CsPbX₃ Quantum Dots Embedded in Zeolitic Imidazolate Framework-8 Microparticles for Bright White Light-Emitting Devices

Abstract

CsPbX3 perovskite quantum dots (QDs) have been receiving extensive attention in the fields of luminescence and photovoltaics. However, the bad stability of the CsPbX3 QDs limited their practical applications because of the inevitable factors including light, heat, and humidity. In this paper, a mechanical chemical synthesis method with no organic solvent (oleylamine and oleic acid) addition was used to grow inorganic CsPbX3 (X = Cl, Br, and I) QDs in situ in the hole of zeolitic imidazolate framework-8 (ZIF-8), thus improving the stability and resistance to ion exchange of CsPbX3 QDs. Due to the presence of CsPbX3 QDs in ZIF-8, the QDs were protected by the ZIF-8 matrix to impede luminescence degradation. The photoluminescence (PL) quantum yields of CsPbCl3/ZIF-8, CsPbBr3/ZIF-8, and CsPbI3/ZIF-8 composites were 51, 72, and 57%, respectively. Compared with the initial CsPbX3 QDs, the CsPbX3/ZIF-8 composites exhibited narrower emission spectra and stable PL, which can be maintained for 75 days under atmospheric conditions. The QDs with blue, green, and red emissions were created by controlling synthesis conditions. A green light-emitting diode (LED) with Commission Internationale de I′Eclairage (CIE) coordinates of (0.130, 0.746) and a white LED with CIE coordinates of (0.297, 0.299) were obtained. The lumen efficiency of the white LED device is 11.5 lm/W. ZIF-8 matrix encapsulation greatly improves the stability of CsPbX3 QDs, which makes them attractive in LED and optoelectronic device-related applications.