Pressure‐assisted cooling to grow ultra‐stable Cs₃Cu₂l₅ and CsCu₂l₃ single crystals for solid‐state lighting and visible light communication

Abstract

Owing to the excellent optical properties, white light‐emitting diodes (WLEDs) based on metal halide perovskites have attracted great attention as promising light source for solid‐state lighting and wireless visible light communication (VLC). However, the instability and toxicity of classic hybrid lead halides hinder their practical applications. Here, a pressure‐assisted cooling method is developed to grow lead‐free Cs3Cu2I5 and CsCu2I3 single crystals, which exhibit more excellent stability, larger size and uniform orientations in comparison with pressure‐free cooling method. Then, both single crystals are used as the emitters of WLEDs without encapsulation, exhibiting a high Color Rendering Index of 91, a decent Commission Internationale de l'Eclairage coordinate of (0.33, 0.33), a proper Correlated Color Temperature of 5436 K, as well as an excellent 1350‐h operating stability at atmosphere. Furthermore, the prepared WLEDs are utilized in wireless VLC, which possesses a −3 dB bandwidth of 10.1 MHz.

Flexible perovskite scintillators and detectors for X-ray detection

“…Single crystals with less grain boundaries, show advantages of improved carrier mobility, lower bulk defect state density, and more adequate light absorption. 48 Main techniques that were reported capable of synthesizing high performance single crystals include high-temperature Bridgeman ( Figure 5 A), heating precursor solution crystallization (inverse temperature crystallization, Figure 5 B), cooling precursor solution crystallization ( Figure 5 C), hot process ( Figure 5 D), 49 , 50 , 51 , 52 solvent volatilization, anti-solvent-assisted crystallization, vapor phase epitaxial growth, space-limited crystallization, cavitation triggered asymmetrical crystallization methods. For example, Chung et al.…”

“…dissolved the precursor at 100 °C and then lowered the temperature of the saturated precursor to room temperature at a rate of 1 °C h -1 to obtain cesium-copper-iodine single crystals with a centimeter scale. 51 However, the above-mentioned methods generally result in single crystals with a large size/thickness, limiting their applications in flexible X-ray detections. To solve such an issue, Zhang et al.…”

“… (C) A typical cooling precursor solution method. Adapted with permission from Wang et al 51 Copyright 2022, Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. (D) A typical hot-pressing method.…”

Tenability and improvement of the structural, electronic, and optical properties of lead-free CsSnCl3perovskite by incorporating reduced graphene oxide (rGO) for optoelectronic applications

“…20 Also, Baiqian Wang et al developed a pressure-assisted cooling method to synthesize similar perovskites, which exhibit excellent stability for WLED and wireless visible light communication applications. 21 Qionghua Mo et al reported a newly developed air-stable hybrid lead-free halide like [Na (DMSO) 2 ] 3 SbBr 6 , which exhibits high photoluminescence quantum yield and long-term PL decay of 3.1 μs, and such a material is useful for next-generation solid-state illuminations and optoelectronic applications. 22 Furthermore, they improve the photoluminescence quantum yield and stability by incorporating Cl and varying the concentration of Sb in the same perovskites; thus, such work gives an insight into the development of Sb-based organic–inorganic metal halides for solid-state illumination and X-ray imaging.…”

Synthesis of Thermally Stable and Highly Luminescent Cs5Cu3Cl6I2 Nanocrystals with Nonlinear Optical Response

“…[33] In addition, Cs 3 Cu 2 I 5 displayed a broad emission band with a large Stokes shift, which are characteristics of STEs that are primarily seen in Cu(I)-based fluorescence. Following the initial Cs 3 Cu 2 I 5 study, analogs such as CsCu 2 X 3 and Cs 3 Cu 2 X 5 (X = Cl, Br, I) were synthesized, both in the bulk and as nanocrystals (NCs), [34][35][36][37][38][39][40][41][42] and in-depth analyses of their photophysical properties [43] -as well as studies on various applications, from scintillators to light-emitting diodes [44][45][46] were also carried out.…”