oa Designing Photo Absorbing Materials by Cation Substitutions for Photovoltaics

Designing Photo Absorbing Materials by Cation Substitutions for Photovoltaics Merid Legesse1, Heesoo Park1, Fedwa El Mellouhi1, Sergey N Rashkeev1, Sabre Kais1, 2, 3, Fahhad H Alharbi1, 3 1Qatar Environment and Energy Research Institute, Hamad Bin Khalifa University, Doha, Qatar. 2Department of Chemistry and Physics, Purdue University, West Lafayette, Indiana 46323, USA. 3College of Science and Engineering, Hamad Bin Khalifa University, Doha, Qatar. Email: [email protected]. Recently, significant research efforts have focused on some emerging solar cell technologies such as dye-sensitized solar cells, perovskite photovoltaics, etc. However, these technologies face many challenges. In this talk, we will present a new family of light absorbing materials so-called pyroxene silicates. These materials are abundantly present in the earth crust however, bandgaps of naturally formed pyroxene silicates such as NaAlSi2O6 are quite high (∼5 eV). Therefore, it is important to find a way to reduce bandgaps below 3 eV to make them usable for optoelectronic applications [1, 2, 3]. Using first-principles calculations we investigated the possibility of band structure engineering of pyroxene silicates with chemical formula A+1B+3Si2O6 by proper cation substitution (A+ =  Na, NH4+, PH4+, SH3+, CH3NH3+, CH3PH3+, CH3SH2+ and B3+ =  Al3+ Ga3+, In3+, Tl3+). We found that appropriate substitutions of both A+ and B3+ cations can reduce the bandgaps of these materials to as low as 1.31 eV. In this talk, we will also discuss in details how the bandgap in this class of materials is affected and thermodynamic stabilities. We would like to thank Qatar National Research Foundation (QNRF) for the support (Grant No. NPRP 7-317-1-055. References (1) A.A.B. Baloch, S.P. Aly, M.I. Hossain, F. El-Mellouhi, N. Tabet, and F.H. Alharbi, Sci. Rep. 7, 11984 (2017). (2) F. El Mellouhi, A. Akande, C. Motta, S.N. Rashkeev, G. Berdiyorov, M.E.A. Madjet, A. Marzouk, E.T. Bentria, S. Sanvito, S. Kais, and F.H. Alharbi, ChemSusChem 10 1931 (2017). (3) F.H. Alharbi, S.N. Rashkeev, F. El-Mellouhi, H. P. Lüthi, N. Tabet, S. Kais, npj Comput. Mater 1, 15003 (2015).