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Bright Blue Light Emission of Ni2+ ions doped CsPbClxBr3-x Perovskite Quantum Dots Enabling Efficient Light-Emitting Devices
摘要： In recent years, significant advances have been achieved in the red and green perovskite quantum dots（PQDs）based light-emitting diodes (LEDs). However, the performances of the blue perovskite LEDs are still seriously lagging behind that of the green and red counterparts. Herein, we successfully developed Ni2+ ions doped CsPbClxBr3-x PQDs through the room-temperature supersaturated recrystallization synthetic approach. We simultaneously realized the doping of various concentrations of Ni2+ cations, and modulated the Cl/Br element ratios through introducing different amount of NiCl2 solution in the reaction medium. By the synthetic method, not only the emission wavelength from 508 to 432 nm of Ni2+ ions doped CsPbClxBr3-x QDs was facially adjusted, but also the photoluminescence quantum yield (PLQY) of PQDs was greatly improved due to efficiently removing the defects of the PQDs. Thus, the blue emission at 470 nm with PLQY of 89% was achieved in 2.5% Ni2+ ions doped CsPbCl0.99Br2.01 QDs, which increased nearly three times over that of undoped CsPbClBr2 QDs, and was the highest for the CsPbX3 PQDs with blue emission that fulfilling the NTSC standards. Benefiting from the high luminous Ni2+ ions doped PQDs, the blue emitting LED at 470 nm was obtained, exhibiting an external quantum efficiency (EQE) of 2.4% and a maximum luminance of 612 cd/m2, which surpassed the best performance reported previously for the corresponding blue-emitting PQDs based LED.
关键词： perovskite QD-LEDs,Ni2+ ion doping,blue emission,anion exchange,perovskite quantum dots
更新于2025-09-23 15:21:01
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Controllable synthesis of transition metal ion-doped CeO2 micro/nanostructures for improving photocatalytic performance
摘要： Ceria (CeO2) micro/nanostructures with various sizes and shapes were successfully synthesized by doping with a series of transition metal ions without any surfactant or template. The crystal structure, morphology, and photocatalytic performance of CeO2 and Co-, Zr-, Cu-doped CeO2 were characterized. The lattice parameters, which indicate the crystal structure distortion and change of Ce4+, were changed by incorporating a transition metal into the CeO2. Doping with transition metal ion could broaden the absorption range from ultraviolet to visible region and enhance the concentration of oxygen vacancies, which exhibited a significantly lower optical band than pure CeO2. The photocatalytic studies revealed that CeO2 with a spate of oxygen vacancies displayed a higher photocatalytic activity than pure CeO2 in degrading the organic pollutant rhodamine B (RhB). Furthermore, the O2? and ?OH radicals formed during photocatalysis process were revealed by means of nitrotetrazolium blue chloride (NBT) reduction method and a terephthalic acid (TA) fluorescence probe method, respectively, which discovers that radicals were crucial for the degradation of RhB. The H2-TPR confirmed that a small amount of transition metal ions significantly affected the oxidation state of the surface cations and oxygen vacancies. This study clearly reveals the effects of different transition metal ion dopants on the morphologies and photocatalytic performance of transition metal ion-doped CeO2 micro/nanostructures.
关键词： oxygen vacancy,CeO2,metal ion-doping,morphology,photocatalytic activity
更新于2025-09-23 15:19:57
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Microfibers Doped with Perovskite Nanocrystals for Ultralow-Loss Waveguides
摘要： Low loss optical waveguides have attracted intense interests as the building blocks for photonic devices and integrated circuits. Herein, we employed the all-inorganic halide perovskite nanocrystals (IHPNs) doped polymer microfibers for developing the active waveguides for the first time. We reveal that the absorption coefficient (2.6 cm-1) of the CsPbBr3 IHPNs-doped polymer fibers is one order of magnitude lower than that of traditional CdSe quantum dots (QDs)-based microfibers, which can be attributed to the much higher photoluminescence quantum yield of IHPNs. Moreover, manganese ions (Mn2+) were successfully inserted into CsPbX3 IHPNs to engineer the Stokes shift and eliminate the reabsorption effect. As a result, the Mn:CsPb(Br/Cl)3 IHPNs-doped polymer microfibers exhibited a record-low absorption coefficient of 0.33 cm-1. These findings reveal a great potential of perovskite nanocrystals in photonic technologies that also paves the way for solution-processed QDs in low-loss and long-range optical guiding.
关键词： Stokes shift,perovskite nanocrystals,polymer microfibers,Low-loss waveguides,ion doping
更新于2025-09-16 10:30:52
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Synergistic Improvements in Efficiency and Stability of 2D Perovskite Solar Cells with Metal Ion Doping
摘要： 2D perovskites hold a great prospective to create highly efficient and stable solar cell devices. In order to explore their full potential, every component of 2D perovskite solar cells (PSCs) has to be carefully designed and engineered. Herein, the metal ion doping strategy is taken to optimize both the hole transport layers (HTLs) and the light absorbing layers of the BA2MA3Pb4I13 (BA = butylamine; MA = methylammonium) based 2D PSC devices. The hole extraction and transport abilities are significantly enhanced by Cu ion doping in the nickel oxide layers, while the optoelectronic properties of the BA2MA3Pb4I13 layers are effectively improved with Cs ion doping. The synergistic incorporations of Cu and Cs ions have boosted the device power conversion efficiency to 13.92%, the highest for 2D PSCs based on inorganic HTLs. In addition, the inorganic nature of the Cu doped nickel oxide film and the high quality of the Cs doped 2D perovskite film also endow the PSC device with extraordinary humidity and thermal stabilities.
关键词： 2D perovskites,metal ion doping,stability,solar cells
更新于2025-09-12 10:27:22
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Multi-mode optical coded patterns enabled by upconversion nanoparticles and photonic crystals
摘要： The Al-Zr-ZnO films was deposited on the surface of n-Si (111) by sol-gel method. The results showed that the average grain size of Al-Zr-ZnO films decreases due to ion doping concentration. Based on XPS analysis, the surface defect oxygen of Al-Zr-ZnO films decreases. As for graphene/ Al-Zr-ZnO Schottky contact, barrier height increased and ideality factor decreased with the increasing of Al ion or Zr ion doping, indicating that the rectifying characteristics of graphene/Al-Zr-ZnO Schottky contacts was enhanced due to ion co-doping. It can be explained that oxygen vacancies of Al-Zr-ZnO films decreases due to the ion doping and weakens Fermi level pinning.
关键词： sol-gel method,Ion doping,Al-Zr-ZnO films,electrical properties,graphene
更新于2025-09-11 14:15:04
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Enhanced H2S sensing performance of cobalt doped free-standing TiO2 nanotube array film and theoretical simulation based on density functional theory
摘要： A cobalt doped free-standing TiO2 nanotube (Co-doped TiNT) array film was firstly synthesized by a one-step anodization followed by immersion method. The characterization analysis results of TiNT with the field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD) and X-ray photoelectron spectra (XPS) proved that the doped cobalt ions had entered into the lattice of TiO2. Subsequently, the Co-doped TiNT gas sensors with different concentration of cobalt ions were developed for testing the gas-sensing properties for H2S. Compared with the undoped one, by 0.1 M Co-doping operation, working under the temperature of 300 °C, the Co-doped TiNT gas sensor was demonstrated the following superiorities: the response time and recovery time were 14 s and 4 s, which were shortened by 36.4% and 33.3%, respectively. Moreover, the Co-doped TiNT gas sensor with superior selectivity, stability and repeatability, reached the response value at 199.16 for 50 ppm H2S, which was improved by 7.6 times. Finally, based on the density functional theory (DFT), the calculated band gap of the Co-doped TiO2 decreased from 2.285 eV to 1.418 eV with a 38% decline. The mechanism simulation explained the obtained promotions in the gas sensing properties of the Co-doped TiNT gas sensor.
关键词： Cobalt ion doping,H2S gas sensor,Highly sensitivity,TiO2 nanotube array film,Density functional theory
更新于2025-09-10 09:29:36
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Microstructural, optical, and electrical characteristics of Ni/C doped BST thin films
摘要： In the present work the effect of simultaneous doping of carbon and nickel on the microstructural, optical, and electrical properties of barium strontium titanate (BST) is investigated. Thin films of BST were prepared by the sol-gel method in six different compositions ((Ba0.6Sr0.4)(NixCyTi1-x-y)O3): x = y = 0.00 (BST), x = 0.04 y = 0.00 (BST4N), x = 0.04 y = 0.01 (BST4N-1C), x = 0.04 y = 0.02 (BST4N-2C), x = 0.04 y = 0.03 (BST4N-3C), and x = y = 0.04 (BST4N-4C). Structural features and chemical bonds of the films were studied by TGA/DSC, XRD, FT-IR, and FE-SEM. The electrical and optical properties of the films were analysed by impedance spectroscopy and UV–VIS spectroscopy. The results show that addition of Ni and C leads to Ti4+-Ni2+ and Ti4+-C4+ replacements, respectively. These replacements lead to a gradual increase in the band gap energy; from 3.15 eV for BST to 3.44, 3.5, 3.66, 3.73 and 3.76 eV for BST4N, BST4N-1C, BST4N-2C, BST4N-3C, and BST4N-4C, respectively. In contrast, the dielectric loss decreases significantly from 0.055 for BST to 0.031, 0.033, 0.03, 0.022 and 0.01 for BST4N, BST4N-1C, BST4N-2C, BST4N-3C, and BST4N-4C, respectively. At the same time, the quality factor Qf (1/ tanδ) increases substantially from 15 for BST to 32, 30, 33, 44 and 87 for BST4N, BST4N-1C, BST4N-2C, BST4N-3C, and BST4N-4C, respectively. In contrast, the frequency dependence of the capacity decreases in comparison to un-doped BST. Among all films, the BST4N-4C had the highest figure of merit (FOM), least dielectric loss, and very low frequency-dependence, making it the best candidate for tuneable device applications.
关键词： Ion doping,Sol-gel,Thin-film,BaSrTiO3,Dielectric properties,Optical properties
更新于2025-09-09 09:28:46