Synergistic Optimization of Minimal Antisolvent Processing and Dopant-Free HTMs for High-Efficiency Perovskite Solar Cells

Abstract

Over a span of approximately 15 years, perovskite solar cells (PSCs) have achieved remarkable improvements in performance, increasing from 3.8% to 26.1%. Research is underway aiming to eliminate the use of anti-solvents to form the perovskite layers or substitute them with environmentally friendly solvents. Additionally, extensive developments have occurred in using conjugated structures as hole transport materials (HTMs) to replace 2,2′,7,7′-tetrakis(N,N′-di-p-methoxyphenylamine)-9,9′-spirobifluorene (Spiro-OMeTAD) because of the high cost of synthesis and its low conductivity. In this study, the amount of anti-solvent is reduced successfully to 8 μL, less than 3% of the conventional anti-solvent amount (300 μL). This result is produced by combining the displacement of dimethyl sulfoxide (DMSO) with N-methyl-2-pyrrolidone (NMP) and the presence of moisture during fabrication. Furthermore, dopant-free HTMs is newly synthesized based on monovalent cations on carbazoles. The combination of the small anti-solvent procedure with novel HTMs facilitates PSCs achieving a power conversion efficiency exceeding 20%. This result demonstrates the superior photoelectric properties of the method, attributable to enhanced reproducibility and electrical stability.