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In this paper, the effects of CsPbIBr2quantum dots (QDs) of the same composition as perovskite films as interfacial layers on the stability, carrier dynamics, quality, and optical properties of perovskite films are investigated. CsPbIBr2films modified by CsPbIBr2QDs are prepared by two-step coating. Transmission electron microscopy (TEM) results show that the CsPbIBr2QDs are formed in a lattice pattern and the size is about 10 nm. Atomic force microscopy (AFM) and surface morphology analysis (SEM) results show that when the volume of the dripped QDs is 0.08 mL, the bulk film quality is the best. To further study the effect of the QD-modified CsPbIBr2film on the performance of PSCs, QD-modified and hole transport layer (HTL)-free all-inorganic carbon-based perovskite solar cells (PSCs) are prepared. The PCE results show that the stability and PCE of all-inorganic perovskite cells prepared with QDs as the interface layer are improved. The CsPbIBr2carbon-based PSC prepared at a QD volume of 0.08 mL shows the best performance, for which the PCE reached 7.36%, which is 10% higher than that prepared without QD modification. This work offers a method for facilitating contacts between QDs and bulk films to achieve the high efficiency and excellent stability of HTL-free carbon-based PSCs.

SnO2has gained wide attention because of its low synthesis temperature (approximately 150 °C), high electron mobility, and low manufacturing cost. However, the lattice mismatch at the SnO2/CsPbIBr2interface and the oxygen vacancy leads to nonradiative recombination. Therefore, the key to improving the performance is to remove the defects between the SnO2and the CsPbIBr2. In this paper, the first-principles calculation and experimental results show that the doping of LiF can enhance the conductivity of SnO2films and improve the energy band alignment at the SnO2/CsPbIBr2interface, which enhances interfacial carrier transport. Furthermore, the doping of LiF can adjust the lattice constants of the SnO2films and decrease the lattice mismatch between SnO2and CsPbIBr2. The results showed that the LiF-modified SnO2used at the optimum concentration had the best power conversion efficiency (PCE) based on SnO2:LiF/perovskite of 6.58%, which is nearly 34.83% higher than that of the pure CsPbIBr2perovskite solar cells (PSCs). This work provides an insightful strategy to improve the stability and efficiency of carbon-based all-inorganic CsPbIBr2PSCs.