Low-cost air-stable perovskite solar cells by incorporating inorganic materials

Abstract

Herein, we demonstrate a new fabrication strategy for low-cost and stable-operation perovskite solar cells (PSCs) suitable for commercialization. This is performed by fabrication of the device under ambient conditions using a Cs_0.05(MA_0.17FA_0.83)_0.95Pb(Br_0.17I_0.83)₃ formulation as the mixed cation and halide (MCH) perovskite and CuInS₂ (CIS) as the inorganic hole transporting layer. The deposited MCH perovskite with uniform, compact and smooth microstructure containing equiaxed large grains showed excellent thermal and structural stability under intense conditions at 85 °C for 2 h in humid air (i.e., 45% relative humidity). Moreover, it had higher phosphorescence emission, absorption and bandgap energy than the conventional MAPbI₃ due to efficient conversion of PbI₂ to the perovskite compound, as further confirmed by XRD analysis. Photovoltaic measurements under operational conditions revealed that the MCH-based PSC showed a 27% higher photoconversion efficiency compared with the control device composed of MAPbI₃ caused by less charge recombination. The CIS-based MCH device aged for 30 days at 25 °C and 40% humidity retained 91% of the maximum efficiency with a low standard deviation of all photovoltaic parameters, indicating excellent potential for industrialization.