Efficient Perovskite\nSolar Cells via Phenethylamine\nIodide Cation-Modified Hole Transport Layer/Perovskite Interface

Abstract

Perovskite solar cells (PeSCs) were fabricated by using\nCs_<i>x</i>FA_1–<i>x</i>PbI_3–<i>x</i>Cl_<i>x</i> as\nthe photoactive layer, and the effects of different proportions of\ncesium chloride (CsCl)/formamidinium iodide on perovskites were investigated.\nCesium (Cs) can stabilize the α phase of the perovskite, while\nchlorine (Cl) can increase the size and crystallinity of perovskite\ncrystals and reduce non-radiative cladding, thereby improving the\nperformance of the overall device. The maximum power conversion efficiency\n(PCE) measured for Cs_0.2FA_0.8PbI_2.8Cl_0.2-based PeSCs was 18.9%. To further improve the photovoltaic\ncharacteristics of PeSCs, Cs_0.2FA_0.8PbI_2.8Cl_0.2-based PeSCs were introduced into different\nconcentrations of phenethylammonium iodide (PEAI) to modify the interface\nbetween the NiO_<i>x</i> hole transport layer\n(HTL) and the perovskite photoactive layer, which can simultaneously\npromote excellent crystallinity of the perovskite layer and passivated\ninterfacial defects, reducing recombination near the perovskite/HTL\ninterface in PeSCs, thereby increasing the efficiency of the device.\nCompared with the control Cs_0.2FA_0.8PbI_2.8Cl_0.2-based PeSC, the PCE of PeSC with the PEAI\n(10 mg/mL)-modified NiO_<i>x</i>/perovskite interface\nincreased significantly from 18.9 to 20.2%.