Fluorinated hole transport material resistant to high annealing temperature applied in inverted perovskites solar cells

Abstract

A dopant-free and low-cost hole transport material (HTM) with dibenzo[b,d]thiophene as the center unit, bis(4-methoxyphenyl)amine as the terminal unit, and fluorine substitution adjacent to the methoxyl (named DBT-4F-MOP) is designed and applied in inverted organic-inorganic hybrid perovskite solar cells (OIH-PSCs). The synthetic cost of DBT-4F-MOP in the lab is just as low as 115 CNY/g, which is much lower than the benchmark HTM poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA, 2500 CNY/g). Due to the introduction of the fluorine atoms, the annealing temperature of the HTM can be increased by over 150 ℃. The highest efficiency of the inverted device based on it can reach 16.8 %, with an open circuit voltage of 1.04 V, a short circuit current of 21.57 mA cm−2, and a fill factor of 74.69 %, while the reference device based on PTAA can reach a PCE of 17.54 %. This work provides an avenue for the design of low-cost, dopant-free, and high-annealing temperature HTMs for inverted OIH-PSCs.