Highly Stable and Photoluminescent CsPbBr3/Cs4PbBr6 Composites for White-Light-Emitting Diodes and Visible Light Communication

Abstract

Inorganic lead halide perovskite is one of the most excellent fluorescent materials, and it plays an essential role in high-definition display and visible light communication (VLC). Its photochromic properties and stability determine the final performance of light-emitting devices. However, efficiently synthesizing perovskite with high quality and stability remains a significant challenge. Here, we develop a facile and environmentally friendly method for preparing high-stability and strong-emission CsPbBr3/Cs4PbBr6 composites using ultrasonication and liquid paraffin. Tuning the contents of liquid paraffin, bright-emission CsPbBr3/Cs4PbBr6 composite powders with a maximum PLQY of 74% were achieved. Thanks to the protection of the Cs4PbBr6 matrix and liquid paraffin, the photostability, thermostability, and polar solvent stability of CsPbBr3/Cs4PbBr6-LP are significantly improved compared to CsPbBr3 quantum dots and CsPbBr3/Cs4PbBr6 composites that were prepared without liquid paraffin. Moreover, the fabricated CsPbBr3/Cs4PbBr6-LP-based WLEDs show excellent luminescent performance with a power efficiency of 129.5 lm/W and a wide color gamut, with 121% of the NTSC and 94% of the Rec. 2020, demonstrating a promising candidate for displays. In addition, the CsPbBr3/Cs4PbBr6-LP-based WLEDs were also demonstrated in a VLC system. The results suggested the great potential of these high-performance WLEDs as an excitation light source to achieve VLC.

Structural Features and Optical Properties of All-Inorganic Zero-Dimensional Halides Cs4PbBr6–xIx Obtained by Mechanochemistry

“…This fact makes the A 4 PbX 6 phase often referred to as a zero-dimensional (0D) perovskite. − The optical properties of such crystals closely resemble those of individual [PbX 6 ] 4– clusters observed experimentally in halide salts doped with Pb 2+ ions. While the 3D and 2D phases of LHPs are well studied and reported, the 0D perovskites are comparatively less explored, with only very recent works revisiting the optical properties of Cs 4 PbBr 6 nanocrystals. − …”

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

“…Combining TEM and XRD characterization, it is evident that the obtained green crystals are composed of Cs 4 PbBr 6 crystals with embedded CsPbBr 3 nanocrystals, indicating a partial phase transition from Cs 4 PbBr 6 to CsPbBr 3 . 24,34,35 The SEM (Fig. 2f) shows the primary rhombus morphology of Cs 4 PbBr 6 SCs with some surface defects.…”

“…These disadvantages severely hinder the practical applications of perovskite NCs for VLC. 24 In contrast, producing perovskite SCs on a large scale can be achieved using mild and straightforward synthesis methods. Besides simplified synthesis processes with low cost, perovskite SCs offer advantages such as high charge carrier mobility, tunable optoelectronic characteristics, and ease of subsequent processing.…”

High-Performance In3+-Doped CsPbBr3 Quantum Dots for Wide Color Gamut Backlighting

“…Perovskite quantum dots (QDs) have achieved great attention in displays and solar cell in recent years. , In particular, CsPbBr 3 QDs are considered as promising green emitters for LCD backlighting to achieve a wide color gamut due to their narrow emission properties, − but there are still some challenges in their application, such as low stability under prolonged exposure to light or high temperature. − The poor thermal stability of QDs is due to the inability of long-chain ligands to bind tightly to the surface of QDs and detach from the surface of QDs upon heating, and in addition, heating can cause severe aggregation of QDs, both of which will quench their emission. , The poor photostability of QDs is due to the light soaking effect. , When QDs are exposed to continuous light irradiation, the surface atoms detach from the surface and form more vacancy defects, which will reduce their emission. , To improve the stability of CsPbBr 3 QDs, surface coating has been shown to be an effective way . For this strategy, CsPbBr 3 QDs are encapsulated by inorganic materials (e.g., SiO 2 and Al 2 O 3 ) − or polymers (e.g., polyethylenimine) , or MOF, which isolate CsPbBr 3 QDs from each other and from the external environment, inhibit light-induced decomposition and aggregation, and thus improve their stability .…”

“…10,11 The poor photostability of QDs is due to the light soaking effect. 12,13 When QDs are exposed to continuous light irradiation, the surface atoms detach from the surface and form more vacancy defects, which will reduce their emission. 12,13 To improve the stability of CsPbBr 3 QDs, surface coating has been shown to be an effective way.…”