Available on-demand - *S.CT05.04.19
Defect-Engineered Multinary Chalcogenide Solar Absorber Materials
Zinc-blende-related chalcogenide semiconductors CdTe and Cu(In,Ga)(S,Se)2 (CIGS) currently represent the fastest growing commercial thin-film photovoltaic (PV) technologies. To address prospective scalability issues related to elemental scarcity (Te, In) and/or heavy-metal toxicity (Cd), Cu2ZnSn(S,Se)4 (CZTS) has also been vigorously pursued as a prospective drop-in replacement for CIGS, but efficiency improvement has been hindered by adverse defect characteristics (band tailing and deep defects), in part due to the similarity in chemistry among component metals and associated anti-site disordering. This talk will discuss promising emerging alternative multinary chalcogenides based on earth-abundant Cu2BaSn(S,Se)4 (CBTS) as an example, which offer similarities to CZTS in terms of electronic structure, but with introduced atomic size and coordination preference differences that reduce likelihood of atomic disordering—i.e., the much larger Ba ion, occupying a site that has 8-fold coordination rather than 4-fold (as for Cu, Zn and Sn in CZTS), reduces the probability of anti-site disordering and associated defects [1,2]. Simple solution- and vacuum-based film deposition processes enable fabrication of absorber layers with initial PV device sunlight-to-electricity power conversion efficiencies exceeding 5% for CBTS [3,4] and analogous photoelectrochemical (PEC) cells yielding a stable (over 10 hr) 12 mA/cm2 photocurrent at 0 V/RHE . This talk will discuss aspects of defect engineering within this family, as well thoughts on design strategies for expanding the known members of the I2–II–IV–VI4 family beyond CBTS (e.g., ). If desirable electronic structure tunability associated with a multi-element stoichiometry can be combined with earth-abundant components and control over defect formation, multinary chalcogenides may provide a bright path forward in the quest for high-performance, low-cost and scalable PV and PEC devices.
 D. Shin, B. Saparov, T. Zhu, W. P. Huhn, V. Blum, D. B. Mitzi, Chem. Mater. 28, 4771 (2016).
 D. Shin, B. Saparov, D. B. Mitzi, Adv. Energy Mater. 7, 1602366 (2017).
 D. Shin, T. Zhu, X. Huang, O.Gunawan, V. Blum, D. B. Mitzi, Adv. Mater. 29, 1606945 (2017).
 B. Teymur, Y. Zhou, E. Ngaboyamahina, J. T. Glass, D. B. Mitzi, Chem. Mater. 30, 6116 (2018).
 Y. Zhou, D. Shin, E. Ngaboyamahina, Q. Han, C. Parker, D. B. Mitzi, J. T. Glass, ACS Energy Lett. 3, 177 (2018).
 T. Zhu, W. P. Huhn, G. C. Wessler, D. Shin, B. Saparov, D. B. Mitzi, V. Blum, Chem. Mater. 29, 7868 (2017).