Solution-processed ITO nanoparticles as hole-selective electrodes for mesoscopic lead-free perovskite solar cells

Abstract

Carbon-based mesoscopic perovskite solar cells (PSCs) are promising for printable next-generation photovoltaic applications, but the optical properties of their carbon layer limit their light harvesting efficiency. We developed solution-processable indium-tin-oxide (ITO) nanoparticles to replace carbon electrodes for mesoscopic lead-free tin-based PSCs. The ITO electrodes were fabricated via screen printing with 1, 2, 4, 6 and 8 layers corresponding to the thicknesses of 2.1–14.3 μm; tin perovskite (GA_0.2FA_0.8SnI₃) with SnF₂ (20%) and EDAI₂ (15%) (GA represents guanidinium; EDAI₂ represents ethylenediammonium diiodide) was drop-casted on the device to produce a mesoporous structure of FTO/TiO₂/perovskite/Al₂O₃/ITO. The best device achieved a power conversion efficiency of 5.4% with great stability. These solution-processed ITO electrodes are a landmark to shed light on new paths for the commercialization of lead-free PSCs.