Dual‐Site Passivation for Bright and Stable Blue‐emitting CsPbBr₃ Nanoplatelets

Abstract

Blue‐emitting perovskite nanocrystals (NCs) are important components of high‐definition display device, but their instability to light and moisture severely hinders the commercial application. Here, a dual‐site passivation strategy is proposed and the halogen–halogen bond to surface capping molecules is applied. The bi‐functional molecule with a fluorine group and carboxyl group on the phenyl ring, would form a shell‐like molecular structure covering the nanocrystal surface at halogen and lead site via halogen‐halogen bond and coordination effect, respectively. Considering the binding strength and acid dissociation constant of several fluoro acids, the optimal optical properties and film stability confirm the para‐fluorobenzoic acid molecule provides the most effective protection for initial perovskite products account for their stronger anchoring affinity and more comprehensive surface coverage. Consequently, this work sheds light on the molecular functionality and configuration are crucial for surface properties of perovskite NCs.

Surface co-modification enabling efficient and spectrally stable mixed-halide blue light-emitting diodes

“…Generally, blue emission can be achieved by modulating the quasi-two-dimensional (quasi-2D) quantum well distribution, enhancing the quantum confinement effect of CsPbBr 3 , or doping Cl species to change the degree of orbital overlap, respectively. 11–20 In recent years, there has been a significant focus on developing blue PeLEDs based on the first two techniques. However, it is reported that low-dimensional perovskites exhibit inefficient energy transfer, spectral broadening and even multi-peak emission owing to their complicated phase distribution.…”