Hybrid organic inorganic perovskite solar cells based on CH3NH3PbI3have drastically increased in efficiency over the past several years and are competitive with decades‐old photovoltaic materials such as CdTe. Despite this impressive increase, significant issues still remain due to the intrinsic instability of CH3NH3PbI3which degrades into carcinogenic PbI2. Recently, double halide perovskites which use a pair of 1+–3+cations to replace Pb2+, such as Cs2InSbI6, and chalcogenide perovskites, such as BaZrS3, have been explored as potential replacements. In this work, double chalcogenide perovskites are explored to identify novel photovoltaic absorbers that can replace CH3NH3PbI3. Due to the large space of possible compounds, machine learning methods are used to classify materials as potential photovoltaic absorbers using data from the periodic table, eliminating wasteful computation. A random forest algorithm achieves a cross‐validation accuracy of 86.4% on the constructed data set. Over 450 possible replacements are identified via traditional and statistical methods with Ba2AlNbS6, Ba2GaNbS6, Ca2GaNbS6, Sr2InNbS6, and Ba2SnHfS6as the most promising alternative when thermodynamic stability, kinetic stability, and optical absorption are considered.
Metal halide perovskites (MHPs) have attracted broad research interest due to their outstanding optoelectronic performance. This performance has been attributed in part to the presence of polarization in these materials. However, the precise effects of chemical environment and strain condition on the polar states in MHPs have largely been missing. It is revealed for the first time that chemical gradient is directly coupled with strain gradient in CH3NH3PbI3. This strain–chemical gradient induces an electric polarization that can potentially affect charge carrier dynamics. Furthermore, it is unveiled that this electric polarization—unlike ferroelectricity that only exists in noncentrosymmetric materials—can be present in both tetragonal and cubic phases of CH3NH3PbI3. This suggests that the strain–chemical gradient induced polarization is a more convincing explanation of the outstanding photovoltaic properties of MHPs than the hotly debated ferroelectric polarization. Finally, a mechanism of how this polarization impacts photovoltaic action is proposed, which offers insightful advances in the development of MHPs.more » « less
- NSF-PAR ID:
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Electronic Materials
- Medium: X
- Sponsoring Org:
- National Science Foundation
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