Fused Dithienopicenocarbazole Enabling High Mobility Dopant-Free Hole-Transporting Polymers for Efficient and Stable Perovskite Solar Cells

As a critical component in perovskite solar cells (PSCs), hole-transporting materials (HTMs) have been extensively explored. To develop efficient dopant-free HTMs for PSCs, a decent hole mobility (>10(-3) cm(2) V-1 s(-1)) is critically essential, which is, however, seldom reported. In this work, we introduce two novel donor-acceptor (D-A) type conjugated polymers (PDTPC-1 and PDTPC-2) with narrow bandgap unit, i.e., fused dithienopicenocarbazole (DTPC), as the donor building block and benzo[c][1,2,5]thiadiazole derivatives as the acceptors. The highly planar and strong electron-donating DTPC endows the polymers with superior hole mobility up to similar to 4 x 10(-3) cm(2) V-1 s(-1). Because of the better energy alignment with perovskite and excellent film-forming property, PSCs with PDTPC-1 as HTM show an appreciably enhanced PCE of similar to 17% in dopant-free PSCs along with improved device stability as opposed to PDTPC-2. Our work revealed for the first time that the introduction of narrow bandgap DTPC in D-A polymers could achieve remarkably high hole mobility in the pristine form, favoring the application in dopant-free PSCs.

Automated summary

This study introduces two novel donor-acceptor conjugated polymers with excellent hole mobility and superior PCE for the application in dopant-free PSCs, providing a new approach for improving device performance.