Solvent Evaporation Induced Large-Scale Synthesis of Cs₄PbBr₆ and CsPbBr₃ Microcrystals: Optical Properties and Backlight Application for LEDs

Abstract

The contemporary work focuses on embossing the emissive nature of lead halide perovskite materials, specifically Cs 4 PbBr 6 microcrystal powder prepared via single step bulk recrystallization method followed by the solvent evaporation route from gram to kilogram scale. The X-ray diffraction pattern confirms the formation of phase pure Cs 4 PbBr 6 with a goodness of fit value of 1.51 calculated from Rietveld refinement and the fluorophore powder manifesting an intrinsic band gap of 3.76 eV. The experimental yield of 99.4% indicates the absence of any unreacted precursors. The fabricated flexible, free-standing Cs 4 PbBr 6 @PMMA film encompassed better moisture stability without undergoing phase transitions for 400 days. The temperature-dependent photoluminescence spectra denote that 51% of the intensity was retained when cooled back to room temperature after heating it till 180 °C. Moisture studies at two extreme humidity conditions also reveal the appreciable stability of the fluorophore film against moisture. The stability studies with respect to UV irradiation substantiate that the film retained its stability even after exposing it continuously to UV radiation for seven days. The outstanding optical properties of these microcrystals, owing to the higher exciton binding energy, make them a promising candidate as excellent fluorophores for color conversion, backlight, and light-emitting applications. The Cs 4 PbBr 6 @PMMA film was employed as the top cover of a commercial blue LED, producing a robust green emission which revealed its possible application as a phosphor material.

Improved photoluminescence stability and defect passivation in SbBr3 post‐treated CsPbBr3 quantum dots under ambient conditions

“…Moreover, to check the temperature dependence on the stability of the QDs, the solutions were heated from 30 to 80°C, and PL spectra were taken immediately. Both the solutions followed the trend of reduction in PL intensity with an increase in temperature due to increased non‐radiative recombination dominating over the radiative recombination rates [13]. Figure 8d shows the PL spectra comparison for both samples after heating the solutions at 50°C.…”

“…Recently, there has been much interest in all inorganic cesium lead halide perovskite (CsPbBr 3 where X = Cl, Br, I) quantum dots (QDs) as active components for optoelectronic devices such as photodetectors [1–6], solar cells [7–9], light‐emitting diodes [10–14] (LEDs), and display devices [15, 16]. High photoluminescence (PL) quantum yield (PLQY), size‐tunable bandgap, narrow emission peak, and excellent colour purity are some of the unique features of cesium halide perovskites [17].…”

High-speed space optical communication based on metal halide perovskite single crystals

“…3b). 36 In Fig. 3c, the PL intensity of Cs 4 PbBr 6 SCs is recorded over 1.5 hours under continuous excitation from a LD.…”

Synthesis of Mn2+:CsPb (Br1−xClx)3perovskite quantum dots in an ambient atmosphere: stability analysis and self-powered photodetector applications

“…1,2 These properties paved the way for their application in light emitting diodes (LEDs), 3,4 photodetectors, 5,6 lasers, and solar cells. 7,8 At first, the organometal halide perovskite QDs gained greater interest because of their low cost, broad absorption, and tunable PL emission 9 over the entire visible spectrum. 10 Despite the excellent optoelectronic properties shown by organometallic halide perovskites, they still suffer stability threats against humidity and heat of the external environment.…”