MRS Meetings and Events


EL07.05.02 2023 MRS Spring Meeting

Improving the Dispersion of Silicon/Silicon Dioxide Quantum Dots

When and Where

Apr 12, 2023
5:00pm - 7:00pm

Moscone West, Level 1, Exhibit Hall



Adriana Chapa1,2,Kristine Loh1,Vivian Ferry1,Uwe Kortshagen1

University of Minnesota1,The University of Texas Rio Grande Valley2


Adriana Chapa1,2,Kristine Loh1,Vivian Ferry1,Uwe Kortshagen1

University of Minnesota1,The University of Texas Rio Grande Valley2
Through the years there has been a growing need for renewable energy sources. Luminescent Solar Concentrators (LSCs) are semitransparent devices that generate renewable electricity. LSCs are composed of a transparent polymer waveguide with embedded luminescent nanocrystals. Silicon Quantum Dots (Si QDs) are semiconductor nanocrystals that broadly absorb UV light and photoluminesce near-infrared light. Si QDs are suitable for LSC applications as they are nontoxic and made from an abundant element.<br/>This work focuses on developing a method to disperse core/shell Si/SiO2 QDs in a solvent. Various aspects of the dispersion were studied by experimenting with different ligands, pH levels, and solvents. We tested two different ligands, (3-Glycidyloxypropyl) trimethoxy silane (GPTMS) and polyethylene glycol, two different pH level additives, ammonium hydroxide (NH4OH) and hydrochloric acid, and different solvents including ethanol, H2O, and toluene.<br/>The dispersions were characterized using Fourier transform infrared (FTIR), UV-Visible, and photoluminescence (PL) spectroscopies. First, the ligands GPTMS and polyethylene glycol (PEG)-silane were tested. The solution contained 100 µL of HCl, 1.5 mL of ethanol and 0.3 mL of H2O. The dispersion of the Si/SiO2 with GPTMS and HCl settled faster than the Si/SiO2 with PEG-silane and HCl dispersion. Using UV-Vis, the Si/SiO2 with GPTMS absorbance is higher than the absorbance of the Si/SiO2 with PEG-silane due to scattering from the larger agglomerates that settled. The samples in HCl were more stable than ones using ammonium hydroxide. FTIR measurements confirmed that the Si/SiO2 QDs were coated with PEG-Silane.<br/>Lastly the dispersions were characterized using photoluminescence spectroscopy. The Si/SiO2 QDs in toluene and Si/SiO2 QDs in PEG-silane show that the solutions can have similar photoluminescence intensities even though the toluene dispersion sample agglomerates. Si/SiO2 QDs in H2O agglomerate faster relative to the QDs in ethanol. In conclusion, using PEG-silane as a ligand in an acidic environment with a polar solvent led to a stable, homogeneous mixture with a high photoluminescence intensity.


quantum materials | Si

Symposium Organizers

Katerina Kusova, Czech Academy of Sciences
Lorenzo Mangolini, University of California, Riverside
Xiaodong Pi, Zhejiang University
MingLee Tang, University of Utah

Symposium Support

Magnitude Instruments
Royal Society of Chemistry

Publishing Alliance

MRS publishes with Springer Nature