摘要： CsPbX3 (X= Cl, Br, I) inorganic perovskite nanocrystals (PNCs) not only maintain the excellent optical and electronic properties of bulk material but also possess the features of nano-materials, such as tunable bandgap, easily processable colloidal ink, enable them to be suitable for incorporation into various electronic devices and compatible with printing techniques. In contrast to the traditional II-VI and III-V semiconductor nanocrystals, the unique defect-tolerance effect makes the CsPbX3 PNCs very promising materials for optoelectronic applications. The ligands around the NCs play a critical role on the optoelectronic devices performance. Here, through a facile hexane/ethyl acetate (MeOAc) solvent treatment method to control the ligand amount around the CsPbBrI2 PNCs, we systematically demonstrated the impact of ligand amount on the performance of solar cell devices and first quantify the ligand amount precisely by nuclear magnetic resonance (NMR) internal standard method. Through controlling the ligand amount, the film quality, charge transfer and transport properties are largely improved. In addition, a simple annealing process is applied to improve the interface properties by partial crystal fusion. As a consequence, the photovoltaic power conversion efficiency (PCE) of 12.2% is achieved by employing a n-i-p device structure, which is the highest performance of mixed-halide CsPbX3 NCs solar cells. This work emphasizes the important role of ligand amount on the NCs device performance.