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Ce3+-doped lithium alumino-silicate (Li-Al-Si) scintillating glass was prepared using a melting method and crystallized via heat treatment. X-ray diffraction and transmission electron microscopy confirmed the presence of nanocrystals in the materials. Radioluminescence spectra, obtained by X-ray excitation, and luminescence spectra, obtained by 338 nm excitation, showed that the luminescence intensity increased after crystallization. The glass was combined with pure silica as the inner cladding to fabricate a hybrid fiber core using a melt-in-tube technique. The composition of the fiber core was examined using an electron probe microanalyzer. The glass fiber produced strong blue luminescence under UV excitation. After a micro-crystallizing heat treatment of the hybrid fiber at 850 °C in a reducing atmosphere, a Ce3+-doped lithium alumino-silicate glass–ceramic scintillating hybrid fiber was obtained. The nanocrystal structure of the fiber core was examined using micro-Raman spectroscopy. Excitation and luminescence spectra of the hybrid fiber before and after micro-crystallization were measured using microspectrofluorimetry. The results demonstrated that the fiber remained luminous after micro-crystallization. Hence, this work provides a new way to prepare scintillating glass–ceramic hybrid fibers for neutron detection. [ABSTRACT FROM AUTHOR]

Triphenylamine derivatives with narrowband emission have attracted growing attention in purely organic thermally-activated fluorescence (TADF) materials owing to their enhanced color purity and flexible molecular design strategy. Combined time-dependent density functional theory (TD-DFT) and ONIOM (QM/MM) calculations indicate that the excellent planarity of the experimentally developed DQAO could result in gradually decreased intermolecular interactions in the aggregated state at ambient pressure and upon compression, which is unfavorable for suppressing structural relaxation and achieving narrowband emission in its non-doped practical application. Therefore, three structure-modified derivatives, DQAO-Cb, DQAO-Ph, and DQAO-PhCb, were theoretically designed by introducing the spherical o-carborane and dangling phenyl units positioned para to the N atom of the DQAO to provide additional geometrical distortion and steric hindrance. The explorations on the reported DQAO, OQAO, and SQAO found that small structural relaxations, suppressed low-frequency vibrations, and noticeable short-range charge-transfer (SR-CT) natures of DQAO and OQAO are responsible for their much narrower emission spectral full-width at half-maxima (FWHMs) compared to that of SQAO. Introducing the o-carborane unit directly at the para position of the N atom could result in additional scissoring and stretching vibrations of the corresponding DQAO-Cb while the presence of the phenyl unit in DQAO-Ph is beneficial for suppressing the high-frequency vibrations of the pristine DQAO. More importantly, the bridged phenyl unit incorporated in DQAO-PhCb is of particular importance to inhibit the undesired low-frequency scissoring and high-frequency stretching vibrations of the o-carborane unit, which is crucial to reduce the reorganization energy of DQAO-PhCb and achieve narrowband emission. Also, the phenyl unit in DQAO-Ph and DQAO-PhCb helps to shorten charge transfer distances and improve ISC and RISC processes. Since the o-carborane unit is an adopted building block to achieve piezochromic behaviors, the theoretically structure-modified DQAO-PhCb is expected to exhibit narrowband emission, TADF, and piezochromic features all together. Our findings will hopefully provide ideas for designing triphenylamine-based TADF emitters with narrowband emission and piezochromic behaviors. [ABSTRACT FROM AUTHOR]

The striking change in the emission color/intensity of piezochromic luminescent materials in response to external mechanical stimuli (e.g., pressure, grinding, and stretching) has attracted attention due to potential applications in optical data storage devices, pressure sensors, and optoelectronic devices. The majority of organic materials show redshifted and quenched emission with increasing pressure. Herein, covalently linked donor/acceptor (D/A) o‐carborane dyads that exhibit dual luminescence peaks due to the occurrence of photoinduced electron transfer (PET) are reported. Interestingly, an anomalous phenomenon of pressure‐induced blueshifted and enhanced luminescence is clearly observed. From 1 atm to 1.09 GPa, the restriction of intramolecular motion increases the luminescence of o‐carborane dyads. At high pressures, the compressed o‐carborane unit suppresses PET and decreases the energy gap between the upper excited states. Since the rate of the internal conversion (IC) process is higher than that of PET, the charge transfer (CT) emission gradually disappears, causing the o‐carborane dyads to exhibit blueshifted luminescence. Therefore, a novel strategy for achieving the pressure‐induced enhanced and blueshifted luminescence characteristics of organic materials is reported in this work. [ABSTRACT FROM AUTHOR]

Organic–inorganic manganese halide with environmentally friendly properties has become a new candidate material for backlight display applications. In this article, tetraethylammonium bromide (C8H20N)2MnBr4 is synthesized by a simple room temperature evaporation method. The tetrahedral coordinated Mn2+ demonstrates a green emission peak at 523 nm and a commendable photoluminescence quantum yield (PLQY) of 81.7%. To improve its stability, different proportions of Zn2+ are incorporated, leading to the discovery of (C8H20N)2Mn0.95Zn0.05Br4 as the most stable variant with a high PLQY of 84.3%. Additionally, by utilizing a sandwich method and double‐layer polyethylene terephthalate (PET) film encapsulation, the powder‐to‐binder ratio and thickness gradient are optimized, resulting in the ideal (C8H20N)2Mn0.95Zn0.05Br4@PET film with a powder‐to‐binder ratio of 1:2 and a thickness of 0.5 mm. Remarkably, the film exhibits superior stability against water, heat, and photo degradation. Finally, the light conversion film prepared from (C8H20N)2Mn0.95Zn0.05Br4@K2SiF6: Mn4+@PET composite material is applied to backlight display, and the color gamut covers 112% of NTSC 1953 and 83% of Rec. 2020. This study provides a feasible route for developing environmentally friendly, low‐cost, and high‐performance liquid crystal displays. [ABSTRACT FROM AUTHOR]

Recently, two-dimensional (2D) layered polarized ZnIn2S4 nanosheets have been successfully synthesized in experiments. However, the polarized monolayers are unstable in air, which hinders their practical applications. Therefore, in this work, we proposed a new family of nonpolarized monolayers (β2-phase) ZnX2Z4 (X = In, Al, and Ga; Z = S, Se, and Te) by first-principles. It is confirmed that the energies of β2-phase ZnX2Z4 are lower than those of the polarized and β-phase ZnX2Z4 monolayers. Moreover, these ZnX2Z4 monolayers have not only desirable indirect band gaps but also high electron mobility (up to 103 cm2 V−1 s−1), revealing a fascinating visible light absorption range. Furthermore, β2-phase ZnX2Te4 (X = In, Al, and Ga) has ultra-low lattice thermal conductivity and high ZT value (up to 0.89), suggesting that these monolayers can be good candidates for thermoelectric materials. These new 2D ternary monolayers not only effectively broaden the family of 2D materials but also provide promising candidates for optoelectronic and thermoelectric materials. [ABSTRACT FROM AUTHOR]