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Selectively Photocatalytic Oxidation of Low Concentration Methane over Graphitic Carbon Nitride Decorated Tungsten Bronze Cesium
摘要： Although the traditional thermal catalysis is usually used to convert the methane into value-added products, its high reaction temperature results in low performance-price ratio in conversion of low concentration methane. In this regard, we synthesized a series of mace-like g-C3N4 decorated Cs0.33WO3 nanocomposites for photocatalytic conversion of low concentration methane under mild conditions. The optimized g-C3N4@Cs0.33WO3 (weight ratio = 3:7) photocatalyst selectively converted low concentration methane (1000 ppm) into methanol with yield of 4.38 μmol/h/g under light irradiation and at room temperature. Both performance experiments and trapping experiments verified that the methane activation and methyl oxidation involved in photocatalytic conversion process of methane. The ?O2- firstly activated the methane to methyl on the surface of the g-C3N4 in the composite and then the photogenerated electrons from the Cs0.33WO3 in the composite inhibited the peroxidation and increased the generation of methanol. This research provides a new route to design and synthesize photocatalysts for converting methane into value-added chemicals.
关键词： Selective Conversion,Low concentration methane,Tungsten Bronze Cesium,Photocatalytic Methane Conversion,Graphic Carbon Nitride
更新于2025-09-19 17:15:36
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10.34%-efficient integrated CsPbBr3/bulk-heterojunction solar cells
摘要： Inorganic cesium lead bromide (CsPbBr3) perovskite solar cells (PSCs) have superior moisture- and thermal-stability in comparison with organic-specie or/and I-containing devices. However, the narrow-spectra absorption (<550 nm) arising from their large bandgap of 2.3 eV for CsPbBr3 halide has markedly limited the further efficiency enhancement of corresponding inorganic device, therefore a great challenge is to broaden the light response range without sacrificing environmental tolerances. In this work, we constructively fabricate a CsPbBr3/bulk-heterojunction (organic J61-ITIC) photoactive layer to widen the optical absorption range of inorganic CsPbBr3 based interlayer-free device. Arising from the broadened light response wavelength from 550 to 780 nm and precisely optimized crystal lattice by incorporating Rb into CsPbBr3 film, the optimal device achieves a power conversion efficiency up to 10.34% under one sun illumination. Upon persistent attacks by heat of 80°C (0% humidity) or 90% humidity (25°C) over 40 days, the solar cell can still remain approximately 96% of initial efficiency, demonstrating the excellent stability for practical application.
关键词： Inorganic perovskite solar cell,Wide-spectral absorption,Cesium lead bromide,Photoactive layer,Improved stability
更新于2025-09-19 17:13:59
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Component Regulation and Crystallization Mechanism of CsPbBr3/Cs4PbBr6 Perovskite Composite Quantum Dots-Embedded Borosilicate Glass for Light Emitting Application
摘要： Cesium lead bromide CsPbBr3/Cs4PbBr6 perovskite composite QDs-embedded borosilicate glass (QDs@glass) have been prepared by using the conventional melting-quenching and heat-treatment technique. The effect of raw components and melting condition on the crystallization process, phase transition and crystal growth of CsPbBr3/Cs4PbBr6 QDs in the glass matrix were discussed in details. The formation of Cs4PbBr6 in glass has a significant impact on the optical properties of CsPbBr3 QDs. Excellent QDs@glass with high photoluminescence quantum yield (PLQY) of ～58% was achieved by optimizing the raw components and melting condition. The obtained QDs@glass shows outstanding thermal stability, photostability and water resistance stability. The PL intensity of QDs@glass remains 80% of the original one after being stored in a chamber with high-temperature and high-humidity (85 °C/RH 85%) for 70 hours, and shows little decrease (2%) after being soaked into deionized water for 70 hours. The white LED fabricated by using the as-synthesized green QDs@glass powder and red K2SiF6: Mn4+ phosphor on the surface of a blue LED chip displays luminous efficiency of 25 lm/W with CIE coordinates of (0.3328, 0.3442) at 100 mA and exhibits a wide color gamut (130% of the National Television System Committee standard).
关键词： Quantum dots,Borosilicate glass,White LED,Display,Cesium lead bromide
更新于2025-09-19 17:13:59
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LiBa <sub/>4</sub> Ga <sub/>5</sub> Q <sub/>12</sub> (Q = S, Se): Noncentrosymmetric Metal Chalcogenides with a Cesium Chloride Topological Structure Displaying a Remarkable Laser Damage Threshold
摘要： The exploration of novel infrared nonlinear optical (IR NLO) materials with large second-harmonic generation (SHG) responses and wide band gaps has become very imperative recently. Herein we reported two noncentrosymmetric compounds, LiBa4Ga5Q12 (Q = S, Se), crystallizing in space group P421c (No. 114), which feature 3D frameworks built by a basic [Ga5Q16]17? windmill cluster and LiQ4 tetrahedra in a cesium chloride topological structure. Both compounds satisfy the desired balance between good SHG responses (～1.5× that of AgGaS2) and wide band gaps (3.43 and 2.44 eV) with remarkable laser damage thresholds (21× and 6× that of AgGaS2). The theoretical calculations uncover that the [Ga5Q16]17? cluster makes major contributions to the SHG e?ect in LiBa4Ga5Q12. In addition, the structure?performance relationship among all compounds in the I?II4?III5?VI12 system has been discussed systematically, which indicates that the introduction of the alkali metal lithium in the I site is bene?cial for the production of large band gaps. This work will be helpful in exploring novel IR NLO materials with special structures and comprehensive properties in the chalcogenide system.
关键词： chalcogenides,infrared nonlinear optical materials,laser damage thresholds,cesium chloride topological structure,second-harmonic generation
更新于2025-09-19 17:13:59
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Large-Area Cesium Lead Bromide Perovskite Light-Emitting Diodes Realized by Incorporating a Hybrid Additive
摘要： Encouraging progresses have been made in the development of solution processable perovskite light-emitting diodes (PeLEDs). However, the related fundamental physics of the efficient operation of the large area PeLEDs is still far from adequate. In this work, we report our recent effort in developing a high-performance large area cesium lead bromide (CsPbBr3) PeLEDs through a controlled growth of CsPbBr3 emission layer using a hybrid additive in the CsPbBr3 precursor solution. The hybrid additive comprises a combination of poly(ethylene oxide) (PEO) and cesium carbonate (Cs2CO3). We found that the performance of the CsPbBr3 PeLEDs, prepared using the precursor solution having a hybrid additive of PEO and Cs2CO3, is superior to that of the control PeLEDs, prepared using a pure CsPbBr3 precursor solution in two ways: (1) it helps to suppress both the structural defects and non-radiative recombination-induced leakage current, and (2) it assists in improving the electron-hole current balance. The 1.0×1.5 cm2-sized PeLEDs having a maximum luminance of > 104 cd/m2 has been demonstrated, which is more than three times greater than that of a control PeLED prepared using a pure CsPbBr3 precursor solution (3.0×103 cd/m2).
关键词： hybrid additive,cesium lead bromide,perovskite light-emitting diodes,large area
更新于2025-09-19 17:13:59
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Low-temperature Interfacial Engineering for Flexible CsPbI2Br Perovskite Solar Cells with High Performance Beyond 15%
摘要： All-inorganic cesium lead halide (CsPbX3) perovskites exhibit superior thermal stability compared to the organic-inorganic hybrid counterparts. The power conversion efficiency (PCE) of CsPbI2Br perovskite solar cells (PSCs) has been over 16%. However, the high-temperature annealing limits its feasibility on flexible devices. Here, low-temperature processed flexible CsPbI2Br PSCs are designed by introducing Al-doped ZnO (AZO) as an electron-transport layer and tert-butyl cyanoacetate (t-BCA) as a passivation layer. The thickness-insensitive AZO significantly enhances the quality of perovskite films and the reproducibility of the PSCs. As well the t-BCA can effectively passivate the trap states and suppress charge recombination of CsPbI2Br films. The as-optimized flexible CsPbI2Br PSCs exhibits a high PCE of 15.08% (with the active area of 0.1 cm2), which is one of the highest efficiency for flexible all-inorganic PSCs. The devices show outstanding stability, retaining 93% of the original PCE after being stored 60 days, 91% and 86% of the initial efficiency after continuously heating 360 hours at 85 oC and stored under 65% RH for 30 hours, respectively. In addition, the PSCs exhibits excellent mechanical stability, remains 85% of original value after 1000 bending cycles at a curvature radius of 3 mm.
关键词： perovskite solar cells,tert-butyl cyanoacetate,passivation layer,All-inorganic cesium lead halide,flexible devices,low-temperature processed,Al-doped ZnO
更新于2025-09-19 17:13:59
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Tri-functionalized TiO Cl4-2 accessory layer to boost efficiency of hole-free, all-inorganic perovskite solar cells
摘要： Tin dioxide (SnO2) is generally regarded as a promising electron-transporting layer (ETL) for state-of-the-art perovskite solar cells (PSCs), however, the ubiquitous oxygen-vacancy-related defects at SnO2 surface and the large energy difference between conduction band of SnO2 and perovskite layer undoubtedly cause severe charge carrier recombination, resulting in sluggish charge extraction efficiency and non-negligible open-circuit voltage (Voc) loss. Herein, a chlorine-containing TiOxCl4-2x accessory layer is fabricated by immersing SnO2 layer into the TiCl4 aqueous solution to passivate the surface oxygen-vacancy-related defects of SnO2 layer and to set an intermediate energy level at ETL/perovskite interface in all-inorganic cesium lead tri-bromine (CsPbBr3) PSCs. Furthermore, the TiOxCl4-2x layer also improves the infiltration of SnO2 layer surface toward perovskite precursor for high-quality perovskite film. Finally, the hole-free, all-inorganic CsPbBr3 PSC with a structure of FTO/SnO2/TiOxCl4-2x/Cs0.91Rb0.09PbBr3/carbon achieves a champion efficiency of 10.44% with a Voc as high as 1.629 V in comparison to 8.31% for control device. Moreover, the optimized solar cell presents good stability in 80% humidity in air.
关键词： Electron-transporting layer,Stability,All-inorganic perovskite solar cells,Charge recombination,Cesium lead bromine
更新于2025-09-19 17:13:59
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[IEEE 2018 International Topical Meeting on Microwave Photonics (MWP) - Toulouse (2018.10.22-2018.10.25)] 2018 International Topical Meeting on Microwave Photonics (MWP) - Strategies for noise reduction of a dual-frequency VECSEL dedicated to cesium CPT clocks
摘要： We investigate the strategies to reduce the noise of a class-A dual-frequency vertical external cavity surface emitting laser (VECSEL) operating at Cesium clock wavelength. We focus mainly on the beatnote phase noise of the two orthogonally polarized modes emitted. Within the framework of coupled rate equations, we show that the phase noise spectrum of the beatnote is well described by considering both the phase–amplitude coupling and the thermal effects. The spearhead of this study consists in ?rst theoretically evidencing reduction strategies for the phase noise beatnote by optimizing the physical parameters of the model and then experimentally demonstrating its feasibility by using two in-phase fully–correlated beams pumping each mode separately. Possible ways to decrease the intensity noises are also identi?ed.
关键词： vertical external cavity surface emitting laser,Dual-frequency laser,intensity noise,cesium clock,phase noise
更新于2025-09-16 10:30:52
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Single-Pass Laser Frequency Conversion to 780.2 nm and 852.3 nm Based on PPMgO:LN Bulk Crystals and Diode-Laser-Seeded Fiber Amplifiers
摘要： We report the preparation of a 780.2 nm and 852.3 nm laser device based on single-pass periodically poled magnesium-oxide-doped lithium niobate (PPMgO:LN) bulk crystals and diode-laser-seeded fiber amplifiers. First, a single-frequency continuously tunable 780.2 nm laser of more than 600 mW from second-harmonic generation (SHG) by a 1560.5 nm laser can be achieved. Then, a 250 mW light at 852.3 nm is generated and achieves an overall conversion efficiency of 4.1% from sum-frequency generation (SFG) by mixing the 1560.5 nm and 1878.0 nm lasers. The continuously tunable range of 780.2 nm and 852.3 nm are at least 6.8 GHz and 9.2 GHz. By employing this laser system, we can conveniently perform laser cooling, trapping and manipulating both rubidium (Rb) and cesium (Cs) atoms simultaneously. This system has promising applications in a cold atoms Rb-Cs two-component interferemeter and in the formation of the RbCs dimer by the photoassociation of cold Rb and Cs atoms confined in a magneto-optical trap.
关键词： single-pass sum-frequency generation,fiber amplifier,rubidium D2 line (780.2 nm),single-pass second-harmonic generation,cesium D2 line (852.3 nm)
更新于2025-09-16 10:30:52
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Stable and Higha??Efficiency Methylammoniuma??Free Perovskite Solar Cells
摘要： Organic–inorganic metal halide perovskite solar cells (PSCs) have achieved certified power conversion efficiency (PCE) of 25.2% with complex compositional and bandgap engineering. However, the thermal instability of methylammonium (MA) cation can cause the degradation of the perovskite film, remaining a risk for the long-term stability of the devices. Herein, a unique method is demonstrated to fabricate highly phase-stable perovskite film without MA by introducing cesium chloride (CsCl) in the double cation (Cs, formamidinium) perovskite precursor. Moreover, due to the suboptimal bandgap of bromide (Br?), the amount of Br? is regulated, leading to high power conversion efficiency. As a result, MA-free perovskite solar cells achieve remarkable long-term stability and a PCE of 20.50%, which is one of the best results for MA-free PSCs. Moreover, the unencapsulated device retains about 80% of the original efficiencies after a 1000 h aging study. These results provide a feasible approach to enhance solar cell stability and performance simultaneously, paving the way for commercializing PSCs.
关键词： methylammonium free,perovskite solar cells,lead bromide,thermal stability,cesium chloride
更新于2025-09-16 10:30:52