Preventing Anion Exchange between Perovskite Nanocrystals by Confinement in Porous SiO2 Nanobeads

Yucong Su; Qiang Jing; Yue Xu; Xing Xing; Zhenda Lu

doi:10.1021/acsomega.9b03524

Preventing Anion Exchange between Perovskite Nanocrystals by Confinement in Porous SiO₂ Nanobeads

ACS Omega. 2019 Dec 11;4(26):22209-22213. doi: 10.1021/acsomega.9b03524. eCollection 2019 Dec 24.

Authors

Yucong Su¹, Qiang Jing¹, Yue Xu¹, Xing Xing¹, Zhenda Lu¹

Affiliation

¹ College of Engineering and Applied Sciences and Collaborative Innovation Center of Advanced Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University, Nanjing 210093, China.

Abstract

All-inorganic CsPbX₃ (X = Cl, Br, I) perovskite nanocrystals (NCs) are highly attractive due to their outstanding optical and electrical properties. However, poor stability and easy anion exchanges between CsPbX₃ nanocrystals with different halides limit their applications in light-emitting diodes (LEDs). To solve the problems, we developed an approach to in situ synthesize CsPbX₃ NCs into porous silica colloidal spheres, which can effectively prevent anion exchange and increase photo stability. Based on our results, we first proved that the anion exchange between CsPbX₃ nanocrystals is mainly driven by physical collision of the nanocrystals, not requiring a bridge such as a solvent. We subsequently used an optimized ratio of green, red, and blue SiO₂/CsPbX₃ composites as solid-state luminescent materials to fabricate single-layer white light-emitting diodes (WLEDs). No anion exchanges have been observed in the LED fabrication and lighting process.