Size modulation and heterovalent doping facilitated hybrid organic and perovskite quantum dot bulk heterojunction solar cells

Organic photovoltaics and halide perovskite solar cells are both solution-processable third-generation photovoltaic devices (PVs) attracting enormous research attention. In this study, we demonstrate a hybrid organic and perovskite PV device by mixing all-inorganic CsPbI₃ quantum dots (QDs) into the conventional organic bulk heterojunction active layer of PBDB-T:IT-M. It is found that the charge transfer properties between QDs and organic donor/acceptor interfaces can be fine-tuned with the size modulation and the heterovalent bismuth (Bi) doping of perovskite QDs, leading to an increase in open-circuit voltage. In addition, the incorporation of perovskite QDs with different sizes could effectively modify the nanoscale bulk heterojunction morphology toward more efficient charge collection and thus a higher fill factor. The photocurrent of the devices can also be improved through Rayleigh scattering and light absorption of the QDs. As a result, a noticeable enhancement in device performance has been achieved by the PBDB-T:IT-M with 10 nm Bi-doped CsPbI₃ QD device. This work provides one feasible route to fine-tune the energy level alignment and nanophase separation by integrating these two promising PV materials.