Highly sensitive temperature sensors based on the fluorescence intensity ratio of dual-emissive lead-free metal halides.

Given that optical thermometers are widely used due to their unique advantages, this study aims to address critical challenges in existing technologies, such as insufficient sensitivity, limited temperature measurement ranges, and poor signal recognition capabilities. Herein, we develop a thermometer based on the fluorescence intensity ratio (FIR) of Sb-doped CsNaInCl (CsNaInCl:Sb). As the temperature increases from 203 to 323 K, the thermally induced transition from triplet to singlet self-trapped excitons (STEs) leads to enhanced 455 nm photoluminescence (PL) from singlet STE recombination.

Research Progress on Rashba Effect in Two-Dimensional Organic-Inorganic Hybrid Lead Halide Perovskites.

The Rashba effect appears in the semiconductors with an inversion-asymmetric structure and strong spin-orbit coupling, which splits the spin-degenerated band into two sub-bands with opposite spin states. The Rashba effect can not only be used to regulate carrier relaxations, thereby improving the performance of photoelectric devices, but also used to expand the applications of semiconductors in spintronics. In this mini-review, recent research progress on the Rashba effect of two-dimensional (2D) organic-inorganic hybrid perovskites is summarized.

Advanced Optical Information Encryption Enabled by Polychromatic and Stimuli-Responsive Luminescence of Sb-Doped Double Perovskites.

The smart materials with multi-color and stimuli-responsive luminescence are very promising for next generation of optical information encryption and anti-counterfeiting, but these materials are still scarce. Herein, a multi-level information encryption strategy is developed based on the polychromatic emission of Sb-doped double perovskite powders (SDPPs). CsNaInCl:Sb, CsKInCl:Sb, and CsAgInCl:Sb synthesized through coprecipitation methods exhibit broadband emissions with bright blue, cyan, and orange colors, respectively.

Room-Temperature High-Performance Photodetector and Phototransistor Based on PdSe/ZnInS Alloy Heterojunctions.

Various semiconductor devices have been developed based on 2D heterojunction materials owing to their distinctive optoelectronic properties. However, to achieve efficient charge transfer at their interface remains a major challenge. Herein, an alloy heterojunction concept is proposed.

Monolithic 2D Perovskites Enabled Artificial Photonic Synapses for Neuromorphic Vision Sensors.

Neuromorphic visual sensors (NVS) based on photonic synapses hold a significant promise to emulate the human visual system. However, current photonic synapses rely on exquisite engineering of the complex heterogeneous interface to realize learning and memory functions, resulting in high fabrication cost, reduced reliability, high energy consumption and uncompact architecture, severely limiting the up-scaled manufacture, and on-chip integration. Here a photo-memory fundamental based on ion-exciton coupling is innovated to simplify synaptic structure and minimize energy consumption.

Co-multiplexing spectral and temporal dimensions based on luminescent materials.

Optical multiplexing is a pivotal technique for augmenting the capacity of optical data storage (ODS) and increasing the security of anti-counterfeiting. However, due to the dearth of appropriate storage media, optical multiplexing is generally restricted to a single dimension, thus curtailing the encoding capacity. Herein, the co-multiplexing spectral and temporal dimensions are proposed for optical encoding based on photoluminescence (PL) and persistent-luminescence (PersL) at four different wavelengths.

Bioinspired hierarchical colloidal crystal paper with Janus wettability for oil/water separation and heavy metal ion removal.

Increasing attention has been paid recently to superwettability and its prospective potential applications in various fields. A new approach towards the establishment of flexible, self-assembled superhydrophobic surfaces with self-reported wettability on a variety of substrates has been advanced. The approach involves the fabrication of a dense monolayer of photonic crystal films that possess a layered structure with superior adhesion at the liquid-gas-solid interface.

Snapshot multi-frame parallel spectral holographic microscopy based on a reconfigurable optical comb.

We present a snapshot multi-frame parallel holographic microscopy system through a reconfigurable optical comb source, which consists of a digital micromirror device (DMD) based spectrum filter system and a spectroscopic Michelson interferometric system. The proposed system allows arbitrarily tuning comb spacing and comb number, and the capturing of multi-frame images without overlap in one exposure. As a result, high-quality spectral holograms can be obtained with less acquisition time.

Tunable Multicolor Fluorescence of Perovskite-Based Composites for Optical Steganography and Light-Emitting Devices.

Multicolor fluorescence of mixed halide perovskites enormously enables their applications in photonics and optoelectronics. However, it remains an arduous task to obtain multicolor emissions from perovskites containing single halogen to avoid phase segregation. Herein, a fluorescent composite containing Eu-based metal-organic frameworks (MOFs), 0D CsPbBr, and 3D CsPbBr is synthesized.

Structural characterizations on the degradation of 2D organic-inorganic hybrid perovskites and its enlightenment to improved stability.

Despite the demonstrated high-efficiency of solar cells and light-emitting devices based on two-dimensional (2D) perovskites, intrinsic stability of the 2D perovskites is yet far from satisfactory. In this work, we find the 2D (BA)PbIperovskite crystals rapidly degrade in the ambient conditions and the photoluminescence (PL) nearly completely quenches in 6 d. Moreover, the PL shoulder band due to defects and absorption band of PbIgradually rise during degradation, suggesting the precipitation of PbI.

Mechanism of Photoinduced Phase Segregation in Mixed-Halide Perovskite Microplatelets and Its Application in Micropatterning.

Photoinduced phase segregation (PPS) is considered as a dominant factor that greatly deteriorates the performances of mixed-halide perovskite devices. However, the mechanism of PPS is still under fierce debate. Herein, CsPb(Br/Cl) microplatelets (MPs) with homogeneous and heterogeneous surfaces are obtained by controlling the growth conditions.

Interference-free SERS nanoprobes for labeling and imaging of MT1-MMP in breast cancer cells.

The expression of membrane type-1 matrix metalloproteinase (MT1-MMP) in cancer cells is critical for understanding the development, invasion and metastasis of cancers. In this study, we devised an interference-free surface-enhanced Raman scattering (SERS) nanoprobe with high selectivity and specificity for MT1-MMP. The nanoprobe was comprised of silver core-silica shell nanoparticle with a Raman reporter tag (4-mercaptobenzonitrile) embedded in the interface.

Microsteganography on all inorganic perovskite micro-platelets by direct laser writing.

Direct laser writing (DLW) is a mask-free and cost-efficient micro-fabrication technology, which has been explored to pattern structures on perovskites. However, there is still a lack of research on DLW methods for microsteganography. Herein, we developed a sophisticated DLW condition to pattern on CsPbBr perovskite micro-platelets (MPs).

Power-Free and Self-Cleaning Solar Light Detector Based on the Temperature-Sensitive Structural Color and Photothermal Effect.

In this work, photothermal materials are integrated with a temperature-sensitive hydrogel and structural color for visually detecting solar intensity. Inspired by the functional performance of beetles, the photothermal layer is constructed by depositing candle soot on a film of Cu nanoparticles, while the temperature-sensitive colored hydrogel is fabricated by self-assembling colloidal photonic crystals on poly(-isopropylacrylamide) (PNiPAM). The deposition of candle soot not only improves the photothermal performance but also leads to a superhydrophobic surface with a self-cleaning function.

Fluorescent dynamics of CsPbBr nanocrystals in polar solvents: a potential sensor for polarity.

During synthesis, device processes, and applications of perovskite nanocrystals (NCs), there are usually inevitable interactions between perovskite NCs and polar solvents. To elaborately control the properties of perovskite NCs, investigating the effects of solvent polarity on perovskite NCs is thus highly important. Herein, fluorescent variations induced by different solvents into CsPbBr NCs solution are systematically studied.

Reusable Self-Sterilization Masks Based on Electrothermal Graphene Filters.

Surgical mask is recommended by the World Health Organization for personal protection against disease transmission. However, most of the surgical masks on the market are disposable that cannot be self-sterilized for reuse. Thus, when confronting the global public health crisis, a severe shortage of mask resource is inevitable.

Bioinspired Free-Standing One-Dimensional Photonic Crystals with Janus Wettability for Water Quality Monitoring.

Materials with specific wettability properties have aroused enormous interest and research for their broad application prospects in chemical reaction, medical diagnosis, biological analysis, etc. Here, inspired by the unique Janus wettability of lotus leaf and Bragg stacks of beetles, we present a free-standing film with Janus wettability and tunable structural color for water quality monitoring. This film is constructed by using a flexible polymer polyurethane (PU) to pack poly(-isopropyl acrylamide-bis-acrylamide-acrylic acid) (P(NiPAAm-bis-AA))/TiO one-dimensional photonic crystals (1DPCs) into a free-standing state with Janus wettability and tunable structural color.

Porous reduced graphene oxide/nickel foam for highly efficient solar steam generation.

Solar-driven water evaporation is considered to be an effective method for seawater desalination and wastewater purification. Here, we report a novel solar steam generation (SSG) system based on reduced graphene oxide (rGO)/nickel foam. Porous rGO foam acting as a photothermal conversion layer is fabricated by coating the rGO microsheets on the metallic nickel foam.

A Graphene-Coated Mo Tip Array for Highly-Efficient Nanostructured Electron Field Emitters.

An efficient electron field emitter based on a monolayer graphene coated well aligned Mo tip array has been designed, fabricated, and evaluated. The advantages of this hybrid nanostructure film morphology are explored and discussed. Efficient and stable field emissions with low turn-on fields have been observed with the new devices.

Copper nanoparticles with near-unity, omnidirectional, and broadband optical absorption for highly efficient solar steam generation.

Solar steam generation provides a renewable and environmentally friendly approach to solve the water shortage issue. The pursuit of efficient, stable, and cheap photothermal agents is thus of great significance. In this work, Cu nanoparticles (NPs) fabricated simply by a substitution reaction, exhibit a near-unity (∼97.

ZnO electron field emitters on three-dimensional patterned carbon nanotube framework.

A three-dimensional patterned CNT framework was prepared in a thermal chemical vapor deposition system. ZnO nanoneedles with different areal density were subsequently grown on it via hydrothermal method. By combining the advantages of high aspect ratio, more effective emission sites with minimized screen effect and good Ohmic contact between ZnO nanoneedles and CNT framework, the ZnO/CNT hierarchical nanostructures with medium areal density exhibit a favorable FE performance which makes it promising candidate for cold cathode nanomaterials.

Application of field emission as backlight unit for liquid crystal displays.

The paper first analyzes the effect of backlight unit for liquid crystal displays on the respect of image quality and power consumption. A spatially and temporally addressable backlight is required in the future liquid crystal displays which have lower power consumption and higher image quality. Compared to the currently used light emitting diode backlight, the simulation results indicate that a rectangular-shaped backlight has better performances on the respect of reducing power consumption and improving image quality.