Abstract
The optimized electron transport layer (ETL) plays a crucial role in the practical application of polymer solar cells (PSCs). Herein, bio-inspired polydopamine (PDA) modified Ti3C2Tx (PDA-Ti3C2Tx) as a multifunctional additive is dispersed into ZnO to fabricate ZnO:PDA-Ti3C2Tx composite ETL. PDA-Ti3C2Tx passivates the trap states of ZnO via forming strong and stable chelate interactions through Zn2+ ions and PDA molecules. PDA-Ti3C2Tx also lowers the vacuum level of transport layer by forming interface dipoles between catechol of PDA and Zn2+ ions of zinc oxide. Moreover, PDA-Ti3C2Tx constructs additional electron transport pathways by connecting the discontinuities among ZnO nanocrystals. As such, ZnO:PDA-Ti3C2Tx composite ETL, with higher conductivity and proper work function, can effectively collect electrons in the PSCs. Compared with ZnO control devices, the performance of PSCs with ZnO:PDA-Ti3C2Tx ETL is obviously enhanced with power conversion efficiencies (PCEs) from 10.34% to 12.07% based on PBDB-T:ITIC, 14.84–16.69% based on PM6:Y6, and 8.14–9.41% for PTB7:PC71BM, respectively. The ambient stability of the PSCs with ZnO:PDA-Ti3C2Tx ETLs is significantly improved due to the increased hydrophobicity of ETL and the enhanced crystallinity of active layer. The novel ETLs provide a facile, eco-friendly, low-cost approach to realize the highly performance and stable PSCs.
NSTL
Elsevier