Constructing Heterostructural CsPbBr3-PbS Quantum Dots for High-Stability Solar Cells with Efficient Infrared Energy Harvesting

Inorganic perovskite quantum dots (PQDs) have become a research hotspot in recent years owing to their outstanding optoelectronic properties. Compared to CsPbI3, CsPbBr3 is valued for its higher thermal and phase stability and larger device open-circuit voltage. Herein, we report a synthetic strategy for heterostructural CsPbBr3-PbS QDs. Then, we successfully verify the formation of the heterostructures using transmission electron microscopy (TEM) and X-ray diffraction (XRD) measurements, in which the corresponding interplanar distance and a noticeable angular shift are observed due to the growth of PbS on CsPbBr3 QDs. As a result, the CsPbBr3 QDs are connected by the PbS QDs, and the Pb suspension bonds on the outer surface of the CsPbBr3 QDs are also passivated. This contributes to the high stability of the heterostructural CsPbBr3-PbS QD dispersion and solar cells. Moreover, taking advantage of the surface passivation and bridging, the heterostructural CsPbBr3-PbS QD solar cells show a significant improvement in the efficiency of the devices. This work might eventually provide a reference method for the construction of all-inorganic quantum dot heterostructures and open up an avenue for improving the stability of all-inorganic CsPbX3 nanocrystals for use in photovoltaic and displays.