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Novel Ca20Al26Mg3Si3O68:Ce3+,Tb3+ phosphors: preferential site occupation, color-tunable luminescence and device application
摘要： A novel luminescence material of emitting color-tunable Ca20Al26Mg3Si3O68(denoted as CAMSO):Ce3+,Tb3+ phosphors have been synthesized via the high temperature solid-phase reaction process. The crystal cell structure, photoluminescence properties and application performance such as thermal stability and LED device performance of the phosphors were researched in detail. CAMSO:Ce3+,Tb3+ phosphors showed multi-color with the different concentration of Ce3+ and Tb3+ ions. Although the concentration of Ce3+ ions was settled and there was the existence of energy transfer from Ce3+ to Tb3+ ions, it was found that Ce3+ ions’ blue light emission intensity showed abnormal increasing with the increase of Tb3+ ions doping concentration. The irregular phenomenon was discussed in detail. The phosphor CAMSO:0.2Ce3+, 0.1Tb3+ photoluminescence emission intensity motivated by 374nm at 150oC retained about 81% of that measured at room temperature, which demonstrating the good thermal and color stability of the sample. In addition, the white LED lamps were fabricated through mixing the sample CAMSO:0.2Ce3+,0.2Tb3+ and the commercial phosphor CaAlSiN3:Eu2+ and their performance has been measured. The results show that this series of phosphors could be excellent candidates for the application of UV-excited w-LEDs.
关键词： thermal stability,abnormal luminescence,tunable color,multi-crystallographic sites
更新于2025-09-23 15:22:29
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Self-Powered Humidity Sensor Using Chitosan-Based Plasmonic Metal-Hydrogel-Metal Filters
摘要： A tunable Fabry–Pérot resonator is realized using metal–insulator–metal structure, in which the insulator is chitosan hydrogel. The chitosan swells in response to changes in relative humidity; this change affects transmissive structural color of the multilayer structure. This tunable resonator is utilized for a humidity sensor combined with a photovoltaic cell. The change in current through the photovoltaic cell provides rapid precise measurement of relative humidity, and the change in color of the multilayer provides an approximate, remotely-readable estimate. The response requires no power, so the device has numerous sensing applications.
关键词： Fabry–Pérot etalon,structural colors,tunable color filter,tunable structural colors,interferometric colors,metal–insulator–metal
更新于2025-09-23 15:19:57
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Tuning the Color Palette of Semi-Transparent Solar Cells via Lateral ??-Extension of Polycyclic Heteroaromatics of Donora??Acceptor Dyes
摘要： Durable solar cells with tunable color and diaphaneity are very promising for building integrated photovoltaic applications. In this paper we employ donor–acceptor organic dyes U3, U4, U5, and R6 featured by polycyclic heteroaromatics 6,12-dihydroindeno[1,2-b]indeno[2',1':4,5]thieno[2,3-d]thiophene (IT2), 7,15-dihydrobenzo[6',7']indeno[2',1':4,5]thieno[3,2-b]benzo[6,7]indeno[2,1-d]thiophene (BIT2), 7,15-dihydrophenaleno[1,2-b]phenaleno[2',1':4,5]thieno[2,3-d]thiophene (PT2), and 9,19-dihydrobenzo[1',10']phenanthro[3',4':4,5]thieno[3,2-b]benzo[1,10]phenanthro[3,4-d]thiophene (BPT2) to fabricate semi-transparent dye-sensitized solar cells (DSSCs). The U3, U4, U5, and R6 based cells are goldenrod, crimson, red, and sapphire blue, with power conversion efficiencies of 3.5%, 8.2%, 7.6, and 10.1% at the AM1.5G conditions. Density functional theory calculation and voltammetric measurement reveal that lateral π-extension of polycyclic heteroaromatic brings forth a downward displacement of lowest unoccupied molecular orbital, affording a high molar extinction coefficient, low-energy gap blue dye. Femtosecond fluorescence decay measurements of dyed titania and alumina films unravel the electron injection yields of photo-excited dye molecules, which are well correlated with the maximal values of external quantum efficiencies of DSSCs. After 1,000 h full sunlight soaking at 60 oC, the red and blue DSSCs exhibit stable photocurrents, owing to the strong bonding and photochemical stability of dye molecules adsorbed on the surface of titania as well as the retention of close-to-unity electron collection yield.
关键词： electron injection,durability,tunable color,semi-transparent solar cell,lateral π-extension,photosensitizer
更新于2025-09-23 15:19:57
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Cs <sub/>4</sub> PbBr <sub/>6</sub> /CsPbBr <sub/>3</sub> perovskite composites for WLEDs: pure white, high luminous efficiency and tunable color temperature
摘要： Cs4PbBr6/CsPbBr3 perovskite composites are fabricated by room-temperature one-pot mixing synthesis, which is short in time, free from inert gases and delivers a high product yield. Temperature-dependent photoluminescence shows that a larger exciton binding energy of 291.1 meV exhibits better thermal stability compared with that of pure Cs4PbBr6 and CsPbBr3 materials. The CIE chromaticity coordinates (0.1380, 0.7236) of green LEDs designed with Cs4PbBr6/CsPbBr3 perovskite composites show almost no variation under driving current changing from 5 to 30 mA. Furthermore, the ground Cs4PbBr6/CsPbBr3 perovskite composites mixed with red emitting K2SiF6:Mn4+ phosphor are dropped and casted on a blue-emitting InGaN chip. The white light emitting diodes (WLEDs) are presented, which have good luminous e?ciency of 65.33 lm W(cid:1)1 at 20 mA, a correlated color temperature of 5190 K, and the white gamut with chromaticity coordinate of (0.3392, 0.3336). According to the state of art, these excellent characteristics observed are much superior to the reported results of conventional perovskite-based WLEDs, which demonstrate the immense potential and great prospect of Cs4PbBr6/CsPbBr3 perovskite composites to replace conventional phosphors in lighting devices.
关键词： WLEDs,luminous efficiency,tunable color temperature,Cs4PbBr6/CsPbBr3 perovskite composites
更新于2025-09-16 10:30:52
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Electrospinning Construction of Flexible Composite Nanoribbons with Color-Tunable Fluorescence
摘要： Herein, we describe the innovative one-dimensional nanomaterials, electrospun composite nanoribbons (width 10.119 ± 0.186 μm) containing complexes of Eu(TTA)3(TPPO)2 and Tb(BA)3phen in a matrix of polymethylmethacrylate (PMMA). Scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and fluorescence spectroscopy were used to characterize the final products. The novel luminescent composite nanoribbons exhibit green, orange and red fluorescence emission peaks at 490, 545, 592, and 615 nm, which are ascribed to the 5D4 → 7F6 (490 nm) and 5D4 → 7F5 (545 nm) energy transitions of Tb3+ ions, and the 5D0 → 7F1 (592 nm), 5D0 → 7F2 (615 nm) transitions of Eu3+ ions, respectively. It is observed that the doping percentage and the chosen excitation wavelength could be used to tune the emission color of the samples. The color-tunable luminescent composite nanoribbons have potential applications in the fields of display panels, lasers and bioimaging.
关键词： fluorescence,electrospinning,composite nanoribbons,rare earth complexes,tunable color
更新于2025-09-10 09:29:36