Surface-enhanced Raman scattering of R6G dimerization during self-healing of gel.

Traditional surface-enhanced Raman scattering (SERS) substrates seeking uniformity and reproducibility of the Raman signal often assume and require that hot spots remain consistently stable during Raman testing. Recently, the non-uniform accumulation in SERS sample pre-concentration strategies have inspired the direct use of self-healing noble metal aerogels (NMAs), as the sample pretreatment presented in this work, and uncovered more diverse Raman information of substances during the dynamic process of laser irradiation. Rare characteristic peaks such as 820 cm⁻ for R6G within a specific concentration range were observed, and potential processes including R6G dimerization and desorption were analyzed.

Metal oxide hybridization enhances room temperature phosphorescence of carbon dots-SiO matrix for information encryption and anti-counterfeiting.

Room temperature phosphorescent (RTP) carbon dot (CD) materials have been widely used in various fields, but it is difficult to achieve a long lifetime, high stability and easy synthesis. In particular, realizing the phosphorescence emission of CDs using a metal oxide (MO) matrix is a challenge. Here, solid gels are synthesized hydrolysis, and then RTP CDs are synthesized based on a SiO matrix (CDs@SiO) and hybridized with a MO matrix (CDs@SiO-MO) by high-temperature calcination.

One-Step Preparation of High-Stability CsPbX/CsPbX Composite Microplates with Tunable Emission.

The core-shell structure is an effective means to improve the stability and optoelectronic properties of cesium lead halide (CsPbX (X = Cl, Br, I)) perovskite quantum dots (QDs). However, confined by the ionic radius differences, developing a core-shell packaging strategy suitable for the entire CsPbX system remains a challenge. In this study, we introduce an optimized hot-injection method for the epitaxial growth of the CsPbX substrate on CsPbX surfaces, achieved by precisely controlling the reaction time and the ratio of lead halide precursors.

Stability Enhancement in All-Inorganic Perovskite Light Emitting Diodes via Dual Encapsulation.

Addressing the challenge of lighting stability in perovskite white light emitting diodes (WLEDs) is crucial for their commercial viability. CsPbX (X = Cl, Br, I, or mixed) nanocrystals (NCs) are promising for next-generation lighting due to their superior optical and electronic properties. However, the inherent soft material structure of CsPbX NCs is particularly susceptible to the elevated temperatures associated with prolonged WLED operation.

Ultrastable CsPbBr@CsPbBr@TiO Composites for Photocatalytic and White Light-Emitting Diodes.

Although cesium halide lead (CsPbX, X = Cl, Br, I) perovskite quantum dots (QDs) have excellent photovoltaic properties, their unstable characteristics are major limitations to application. Previous research has demonstrated that the core-shell structure can significantly improve the stability of CsPbX QDs and form heterojunctions at interfaces, enabling multifunctionalization of perovskite materials. In this article, we propose a convenient method to construct core-shell-structured perovskite materials, in which CsPbBr@CsPbBr core-shell micrometer crystals can be prepared by controlling the ratio of Cs/Pb in the precursor and the reaction time.

Studies on the optical stability of CsPbBr with different dimensions (0D, 1D, 2D, 3D) under thermal environments.

The thermal stability of phosphor materials had long been a bottleneck in their commercialization. Nowadays, cesium lead halide perovskite CsPbBr has been considered a potential replacement for the next generation of optoelectronic devices due to its excellent optical and electronic properties, however, the devices inevitably generate high temperatures on the surface under prolonged energization conditions in practical applications, which can be fatal to CsPbBr. Despite the various strategies that have been employed to improve the thermal stability of CsPbBr, systematic studies of the thermal stability of the basis CsPbBr are lacking.

Preparation of CsPb(Cl/Br)/TiO:Eu composites for white light emitting diodes.

The inherent single narrow emission peak and fast anion exchange process of cesium lead halide perovskite CsPbX (X = Cl, Br, I) nanocrystals severely limited its application in white light-emitting diodes. Previous studies have shown that composite structures can passivate surface defects of NCs and improve the stability of perovskite materials, but complex post-treatment processes commonly lead to dissolution of NCs. In this study, CsPb(Cl/Br) NCs was in-situ grown in TiO hollow shells doped with Eu ions by a modified thermal injection method to prepare CsPb(Cl/Br)/TiO:Eu composites with direct excitation of white light without additional treatment.

In Situ Fabrication of Lead-Free Double Perovskite/Polymer Composite Films for Optoelectronic Devices and Anticounterfeit Printing.

Lead-free double perovskites (DP) have the potential to become a rising star in the next generation of lighting markets by addressing the toxicity and instability issues associated with traditional lead-based perovskites. However, high concentrations of hydrochloric acid (HCl) were often employed as a solvent in the preparation of most DPs, accompanied by slow crystallization at high temperatures, which not only raised the risk and cost in the preparation process, but also had a potential threat to the environment. Here, an in situ fabrication strategy was proposed to realize the crystallization of DP in the polymer at low temperature with a mild dimethyl sulfoxide (DMSO) solvent, and subsequently obtained optically well-behaved CsNaAgBiCl/PMMA composite films (CFs) by doping with Ag, generating bright orange luminescence with a photoluminescence quantum yield (PLQY) of up to 21.

Optical Properties and Upconversion Luminescence of BaTiO Xerogel Structures Doped with Erbium and Ytterbium.

Erbium upconversion (UC) photoluminescence (PL) from sol-gel derived barium titanate (BaTiO:Er) xerogel structures fabricated on silicon, glass or fused silica substrates has been studied. Under continuous-wave excitation at 980 nm and nanosecond pulsed excitation at 980 and 1540 nm, the fabricated structures demonstrate room temperature PL with several bands at 410, 523, 546, 658, 800 and 830 nm, corresponding to the H → I, H → I, S → I, F→ I and I→ I transitions of Er ions. The intensity of erbium UC PL increases when an additional macroporous layer of strontium titanate is used beneath the BaTiO xerogel layer.

Trioctylphosphine-Assisted Pre-protection Low-Temperature Solvothermal Synthesis of Highly Stable CsPbBr/TiO Nanocomposites.

Lead halide perovskite quantum dots (PQDs) are reported as a promising branch of perovskites, which have recently emerged as a field in luminescent materials research. However, before the practical applications of PQDs can be realized, the problem of poor stability has not yet been solved. Herein, we propose a trioctylphosphine (TOP)-assisted pre-protection low-temperature solvothermal synthesis of highly stable CsPbBr/TiO nanocomposites.

A versatile approach for shape-controlled synthesis of ultrathin perovskite nanostructures.

Very recently, ultrathin perovskite nanostructures, with the advantages of perovskite and ultrathin properties, have received an enormous level of interest due to their many fascinating properties, such as a strong quantum confinement effect and a large specific surface area. In spite of this incredible success of perovskite nanocrystals (NCs), the development of perovskite NCs is still in its infancy, and the production of high-quality ultrathin perovskite nanostructures has been a hot topic in the fields of nanoscience and nanotechnology. Herein, we demonstrate that ultrathin CsPbBr3 perovskite nanosheets (NSs) can be obtained by a simple mixing of precursor-ligand complexes under ambient conditions.

Structural Dependent Eu Luminescence, Photoelectric and Hysteresis Effects in Porous Strontium Titanate.

Eu doped porous nanostructured SrTiO films and powder fabricated by sol-gel route without using any precursor template are characterized by different morphology and phase composition. The films show red and yellow luminescence with the most intensive photoluminescence (PL) bands at 612 nm and 588 nm, respectively. Raman, secondary ion mass spectrometry (SIMS), and X-ray diffraction (XRD) analysis of undoped nanostructured porous SrTiO films showed the presence of TiO, SrO, and SrTiO phases and their components.

Pressure-Driven Transformation of CsPbBrI Nanoparticles into Stable Nanosheets in Solution through Self-Assembly.

Very recently, two-dimensional (2D) perovskite nanosheets (PNSs), taking the advantages of perovskite as well as the 2D structure properties, have received an enormous level of interest throughout the scientific community. In spite of this incredible success in perovskite nanocrystals (NCs), self-assembly of many nanostructures in metal halide perovskites has not yet been realized, and producing highly efficient red-emitting PNSs remains challenging. In this Letter, we show that by using CsPbBrI perovskite nanoparticles (NPs) as a building block, PNSs can emerge spontaneously under high ambient pressure via template-free self-assembly without additional complicated operation.

Highly stable Na: CsPb(Br,I)@AlO nanocomposites prepared by a pre-protection strategy.

Among the leading energy materials, metal tri-halide perovskite quantum dots (PQDs) with outstanding optoelectronic properties are at the forefront of current research. However, enormous challenges remain to be addressed, including hazardous components and poor stability, before achieving practical applications of PQDs. Although there are diverse methods to improve the stability of PQDs, it is of central importance to avoid damage during operation.

Reversible transformation between CsPbBr nanowires and nanoparticles.

We show that CsPbBr nanowires (NWs) are formed by the hierarchical arrangement of individual nanoparticles (NPs), and reversible transformation from NWs to NPs is also achieved by anion exchange.