Dimension Tuning And Component Engineering Of Key Materials For Efficient And Stable Inverted Perovskite Solar Cells

Organic-inorganic hybrid perovskites have attracted intensive attention due to their unique material properties,such as tunable bandgaps,superior light absorption coefficient and ease of processing.In recent years,lots of perovskite works have been reported in photovoltaics,light-emit-ting diodes and photodetectors,etc.However,the instinct defects at the perovskite grain boundaries,and the charge accumulation at the carrier transport layer/perovskite interface are detrimental to the performance of perovskite solar cells(PSCs).Here,dimension and component engineering were applied to modify the perovskite active layer and to adjust hole transport layers(HTLs)for highly efficient and stable planer inverted(p-i-n)PSCs.(1)Dimension regulation of the perovskite active layer: A stable and low defect onedimensional(1D)cross-linked metal-halide materials was designed.Heterogeneous perovskites were formed by regulating the stoichiometric ratio of 1D cross-linked leadiodide and three-dimensional(3D)perovskite.Based on the lewis acid-base interactions between the organic component 1,2-bis(diphenylphosphino)ethane dioxide(DPPO)in the1 D cross-linked lead-iodide adduct and the inorganic component lead iodide in the 3D perovskite,the 1D materials were selectively distributed at the grain boundaries(GBs)of the perovskite crystals,which efficiently passivated imperfections in polycrystalline films of perovskite and suppressed ion migration in devices.The p-i-n device on 1D/3D heterogeneous perovskite showed a power conversion efficiency(PCE)of 20% with a high tolerance towards the environment(light,heat,humidity,and oxygen).(2)Components regulation of hole transporting materials: Based on excellent electrical characteristics and chemical stability of the p-type nitroxide radical polymer poly(4-epoxypropyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl radical)(PTEO),the hybrid HTLs were prepared by mixing the poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine](PTAA)with PTEO.Hole extraction and transport were remarkably enhanced,and the electrical robustness and contact at the PTAA/perovskite interface were significantly improved.PTEO/PTAA hybrid HTLs boost the PCE of inverted PSC devices to 21%.The unencapsulated device retained 79% of its initial performance condition for continuous light aging for 500 h.