Synthesis and spectroscopic characterization of CsPbBr3/Cs4PbBr6 perovskites synthesized via the microwave-assisted heating process for backlight display devices

Abstract

In this study, CsPbBr3/Cs4PbBr6 composites were prepared via microwave-assisted (MA) and conventional heating (CH) routes. X-ray diffraction and high-resolution transmission electron microscopy confirmed the coexistence of CsPbBr3 and Cs4PbBr6 phases in the prepared samples. The steady-state absorption spectra of the synthesized perovskites exhibited excitonic peaks at 310 and 525 nm because of the absorption of Cs4PbBr6 and CsPbBr3, respectively. The prepared samples exhibited characteristic emission peaks at approximately 523 nm. The MA-derived sample exhibited high color purity (94%), high quantum yield (89%), and good thermal stability (>98% after 100 h of treatment). By contrast, the CH-derived sample exhibited low color purity (91%) and quantum yield (70%). Furthermore, microwave irradiation with polar molecules in MA heating resulted in the rapid generation of homogeneous heat within the heated materials, which induced the substantial nucleation and growth of CsPbBr3. This phenomenon enhanced intensity of photoluminescence emission. The MA-derived sample exhibited a shorter excitonic lifetime (20 ns) than the CH-derived sample did (32 ns) because the MA-derived sample had less nonradiative trap sites. The color gamut of the as-prepared light-emitting devices fabricated with the MA-derived sample was 125% of the NTSC. This study indicated that the incorporation of microwave heating in the synthesis process is an effective approach for preparing CsPbBr3/Cs4PbBr6 composites with a wide color gamut, good thermal stability, and a PLQY. ? 2021 Elsevier B.V.