Cubic CsPbI3 Nanoarchitectonics with High and Stable Photoluminescence toward White Light-Emitting Diodes

Abstract

The poor stability of cesium lead iodide (CsPbI3) perovskite nanocrystals (NCs) under light and humidity conditions limits their practical application. The dynamic binding of ligands is easy to desorb during the purification process, which results in a deterioration of their optical performance and stability. In this paper, sodium dodecyl benzene sulfonate (SDBS) was used to modify the surface of CsPbI3 NCs. By utilizing the strong combined effect of benzenesulfonic acid and Pb ions, the poor stability caused by the loss of weakly interacting amine ligands was effectively improved; meanwhile, the I ion vacancies can be filled to inhibit the occurrence of nonradiative recombination, so that the optical performance of the CsPbI3 NCs is improved. The radiative and nonradiative recombination process during photoluminescence is deeply discussed. After modification, the photoluminescence quantum yields of CsPbI3 NCs reached 90.7%, the superior photoluminescence intensity still retained 83% of the initial intensity after being stored for 60 days under environmental conditions, and the stability in water was remarkably improved. Additional SDBS was used after purification, suggesting that the presence of SDBS can effectively improve photostability. This method offers a new idea for preparing high-performance perovskite-based devices.