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50 years ago, television screens used bulky cathode ray tubes (CRTs) with a size limited to about 70 cm in diagonal (28 in.), while flat panel displays belonged to the realm of science fiction. Although the performance of CRTs in terms of energy consumption, size, and color rendering slowly improved, there were numerous applications where flat panel displays would present a tremendous advantage, notably for confined spaces and in portable equipment. Starting from the 1970s, AC thin-film electroluminescence (ACTFEL) was investigated as a high performance alternative to the—also emerging—liquid crystal displays (LCDs) and plasma display panels (PDPs). For a number of years, ACTFEL developed from the phase of fundamental research to commercial products (for monochrome displays) and full color prototype displays. However, due to the fast development and strong cost reduction of LCDs, ACTFEL did not remain competitive and most of the research activities were ceased. The current overview sketches a brief history of the ACTFEL technology, its merits and limitations, and the reasons why such displays still have their use in some niche applications. [ABSTRACT FROM AUTHOR]

Mn5+ emission is a promising candidate for imaging deep tissue structures (e.g., vessels, tumors) in the second near‐infrared (NIR‐II, 1000–1350 nm) region. However, its practical application is impeded by the limited quantum efficiency of the available phosphors due to the unstable valence state of Mn5+. Herein, a novel strategy involving site competition is proposed to stabilize the Mn5+ state by the introduction of valence‐unstable Bi2+/3+. The results demonstrate that Bi3+ ions tend to occupy two different Ca2+ ion sites within the Ca6Ba(PO4)4O lattice. The incorporation of a small amount of Bi3+ effectively suppresses the amount of Mn2+ in Ca2+ sites. This is also confirmed by spectroscopic experiments and density function theory calculations. Notably, an ultra‐high internal quantum efficiency of 82.3% is achieved under excitation at 653 nm, surpassing more than twofold the previously reported value of 37.5% in Ca6Ba(PO4)4O: Mn5+. As a proof of concept, deep tissue imaging with a penetration depth of ≈2.8 cm is achieved using a self‐produced NIR‐II light‐emitting diodes device embedded with Ca6Ba(PO4)4O: 0.003Mn5+/0.003Bi3+ powder. These findings provide valuable insights into improving the luminescent properties associated with Mn5+ ions and pave the way for deep tissue imaging with high spatiotemporal resolution. [ABSTRACT FROM AUTHOR]

Passive dosimeters enabling accurate measurement of doses from gamma rays to visible light are necessary to ensure efficient utilization of electromagnetic radiation in numerous fields like medical diagnostics and industrial manufacturing. The specific requirements for dosimeters in terms of dosimetry range, sensitivity, accuracy, and stability for each application have led to the development of various dosimeters based on new materials and new mechanisms. Here, a comprehensive review of different types of dosimeters classified according to the response signal, namely electron paramagnetic resonance, electrical, and optical, is provided. This review starts with a general introduction to dosimetry, a classification of dosimeters, and an elucidation of the necessity of dosimeters in various ranges of the electromagnetic spectrum. This is followed by an overview of the fundamental requirements of dosimeters, an explanation of the general dosimetry procedure, and the dosimetric quantities. Emphasis is given to the working mechanism, the design concept, and applications of each type of dosimeter as well as their respective strengths and drawbacks. Challenges and prospects are presented at the end of the review. This review provides an insightful overview of the material‐mechanism‐characteristics‐application relationship of different types of dosimeters that hopefully can serve as inspiration for the development of new devices. [ABSTRACT FROM AUTHOR]

Persistent luminescence (PersL) materials attract extensive interest in the scientific community nowadays due to their great potential in various fields, such as night‐vision signage, high‐level anticounterfeiting, in vivo bioimaging, and X‐ray extension imaging. However, the majority of PersL materials are synthesized by time‐ and energy‐consuming processes such as high‐temperature solid‐state reactions or hydrothermal synthesis. In this work, a rapid one‐step microwave‐assisted solid state (MASS) synthesis of La2MgGeO6‐based robust double perovskite PersL material is successfully achieved, without any secondary thermal treatment, which limits the total synthesis time to 30 min. Furthermore, this MASS approach is also employed to integrate multimodal luminescence into one single La2MgGeO6 matrix with triple dopants (Mn4+, Yb3+, and Er3+) for light conversion. Impressively, multimodal and multicolor luminescence is obtained with different responsiveness of external stimulations. Notably, the energy transfer among different trapping levels is observed upon photo‐stimulation. This work provides a good example of the feasibility of MASS method to prepare luminescent materials with abundant optical features in an efficient, sustainable, environmentally friendly, and easily manageable way. [ABSTRACT FROM AUTHOR]

Persistent luminescence (PersL) materials show long-lasting emission after irradiation with excitation light. Usually, to obtain PersL, excitation with ultraviolet (UV) or visible light is necessary, which limits the use of this phenomenon when the material is in a non-transparent medium for excitation light. A solution to this problem comes from upconverting nanoparticles (UCNPs), which convert near-infrared light, usually not absorbed by such media as polymers or biological tissues, to higher-energetic UV photons, recharging the PersL phosphors. In this article, we report composite materials consisting of PersL phosphor and UCNPs, i.e. SrAl2O4:Eu2+ or ZnGa2O4:Cr3+ and upconverting LiYbF4:Tm3+@LiYF4 core@shell nanoparticles. These materials show dual-emission properties - bright upconversion from near-infrared (NIR at 975 nm) to ultraviolet (UV at 347 nm) and long-lasting PersL in the visible light range. The obtained composite materials present intense, persistent luminescence after the NIR laser excitation. This article proves efficient energy transfer from UCNPs to PersL phosphor and opens new possibilities in the design and synthesis of composite materials. By employing the high-resolution 3D-printing technology, we experimentally confirmed the possibility of multi-modal optical information storage by applying the synthesized materials, developing multi-dimensional microstructured patterns with QR code, letters and first bi-modal, single- and double-layered 8-bit codes based on the combination of PersL and upconversion emission. [ABSTRACT FROM AUTHOR]

25 years after the first papers on the development of Periodic Mesoporous Organosilicas, and in this special issue in honor of prof. Ozin who stood at the cradle of PMOs, we here report for the first time an "acac-PMO" with the acac-functionality intact and embedded in the organic environment of the linker. Periodic mesoporous organosilicas (PMOs) have emerged as versatile sensors due to their stability, low toxicity, and scalability. This study reports for the first time on embedding the acetylacetone (acac) group into the PMO backbone. This integration of acac into the PMO framework opens new applications in both sensing and catalysis. The Eu3+ grafted acac-PMOs demonstrate enhanced sensitivity, with a detection limit of 108 nM, and high selectivity in aqueous copper (Cu2+) ion sensing. Additionally, these novel PMOs show high catalytic efficiency in Mannich reactions. [ABSTRACT FROM AUTHOR]

This study explores the potential of combining periodic mesoporous organosilicas (PMOs) with a fluorescent dye to develop a ratiometric thermometry system with enhanced stability, sensitivity, and biocompatibility. PMOs, ordered porous materials known for their stability and versatility, serve as an ideal platform. Curcumin, a natural polyphenol and fluorescent dye, is incorporated into PMOs to develop curcumin-functionalized PMOs (C-PMO) and curcumin-pyrazole-functionalized PMOs (CP-PMO) via hydrolysis and co-condensation. These PMOs exhibit temperature-dependent fluorescence properties. The next step involves encapsulating rhodamine B (RhB) dye within the PMO pores to create dual-emitting PMO@dye nanocomposites, followed by a lipid bilayer (LB) coating to enhance biocompatibility and dye retention. Remarkably, within the physiological temperature range, C-PMO@RhB@LB and CP-PMO@RhB@LB demonstrate noteworthy maximum relative sensitivity (Sr) values of up to 1.69 and 2.60% K−1, respectively. This approach offers versatile means to create various ratiometric thermometers by incorporating different fluorescent dyes, holding promise for future temperature sensing applications. [ABSTRACT FROM AUTHOR]

Porous organic polymers (POPs), and especially covalent triazine frameworks (CTFs), are being developed as the next generation of metal‐free heterogeneous photocatalysts. However, many of the current synthetic routes to obtain these photoactive POPs require expensive monomers and rely on precious metal catalysts, thus hindering their widespread implementation. In this work, a range of POPs was synthesized from simple unfunctionalized aromatic building blocks, through Lewis acid‐catalyzed polymerization. The obtained materials were applied, for the first time, as heterogeneous photocatalysts for the aromatization of N‐heterocycles. With the use of the most active material, denoted as CTF‐Pyr, which consists of photoactive pyrene and triazine moieties, a wide range of pyridines, dihydroquinoline‐5‐ones, tetrahydroacridine‐1,8‐diones and pyrazoles were obtained in excellent yields (70–99 %). Moreover, these reactions were carried out under very mild conditions using air and at room temperature, highlighting the potential of these materials as catalysts for green transformations. [ABSTRACT FROM AUTHOR]