Discovering lead-free perovskite solar materials with a split-anion approach.
Organic-inorganic hybrid perovskite solar materials, being low-cost and high-performance, are promising for large-scale deployment of the photovoltaic technology. A key challenge that remains to be addressed is the toxicity of these materials since the high-efficiency solar cells are made of lead-containing materials, in particular, CH3NH3PbI3. Here, based on first-principles calculation, we search for lead-free perovskite materials based on the split-anion approach, where we replace Pb with non-toxic elements while introducing dual anions (i.e., splitting the anion sites) that preserve the charge neutrality. We show that CH3NH3BiSeI2 and CH3NH3BiSI2 exhibit improved band gaps and optical absorption over CH3NH3PbI3. The split-anion approach could also be applied to pure inorganic perovskites, significantly enlarging the pool of candidate materials in the design of low-cost, high-performance and environmentally-friendly perovskite solar materials.
Department of Physics, Applied Physics & Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180, USA. suny4@rpi.edu zhangs9@rpi.edu.
Yi-Yang
YY
Sun
Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, USA.
Jian
J
Shi
Department of Mechanical, Aerospace, and Nuclear Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, USA.
Jie
J
Lian
Department of Physics, University at Buffalo SUNY, Buffalo, New York 14260, USA.
Weiwei
W
Gao
Department of Physics, Applied Physics & Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180, USA. suny4@rpi.edu zhangs9@rpi.edu.
Michael L
ML
Agiorgousis
Department of Physics, University at Buffalo SUNY, Buffalo, New York 14260, USA and Beijing Computational Science Research Center, Beijing 100084, China.
Peihong
P
Zhang
Department of Physics, Applied Physics & Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180, USA. suny4@rpi.edu zhangs9@rpi.edu.
Shengbai
S
Zhang