Efficient Hole-Transporting Materials with Triazole Core for High-Efficiency Perovskite Solar Cells

Abstract

Efficient hole-transporting materials (HTMs), TAZ-[MeOTPA](2) and TAZ-[MeOTPATh](2) incorporating two electron-rich diphenylamino side arms, through direct linkage or thiophen bridges, respectively, on the C3- and C5-positions of a 4-phenyl-1,2,4-triazole core were synthesized. These synthetic HTMs with donor-acceptor type molecular structures exhibited effective intramolecular charge transfer for improving the hole-transporting properties. The structural modification of HTMs by thiophene bridging might increase intermolecular - stacking in the solid state and afford a better spectral response because of their increased -conjugation length. Perovskite-based cells using TAZ-[MeOTPA](2) and TAZ-[MeOTPATh](2) as HTMs afforded high power conversion efficiencies of 10.9% and 14.4%, respectively, showing a photovoltaic performance comparable to that obtained using spiro-OMeTAD. These synthetically simple and inexpensive HTMs hold promise for replacing the more expensive spiro-OMeTAD in high-efficiency perovskite solar cells.