Materials with ultralong phosphorescence have wide-ranging application prospects in biological imaging, light-emitting devices, and anti-counterfeiting. Usually, molecular phosphorescence is significantly quenched with increasing temperature, rendering it difficult to achieve high-efficiency and ultralong room temperature phosphorescence. Herein, we spearhead this challenging effort to design thermal-quenching resistant phosphorescent materials based on an effective intermediate energy buffer and energy transfer route. Co-crystallized assembly of zero-dimensional metal halide organic-inorganic hybrids enables ultralong room temperature phosphorescence of (Ph4P)2Cd2Br6 that maintains luminescent stability across a wide temperature range from 100 to 320 K (ΔT = 220 °C) with the room temperature phosphorescence quantum yield of 62.79% and lifetime of 37.85 ms, which exceeds those of other state-of-the-art systems. Therefore, this work not only describes a design for thermal-quenching-resistant luminescent materials with high efficiency, but also demonstrates an effective way to obtain intelligent systems with long-lasting room temperature phosphorescence for optical storage and logic compilation applications. Molecular luminescence is generally significantly quenched at high temperature. Here the authors report a zero-dimensional metal halide hybrid that exhibits zero-thermal-quenching ultralong phosphorescence over a wide temperature range of 220 K, and demonstrate use for Morse code encryption and logic gates.

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Wide range zero-thermal-quenching ultralong phosphorescence from zero-dimensional metal halide hybrids.

All-inorganic perovskite quantum dots (QDs) CsPbX3 (X = Cl, Br, and I) have recently emerged as a new promising class of X-ray scintillators. However, the instability of perovskite QDs and the strong optical scattering of the thick opaque QD scintillator film imped it to realize high-quality and robust X-ray image. Herein, the europium (Eu) doped CsPbBr3 QDs are in situ grown inside transparent amorphous matrix to form glass-ceramic (GC) scintillator with glass phase serving as both matrix and encapsulation for the perovskite QD scintillators. The small amount of Eu dopant optimizes the crystallization of CsPbBr3 QDs and makes their distribution more uniform in the glass matrix, which can significantly reduce the light scattering and also enhance the photoluminescence emission of CsPbBr3 QDs. As a result, a remarkably high spatial resolution of 15.0 lp mm-1 is realized thanks to the reduced light scattering, which is so far a record resolution for perovskite scintillator based X-ray imaging, and the scintillation stability is also significantly improved compared to the bare perovskite QD scintillators. Those results provide an effective platform particularly for the emerging perovskite nanocrystal scintillators to reduce light scattering and improve radiation hardness.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/advs.202003728

Highly Resolved and Robust Dynamic X-Ray Imaging Using Perovskite Glass-Ceramic Scintillator with Reduced Light Scattering.

Crystallization of concentrated colloidal suspensions was studied in real space with laser scanning confocal microscopy. Direct imaging in three dimensions allowed identification and observation of both nucleation and growth of crystalline regions, providing an experimental measure of properties of the nucleating crystallites. By following their evolution, we identified critical nuclei, determined nucleation rates, and measured the average surface tension of the crystal-liquid interface. The structure of the nuclei was the same as the bulk solid phase, random hexagonal close-packed, and their average shape was rather nonspherical, with rough rather than faceted surfaces.

Real Space Imaging of Nucleation and Growth in Colloidal Crystallization

CsPbX3(Cl, Br, I) perovskite quantum dot glass has been widely reported, and the discovery of next-generation perovskite luminescent materials has been challenged by doping rare earth activators with energy-level transitions. In this work, we report a novel Eu-doped quantum dot glass material with tunable luminescence properties. The structure characteristics and tunable luminescence mechanism were investigated by combining X-ray diffraction, X-ray photoelectric spectroscopy, excitation and emission spectra. It was found that Eu ions replaced the lattice of Pb in CsPbBr3 quantum dots and formed CsEuBr3 quantum dots, which resulted in a blue emission. Meanwhile, a green emission from CsPbBr3 quantum dots and a red emission originally from Eu3+ in the glass matrix can also be observed by controlling the heat treatment temperature. A light-emitting diode is designed based on the prepared Eu-doped quantum dot glass without doping any phosphors, and a warm light with CCT at 4075 K is obtained. The present work provides a new luminescence tunable design principle for europium-doped quantum dot glass materials and could inspire the future exploration of rare earth ion-doped quantum dot glass materials.

Nanocrystalline structure control and tunable luminescence mechanism of Eu-doped CsPbBr3 quantum dot glass for WLEDs.

Size-controlled emission of long-time durable CsPbBr3 perovskite quantum dots embedded tellurite glass nanocomposites

Theoretically, the realization of phase transformation in glass requires enough energy to overcome a certain barrier. Conventionally, the transition from amorphous to crystalline phase is realized by controlling the crystallization process in the heating process. However, little progress has been made in the study of mechanical crystallization and hydration crystallization, which do not involve excessive energy transition processes. In this work, CsPbBr3 quantum dot glasses with good thermal stability and water stability were firstly obtained by mechanical crystallization and hydration crystallization methods, which are completely different from the traditional methods. An intense 523 nm emission with a long lifetime of 75.2 ns was observed in the CsPbBr3 quantum dot glass prepared under mechanical stress. Interestingly, a strong green emission was found in the CsPbBr3 quantum dot glass prepared under hydration conditions. Furthermore, the CsPbBr3 quantum dot glass obtained by mechanical devitrification shows the phenomenon of luminescence enhancement with the extension of the observation time in water, which further verifies the phenomenon of the hydration crystallization. In short, the present work not only provides a novel channel for the future study of quantum dots but also brings a significant revolution to the production of quantum dot glass materials.

Luminescence enhancement of CsPbBr3 quantum dot glasses induced by two unexpected methods: mechanical and hydration crystallization

A new whole family perovskites quantum dots (CsPbX3, X=Cl, Br, I) phosphate glasses with full spectral emissions

So far, the application of inorganic glass materials in the field of photocatalysis has not been explored. First, phase separation induced CsPbBr3 quantum dot glasses, as an unprecedented method, i...

Panpan Li

Papers

Nanocrystalline structure control and tunable luminescence mechanism of Eu-doped CsPbBr3 quantum dot glass for WLEDs.

Luminescence enhancement of CsPbBr3 quantum dot glasses induced by two unexpected methods: mechanical and hydration crystallization

A new whole family perovskites quantum dots (CsPbX3, X=Cl, Br, I) phosphate glasses with full spectral emissions

Potential Application of Perovskite Glass Material in Photocatalysis Field

Tunable white light in trivalent europium single doped tin fluorophosphates ultra-low melting glass