The emergent two-dimensional (2D) material, tin diselenide (SnSe₂), has garnered significant consideration for its potential in image capturing systems, optical communication, and optoelectronic memory. Nevertheless, SnSe₂-based photodetection faces obstacles, including slow response speed and low normalized detectivity. In this work, photodetectors based on SnS/SnSe₂ and SnSe/SnSe₂ p?n heterostructures have been implemented through a polydimethylsiloxane (PDMS)?assisted transfer method. These photodetectors demonstrate broad-spectrum photoresponse within the 405 to 850 nm wavelength range. The photodetector based on the SnS/SnSe₂ heterostructure exhibits a significant responsivity of 4.99 × 10³ A?W^?1, normalized detectivity of 5.80 × 10¹² cm?Hz^1/2?W^?1, and fast response time of 3.13 ms, respectively, owing to the built-in electric field. Meanwhile, the highest values of responsivity, normalized detectivity, and response time for the photodetector based on the SnSe/SnSe₂ heterostructure are 5.91 × 10³ A?W^?1, 7.03 × 10¹² cm?Hz^1/2?W^?1, and 4.74 ms, respectively. And their photodetection performances transcend those of photodetectors based on individual SnSe₂, SnS, SnSe, and other commonly used 2D materials. Our work has demonstrated an effective strategy to improve the performance of SnSe₂-based photodetectors and paves the way for their future commercialization.

High-resolution multi-color printing relies upon pixelated optical nanostructures, which is crucial to promote color display by producing nonbleaching colors, yet requires simplicity in fabrication and dynamic switching. Antimony trisulfide (Sb₂S₃) is a newly rising chalcogenide material that possesses prompt and significant transition of its optical characteristics in the visible region between amorphous and crystalline phases, which holds the key to color-varying devices. Herein, we proposed a dynamically switchable color printing method using Sb₂S₃-based stepwise pixelated Fabry-Pérot (FP) cavities with various cavity lengths. The device was fabricated by employing a direct laser patterning that is a less time-consuming, more approachable, and low-cost technique. As switching the state of Sb₂S₃ between amorphous and crystalline, the multi-color of stepwise pixelated FP cavities can be actively changed. The color variation is due to the profound change in the refractive index of Sb₂S₃ over the visible spectrum during its phase transition. Moreover, we directly fabricated sub-50 nm nano-grating on ultrathin Sb₂S₃ laminate via microsphere 800-nm femtosecond laser irradiation in far field. The minimum feature size can be further decreased down to ~45 nm (λ/17) by varying the thickness of Sb₂S₃ film. Ultrafast switchable Sb₂S₃ photonic devices can take one step toward the next generation of inkless erasable papers or displays and enable information encryption, camouflaging surfaces, anticounterfeiting, etc. Importantly, our work explores the prospects of rapid and rewritable fabrication of periodic structures with nano-scale resolution and can serve as a guideline for further development of chalcogenide-based photonics components.

采用高温固相法制备了一种具有颜色变化的长余辉发光材料Mg₃Y₂Ge₃O₁₂∶Pr³⁺。通过X射线衍射、激发发射光谱、余辉衰减及热释光曲线等，对样品的结构、发光及余辉性能进行了系统分析。在283 nm激发下，发射光谱在485 nm和609 nm处表现出两个较强的尖峰发射，分别归属于Pr³⁺离子的³P₂→³H₄及³P₀→³H₆能级跃迁。通过对Pr³⁺离子浓度的调控，有效改变了绿光和红光的相对发射强度，从而实现了发光颜色的多色化。此外，在激发光源停止后该材料同样具有多色的余辉发射，对于最佳样品（Mg₃Y₂Ge₃O₁₂∶0.015Pr³⁺）的余辉时间可达1 200 s以上。之后，我们通过热释光曲线具体研究了陷阱的分布及余辉的充放能过程。结果表明，Mg₃Y₂Ge₃O₁₂∶0.015Pr³⁺材料中浅陷阱的浓度相对较低从而导致室温下的余辉性能较弱。由于材料在高温区域具有超宽带陷阱分布，因此，我们进一步探究了其在高温下的多色长余辉性能。在本工作中，我们成功制备了一种单一离子激活的发光及余辉颜色可调的长余辉发光材料，考虑到其在室温以及高温条件下都具有发光及余辉颜色变化的特点，该材料在高温预警标识以及防伪领域有着潜在的应用价值。

自从尺寸依赖的上转换荧光热增强现象在稀土激活的纳米荧光材料中被发现以来，开发具有显著荧光热增强效应的稀土荧光材料俨然成为了一个研究热点。近期的探索发现荧光热增强效应在非纳米尺度稀土荧光材料体系以及非上转换发光过程中均可实现，这进一步拓展了这一有趣光学现象的应用场景。本文总结和归纳了稀土激活荧光热增强材料的最新研究进展，概述了所提出的几类机理以及稀土荧光热增强材料的潜在应用场景，并展望了该类材料的研究发展方向。