Proceedings of Asia-Pacific International Conference on Perovskite, Organic Photovoltaics and Optoelectronics (IPEROP24)
Publication date: 18th October 2023
Lead-halide perovskite solar cells are among the fastest-growing solar cell technologies. However, concerns about the toxicity of these solar cells have led to extensive exploration of lead-free perovskite materials as potential alternatives. Among these lead-free perovskite materials, tin halide has exhibited similar optoelectronic properties, including excellent absorption coefficient, low exciton binding energy, high charge mobility, and excellent photoluminescent quantum yield when compared to their lead halide counterparts[1].
Various strategies such as substitution/addition engineering, 2D-3D engineering, solvent engineering, and interface passivation have been successfully employed to enhance the photoelectric performance of tin halide perovskite solar cells. These strategies have effectively mitigated the undesired oxidation of tin halide perovskite[1]. Tin halide perovskite also demonstrates high p-mobility. Previous research has shown that treating the tin halide perovskite surface with a Lewis base can convert its surface properties from p-type to n-type, resulting in a significantly improved electron collection and thereby supporting increased photoconversion efficiency[2].
Inspired by these results, we fabricated tin halide perovskite solar cells utilizing the n-type electronic properties of [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). We integrated PCBM into the tin halide perovskite ink, creating a modified perovskite ink for fabricating tin halide perovskite solar cells in an inverted structure. This approach effectively distributed PCBM along the grain boundaries within the bulk of tin halide perovskite. As a result, we achieved an enhanced photoconversion efficiency of 12.68 % (short circuit current density (Jsc)=23.85 mA/cm2, open circuit voltage (Voc)= 0.73V, fill factor (FF)=0.72) compared to the 10.25% of reference cells (Jsc= 22.51 mA/cm2, Voc=0.69 V, FF= 0.66). This outcome was further validated using DFT calculation. DFT calculation suggested that the defect sites of Sn-perovskite would be effectively compensated by the PCBM coordination.
We would like sincerly thank NEDO.