Illuminating the Nanoparticle Array: Unveiling the Interplay between Photodegradation and Aggregation Degree of CsPbBr₃ Nanocrystals

Abstract

All inorganic CsPbX 3 (X = Cl, Br, I) nanocrystals (NCs) have attracted significant attention because of their outstanding photoelectrical properties. However, the stability of CsPbX 3 NCs still poses a challenge for their practical applications due to the inherent ionic nature. Previous research has investigated the photodegradation of CsPbBr 3 NCs, but the exact structure−property correlation is still not very clear. Furthermore, whether the photodegradation is affected by the aggregation degrees of the CsPbBr 3 NCs has not yet been considered. Here, a robust strategy to fabricate the CsPbBr 3 NC array with varied aggregation degrees was developed through atomic force microscopy (AFM) nanoxerography. The number of CsPbBr 3 NCs in one spot of the array, noted as the aggregation degree, could be tuned by the corresponding surface potential values. Based on the precise positioning within the array system, each spot can be easily associated with on-site TEM characterization. In addition, photoluminescence intensity traces over time of each spot could be simultaneously measured under the same conditions. The statistical results clearly demonstrated that spots with higher aggregation degrees (25−60 NCs) exhibited a relatively slower decline rate, indicating higher photostability. These findings could provide valuable insights into the development of functional nanodevices based on CsPbBr 3 NCs.

Turn-on fluorescence humidity sensing based on Cs4PbBr6 nanocrystal array

“…Typically, we fabricated a nano-array of synthesized Cs 4 PbX 6 NCs on a substrate using modified AFM nanoxerography. 45–56 By arranging only dozens of Cs 4 PbX 6 NCs per spot, the nano-sensor exhibited significantly enhanced fluorescence sensitivity in specific humidity environments, enabling fast fluorescence response speed that initiated within one minute and stabilized in less than six minutes. Through statistical analysis of fluorescence changes in 10 × 10 spots (spot pitch: 5 μm), we established a working curve correlating these changes with different humidity levels.…”