Hybrid Quantum Dot/Organic Heterojunction: A Route to Improve Open-Circuit Voltage in PbS Colloidal Quantum Dot Solar Cells

We have successfully demonstrated the effect of a thin organic bulk-heterojunction (BHJ) interlayer on improving the photovoltaic performance of lead sulfide (PbS) colloidal quantum dot (CQD) solar cells. Multiple organic BHJ films with PTB7-Th blending with various N-type acceptors have been introduced as hole-transporting layer (HTL) in PbS solar cells. Significant enhancement in Voc was achieved in the hybrid devices compared to devices based on conventional HTLs like 1,2-ethanedithiol-treated PbS. Systematic characterizations reveal that the hybrid CQD/organic BHJ architecture can effectively modulate the interfacial charge dynamics and lead to enhanced external quantum efficiency, resulting in a champion efficiency of 12.02%. Solution-processed hybrid CQD/organic architecture may become a universal approach to improve the photovoltaic performance and scalability of PbS CQD solar cells.