Not unexpectedly this resulted in poor device performance. To improve molecular weight we altered the side chain to undecan-6-yloxy (1-pentylhexyl), a large branched chain which had not been previously used in BDT copolymers. This resulted in a freely soluble, high molecular weight (> 30 kDa), BDT-BT copolymer. With this new BDT monomer in hand we investigated copolymers of BDT with several other acceptor monomers including benzoxadiazole (BO) and benzoselenadiazole (BS). The chloroform soluble fractions of all our copolymers show similarly high Mn’s allowing for valid comparisons between elements of the repeat unit structure, and the physical properties and device performance of the materials. We find that not only can large changes in LUMO levels and bandgap be achieved through varying the acceptor comonomer, but contrary to conventional wisdom we also see large changes in HOMO levels. Despite the bulky side chains increasing pi-pi stacking distances to greater than 3.8 Å as determined by powder XRD (compared with ~3.6 Å, for the dodecyloxy analogs), higher power conversion efficiencies can be obtained from the 4,8-bis(undecan-6-yloxy)BDT copolymers, indicating the benefits of high molecular weight outweigh those of close inter-chain spacing.
9:00 PM - OO10.36
High-performance Multilayered Blue Phosphorescent Organic Light-emitting Diodes Achieved by Sequential Solution-processing Method.
Taeshik Earmme 1 , Eilaf Ahmed 2 , Samson Jenekhe 1 2 Show Abstract
1 Chemical Engineering, University of Washington, Seattle, Washington, United States, 2 Chemistry, University of Washington, Seattle, Washington, United States
We report high-performance multilayered polymer-based blue phosphorescent organic light-emitting diodes (PhOLEDs) achieved by a new electron-transport material, TQB (1,3,5-tris(4-phenylquinolin-2-yl)benzene) with sequential solution-processing method. Current high-performance blue PhOLEDs have mainly focused on using vacuum deposited small organic molecules, involving thermal evaporation processes to obtain multilayered device structures, which severely affect the device fabrication cost. Solution processed PhOLEDs provide an attractive alternative to those processed by vacuum deposition. Using a solution-processable electron-transport layer (ETL), we observe a large improvement of the device performance compared to vacuum deposited ETL. By virtue of the high electron affinity (3.42 eV) and a deep HOMO energy level (-6.82 eV), TQB serves as an efficient electron-transport layer (ETL) and a good hole-blocking layer (HBL). The unique TQB ETL surface formed by solution-processing enables the high quality TQB/Al interface formation, resulting in efficient electron-injection/transport into the devices. We expect the solution-processing approach demonstrated here for high performance blue PhOLEDs to be also applicable to different colors of OLEDs / PhOLEDs as well as other solution-processed multilayered organic electronic devices.
9:00 PM - OO10.37
Materials for Hole-injection/Transport Layers of Organic Light-emitting Diodes Fabricated by Solution Processing.
Shigeaki Funyu 1 , Kenichi Ishitsuka 1 , Yosuke Hoshi 1 Show Abstract
1 , Hitachi Chemical, Tsukuba-shi Ibaraki Japan
Organic light-emitting diodes (OLEDs) have attracted considerable attention because of their potential application to solid-state lighting and display.Efficient OLED devices composed of multilayer structures are generally manufactured by using vacuum vapor deposition or solution processing. As compared to vacuum vapor deposition under strict manufacturing conditions, a multilayer coating technique using solution processing affords a lower cost of production and is easy to magnify the area of layers. However, a serious drawback of this method is the erosion of the bottom layer by a solvent used in a subsequent step. One of the development targets in the field of OLEDs, therefore, is to utilize orthogonal solvents or cross-linkable materials to overcome this problem; many research groups are working to achieve this. Here, we report a series of hole-injection/transporting polymers having cross-linkable substituents for solution proces