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DOE OSTI · 1808291

Strain-relaxed tetragonal MAPbI 3 results in efficient mesoporous solar cells

Ye, Tao·Wang, Kai·Ma, Shaoyang·Wu, Congcong·Hou, Yuchen·Yang, Dong·Wang, Ke·Priya, Shashank
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Abstract

In mesoporous organo-halide perovskite solar cells, the coexistence of tetragonal phase and cubic phase in the perovskite layer is found to result in strained crystal structure at the mesoporous TiO 2 (mp-TiO 2 )/perovskite heterointerface. This results in structural defects pinholes, grain boundaries, and interfacial porosity which is detrimental towards photovoltaic performance and device stability. The strain at the interface originates from the lattice mismatch between the mp-TiO 2 nanoparticles (NPs) and perovskite. Here, a transformative approach is demonstrated to realize relaxed and high purity tetragonal phase MAPbI 3 (RP) near the mp-TiO 2 interface region. This approach involves inserting a ~2 nm lattice matched buffer layer of cubic CsPbBr 3 between mp-TiO 2 NPs and MAPbI 3 , which serves as a template for epitaxial growth for top MAPbI 3 . As a result, the solar cell with relaxed MAPbI3 shows a power conversion efficiency (PCE) of 22.12% with significantly enhanced environmental, light, and thermal stability.

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14 SOLAR ENERGYInterfaceInterfacial lattice strainLattice matchMesoporous perovskite solar cellPerovskitePhase coexistencePhotovoltaicPure tetragonal phaseSolar cellStrain

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Ye, Tao, Wang, Kai, Ma, Shaoyang, Wu, Congcong, Hou, Yuchen, Yang, Dong, Wang, Ke, Priya, Shashank. 2021-01-18. Strain-relaxed tetragonal MAPbI 3 results in efficient mesoporous solar cells. https://doi.org/10.1016/j.nanoen.2021.105788

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