Efficient protection of perovskite nanoparticles in salicylic acid hollow crystal via super simple standing method

Cesium lead bromide (CsPbBr₃) perovskite nanoparticles (NPs) are widely recognized for their high potential for next-generation optoelectronic devices. However, these NPs’ conventional surface-capped organic ligands with high fluidity are frequently shed from particles during separation and purification steps, significantly reducing their stability. Therefore, a simple method to improve the strength of perovskite NPs is essential. Here, we utilized salicylic acid (SA), which acts as a ligand and protective coating of luminescent NPs, to create CsPbBr₃@SA crystals using a straightforward standing technique. The CsPbBr₃ NPs were perfectly encapsulated and size-limited in the SA hollow space needle-shaped crystals that retain their significant optical intensity. The fluorescence emission intensity of CsPbBr₃@SA crystals without additional treatment can be maintained for six weeks under normal ambient conditions, demonstrating the SA ligand’s ability to protect CsPbBr₃ NPs better. Furthermore, the green emission CsPbBr₃@SA crystals are combined with K₂SiF₆ red phosphor and packed with a commercially available blue light emitting diode (LED) chip to fabricate a high gamut area white LED device. The highly straightforward standing method successfully enables the high-potential preparation of perovskite nanoparticles for future practical applications.