Suppressing Nonradiative Recombination by Electron-Donating Substituents in 2D Conjugated Triphenylamine Polymers toward Efficient Perovskite Optoelectronics
Lili Xu, Haifeng Zheng, Bo Xu, Gaoyu Liu, Shengli Zhang, Haibo Zeng
Abstract
Highly efficient perovskite optoelectronics (POEs) have been limited by nonradiative recombination. We report a strategy to inhibit the nonradiative recombination of 2D triphenylamine polymers in the hole transport layer (HTL) via introducing electron-donating groups to enhance the conjugation effect and electron cloud density. The conjugated systems with electron-donating groups present smaller energy level oscillation compared to the ones with electron-absorbing groups, as confirmed by nonadiabatic molecular dynamics (NAMD) calculation. Further study reveals that the introduction of low-frequency phonons in the electron-donating group systems shortens the nonadiabatic coupling and inhibits the nonradiative recombination. Such electron-donating groups can decrease the valence band maximum of 2D polymers and promote hole transport. Our report provides a new design strategy to suppress nonradiative recombination in HTL for application in efficient POEs.