A novel in-situ process for high performance blue CsPbBr3 perovskite quantum dots via Cs ion-exchange in Sodium Titanium Silicate

Abstract

Inorganic perovskite quantum dots (QDs) have attracted extensive attention from researchers in recent years, because of their good prospects in micro-LED for next generation lighting and display. However, the research on high quality and stable inorganic perovskite blue QDs is relatively backward, which limits its further applications in micro-LED. In the present work, crystalline silicotitanate (CST) is used as matrix and synthesized by hydrothermal method, then, Cs+ ion replaces Na+ ion in the tunnel in c-axis dimension of CST matrix by ion exchange, and finally, the CsPbBr3 QDs are in situ anchored on the Cs+ ion in the tunnel. The sizes of the as prepared CsPbBr3 QDs are determined to be mostly less than 4 nm, which guarantees the as prepared CST: CsPbBr3 QDs to have a brilliant blue emission peak at 463 nm with a narrow FWHM of less than 20 nm, and it can be excited by a broad n-UV light range from 300 to 400 nm and peak at 365 nm. A photoluminescent quantum yield of 88.34% is achieved. Furthermore, the as prepared CST: CsPbBr3 QDs is demonstrated to have a good air and thermal stability with an average PL lifetime of 112.00 ns? The color gamut of CST: CsPbBr3 QDS together with the commercial green (Sr, Ba)2SiO4: Eu2+ and red (Sr, Ca)AlSiN3: Eu2+ phosphors is calculated to be 114.12% of the NTSC standard. Therefore, the present pure blue CST: CsPbBr3 QDs can be a potential backlight source for display devices.