α-CsPbI3 Colloidal Quantum Dots: Synthesis, Photodynamics, and Photovoltaic Applications

Owing to their defect tolerance and phase stability, α-CsPbI3 colloidal quantum dots (CQDs) with high mobility and 80–95% photoluminescence quantum yield (PLQY) are promising candidates for next-generation photovoltaics (PVs). Recently, α-CsPbI3 CQD PVs have begun to show promising power conversion efficiencies of 13.4%, with the open-circuit voltage approaching the Shockley–Queisser limit. These devices are stable in ambient conditions for several months. However, the short-circuit current density (JSC) of ∼12 mA/cm2 is low, and the limiting mechanisms are unclear. In this work, we review the strategies for improving the JSC and the effect of interfaces and mobility of the charge transport layers on carrier extraction. We also evaluate strategies to enhance the stability of CsPbI3 CQDs under illumination, as well as methods to elucidate the recombination losses in the CQD PVs and methods to reduce these losses. This work provides routes to achieve efficient and stable α-CsPbI3 CQD PVs.