Phenoxazine‐benzimidazolium ionic hole transport material for perovskite solar cells

Abstract

A novel organic ionic material, hole transport material‐1 (HTM‐I), was synthesized and characterized as a hole transport material for perovskite solar cells (PSCs), with the aim of replacing 2,2',7,7'‐Tetrakis[N,N‐di(4‐methoxyphenyl)amino]‐9,9'‐spirobifluorene (Spiro‐OMeTAD). HTM‐I was designed to incorporate both phenoxazine and benzimidazolium iodide salt structures, and its chemical structure was confirmed using 1H NMR and high‐resolution mass spectrometry. Differential scanning calorimetry measurements revealed that HTM‐I maintained an amorphous phase throughout the temperature range of −60 – 200 °C, and thermogravimetric analysis showed good thermal stability up to 220 °C. To evaluate its potential as a hole transport layer, perovskite solar cells were fabricated using a fluorine‐doped tin oxide (FTO)/compact‐TiO2/(Cs/FA/MA)Pb(I/Br)3/hole transport layer/Au configuration. The resulting n–i–p planar structure exhibited a power conversion efficiency of 10.4%.

Enhancing Surface Modification and Carrier Extraction in Inverted Perovskite Solar Cells via Self-Assembled Monolayers

“…These free carriers are then transported through the ETL and HTL, respectively, to the external electrode [ 7 ]. As for HTLs, molecular layers based on organic or conductive polymers have been widely studied to enhance the efficiency of PSCs [ 8 ]. However, these types of HTL layers have notable limitations in terms of reliability due to their environmental sensitivity [ 9 , 10 , 11 ].…”

Sequential‐dip‐coating processed mixed organic and inorganic perovskite film from halide‐free lead precursor for efficient perovskite solar cells

“…1,2 Recent advancements, including improved fabrication techniques, interface engineering, crystallization, and phase durability and stability methods, have propelled PrSCs to the forefront of effective solution-processed photovoltaic technologies. [3][4][5] Notably, the utilization of organic materials like alkylammonium lead halides, (RNH 3 )PbX 3 (R = alkyl, X = Cl, Br and I), synthesized via reactions with lead sources (PbX 2 ) and formamidinium iodide (FAI) or methylammonium iodide (CH 3 NH 3 I, MAI), demonstrates excellent photo-sensitization and electron/hole transport properties. 6 Perovskite materials, specifically those based on single-cation and anionic ligands, for example, MAPbI 3 and FAPbI 3 , have found application as light harvesters in PrSCs as a result of their broad light absorption spectrum, lower exciton binding energy, suitable optical bandgap, and efficient chargecarrier transportation.…”