High-Performance All-Polymer Solar Cells and Photodetectors Enabled by a High-Mobility n-Type Polymer and Optimized Bulk-Heterojunction Morphology

All-polymer solar cells (all-PSCs) and all-polymer photodetectors (all-PPDs) are promising for application in flexible electronics, but their performance is greatly limited by the lack of polymer acceptors and the difficulties in morphology control. Herein, we report the use of a high-mobility n-type polymer semiconductor, PNDI-DTBT, for fabricating high-performance all-PSCs and all-PPDs. By pairing PNDI-DTBT with a matched polymer donor, a prominent power conversion efficiency of 8.5% was obtained in all-PSCs, demonstrating the great potential of high-mobility n-type polymers with a conventional donor-acceptor skeleton for photovoltaic application. Moreover, all-PPDs with a low dark current density of 1.32 x 10(-8) A cm(-2) at -0.1 V bias and a high specific detectivity of 4.77 x 10(12) Jones were achieved, which belong to the best results of organic photodetectors. Morphology investigations revealed that the formation of a bicontinuous interpenetrating network with optimal phase separation scale, high domain purity, and preferential vertical composition distribution in the bulk-heterojunction active layer contribute to the remarkable device performance. These results suggest that combining high-mobility n-type polymers and morphology optimization is fruitful to achieving high-performance all-PSCs and all-PPDs.

Automated summary

This study demonstrates the fabrication of high-performance all-polymer solar cells and photodetectors using a high-mobility n-type polymer semiconductor, PNDI-DTBT. By combining PNDI-DTBT with a matched polymer donor, significant power conversion efficiency and excellent device performance were achieved. Morphology optimization in the bulk-heterojunction active layer played a crucial role in enhancing the device performance of the all-PSCs and all-PPDs.