Triphenylamine-Appended\nCarbazole-Based Hole-Transport\nLayer for Perovskite Solar Cells Fabricated under Low Humidity

Perovskite solar cells (PSCs), renowned for their high\npower conversion\nefficiency (PCE), have organic–inorganic metal halide perovskites\n(OIMHPs), hole-transport materials (HTMs), and electron-transport\nmaterials (ETMs) as crucial components determining their performance\nand cost. Materials like spiro-OMeTAD and PTAA, which are widely employed\nas HTMs in high-efficiency PSCs, have difficult synthesis routes,\nlow yields, and limited precursor availability. This results in high\ncosts, which make them unsuitable for large-scale applications. This\nstudy explores the synthesis and fabrication of PSCs using a carbazole-based\nHTM, CBZ-BDMTPA, a 2,7-dimethoxytriphenylamine-appended carbazole,\nwhich has been successfully synthesized indigenously, ensuring both\ncost-effectiveness and better production yield compared to conventional\nHTMs. The synthesized HTM revealed absorption in the near-ultraviolet\nregion, low oxidation potentials, and better thermal stabilities than\nsimilar HTM analogues. The PSCs fabricated under 10% humidity exhibited\na PCE of 14.04%, similar to that of the reference devices fabricated\nwith spiro-OMeTAD (14.5%). This ensures CBZ-BDMTPA as a promising\nalternative to the costlier high-performing HTM. Moreover, a peak\nexternal quantum efficiency of 80% ensured efficient charge collection\nby CBZ-BDMTPA.