Dual-Functional-Polymer Dopant-Passivant Boosted Electron Transport Layer for High-Performance Inverted Perovskite Solar Cells

摘要

Herein, the use of the polymer poly([N,N′-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5 ′-(2,2 ′-bithiophene)) (PNDI-2T) as botha dopant in the [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) electrontransport layer (ETL) of inverted perovskite solar cells (PSCs) and a surfacepassivant on the perovskite layer is reported. The PNDI-2T doping is found to becrucial for improving the homogeneity of the ETL film with complete surfacecoverage, enhancing the electron mobility of the ETL, and promoting the energylevel match between the perovskite and ETL, thereby significantly facilitatingelectron transport in the PSC devices. Furthermore, as a passivant, the PNDI-2Tin the ETL tends to pin on the top surface of the perovskite layer via Pb-Scoordination. The surface passivation is also beneficial for the suppression of ionmigration and diffusion of metal species from the electrodes. In consequence,PSCs with the PCBM:PNDI-2T ETL reached an efficiency of 21.13% and retain90% of their original performance after 860 h light soaking. This work will inspirenew efforts to take advantage of multifunctional ETLs as a simple and effectivemethod to enhance the performance and long-term stability of PSCs.