Giant Stability Enhancement of CsPbX₃ Nanocrystal Films by Plasma-Induced Ligand Polymerization

Abstract

All-inorganic CsPbX 3 (X = Cl, Br, and I) nanocrystals (NCs) are emerging as attractive semiconductor materials because of their outstanding optical properties. The low resistance of CsPbX 3 NCs to light, heat, oxygen, and water has been recognized as a major obstacle to their practical applications. Here, we demonstrate that the stability of CsPbX 3 NC films can be dramatically enhanced by Ar plasma treatment. It is revealed that plasma irradiation can induce ligand polymerization in the NC films if the ligands contain unsaturated carbon bonds. The ligand polymerization leads to encapsulation of the NCs in the ligand polymers. Because of the precise localization of the in situ ligand polymerization under plasma irradiation and the high NC content in the films without extra additives, the polymerized area can be precisely defined down to several micrometers. This enables easy fabrication of high-resolution NC pixels for next generation displays.

Recent Advances in Ligand Design and Engineering in Lead Halide Perovskite Nanocrystals

“…[ 363 ] Enhanced stability of the films fabricated with as‐synthesized LHP NCs has also been demonstrated through polymerization of the double bonds on the already‐present OA and OAm ligands (Figure 11I). [ 364 ] This could be achieved by mild plasma irradiation, a process that could be precisely controlled to form patterns (Figure 11J,K). [ 364 ] Effects of oxygen plasma treatment on the native organic ligand shells for both CsPbX 3 and MAPbX 3 NCs have also been explored.…”

“…[ 364 ] This could be achieved by mild plasma irradiation, a process that could be precisely controlled to form patterns (Figure 11J,K). [ 364 ] Effects of oxygen plasma treatment on the native organic ligand shells for both CsPbX 3 and MAPbX 3 NCs have also been explored. [ 365 ] Specifically, the O 2 plasma mainly affects the top few nanometers of the NC film and is able to partially remove residual organics (ligands) that could be detrimental to device performances.…”

“…I-K) Reproduced with permission. [364] Copyright 2019, American Chemical Society. at 100 °C, some of the ligands were removed, while annealing at 150 °C led to a coalescence of the NCs.…”

“…The diameter of each dot is 1 mm. I-K) Reproduced with permission [364]. Copyright 2019, American Chemical Society.…”

Recent Progress in CsPbX3 Perovskite Nanocrystals for Enhanced Stability and Photocatalytic Applications

“…prepared a CsPbBr 3 NCs‐PMA composite by embeding CsPbBr 3 NCs in PMA matrix, and the composite displayed excellent colloidal stability in aqueous media and exhibited higher photoluminescence properties [75] . In addition, encapsulation of CsPbX 3 NCs in plasma induced ligand polymerization to form core‐shell structure can also help to enhance the stability of CsPbX 3 NCs [76] …”