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Photoluminescence features of new Eu <sup>3+</sup> -doped Gd <sub/>4</sub> Mo <sub/>7</sub> O <sub/>27</sub> phosphors synthesized using glass crystallization technique
摘要： New Eu3+-doped Gd4Mo7O27 crystals (the molar ratio of Gd2O3/MoO3 = 1/3.5) with a monoclinic structure C2/c (an inversion symmetry) were synthesized through the crystallization of xEu2O3-(18.89-x)Gd2O3-66.11MoO3-15B2O3-1Al2O3 glasses (x = 0.0472 and 1.889) and photoluminescence (PL) emissions of Eu3+ ions were measured for the first time. The crystallized glass with no Eu2O3 addition (x = 0) showed a blue color under the irradiation of ultra-violet light with a wavelength of λ = 254 nm, the emitting color of the crystallized glass with x = 0.0472 was pink, and that of the crystallized glass with x = 1.889 was orange. The charge transfer (CT) of O2-→Mo6+ providing broad peaks centered at around 325 nm was observed in the crystallized glasses. The peak intensity at 591 nm for the 5D0→7F1 transition of Eu3+ ions in the crystallized glasses with x = 0.0472 and 1.889 was very close to that at 615 nm for the 5D0→7F2 transition for the excitation of λex = 394.5 nm. We propose potential of Gd4Mo7O27 as a new host crystal for rare-earth-doped phosphors.
关键词： Eu3+-doping,Glass crystallization,Photoluminescence,Phosphor,Gd4Mo7O27
更新于2025-09-04 15:30:14
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Mobility Enhancement in Polycrystalline Silicon Thin Film Transistors due to the Dehydrogenation Mechanism
摘要： We investigated the mechanism of mobility enhancement after the dehydrogenation process in polycrystalline silicon (poly-Si) thin films. The dehydrogenation process was performed by using an in-situ CVD chamber in a N2 ambient or an ex-situ furnace in air ambient. We observed that the dehydrogenated poly-Si in a N2 ambient had a lower oxygen concentration than the dehydrogenated poly-Si annealed in an air ambient. The in-situ dehydrogenation increased the (111) preferred orientation of poly-Si and reduced the oxygen concentration in poly-Si thin films, leading to a reduction of the trap density near the valence band. This phenomenon gave rise to an increase of the field-effect mobility of the poly-Si thin film transistor.
关键词： Low-temperature poly silicon,Crystallization,Dehydrogenation,Thin film transistor
更新于2025-09-04 15:30:14
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Investigation on crystallization of CH3NH3PbI3 perovskite and its intermediate phase from polar aprotic solvents
摘要： Perovskite films are usually fabricated by solution-processed method due to its low cost and ease of fabrication. The organic solvent plays multiple roles in growth of perovskites. Here, we investigate the growth of methylammonium lead iodide perovskite and its intermediate phase from micro-droplets containing with various solvents. Perovskite intermediate phase inclines to grow in the direction of its (020) plane from polar aprotic solvents at low temperature. At high temperature, the growth of perovskites depends on the structure of solvent molecules. The intermediate phase still grows from the solvents with short chain structure. It tends to form smooth films containing radial domains with dimension in tens of microns, which consist of nanocrystals due to annealing effects. However, perovskite grains grow directly from the solvents with ring structure. It tends to form smooth thin films by joining the large hexagonal perovskite crystals together. It provides a guidance to prepare high quality perovskite films for high performance optoelectronic devices.
关键词： micro-droplet,polar aprotic solvent,perovskite,crystallization
更新于2025-09-04 15:30:14
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Multi-inch single-crystalline perovskite membrane for high-detectivity flexible photosensors
摘要： Single crystalline perovskites exhibit high optical absorption, long carrier lifetime, large carrier mobility, low trap-state-density and high defect tolerance. Unfortunately, all single crystalline perovskites attained so far are limited to bulk single crystals and small area wafers. As such, it is impossible to design highly demanded ?exible single-crystalline electronics and wearable devices including displays, touch sensing devices, transistors, etc. Herein we report a method of induced peripheral crystallization to prepare large area ?exible single-crystalline membrane (SCM) of phenylethylamine lead iodide (C6H5C2H4NH3)2PbI4 with area exceeding 2500 mm2 and thinness as little as 0.6 μm. The ultrathin ?exible SCM exhibits ultralow defect density, superior uniformity and long-term stability. Using the superior ultrathin membrane, a series of ?exible photosensors were designed and fabricated to exhibit very high external quantum ef?ciency of 26530%, responsivity of 98.17 A W?1 and detectivity as much as 1.62 × 1015 cm Hz1/2 W?1 (Jones).
关键词： high-detectivity,single-crystalline perovskite,flexible photosensors,induced peripheral crystallization,ultrathin membrane
更新于2025-09-04 15:30:14