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Proton Irradiation on Cesium‐Fluoride‐Free and Cesium‐Fluoride‐Treated Cu(In,Ga)Se <sub/>2</sub> Solar Cells and Annealing Effects under Illumination
摘要： Several studies have been performed on proton irradiation onto alkali-metal untreated Cu(In,Ga)Se2 (CIGS) solar cells. However, there are almost no studies describing similar effects on alkali-treated CIGS solar cells. With this motivation, this work investigates proton irradiation and annealing effects under illumination on cesium-?uoride-free (CsF-free) and CsF-treated CIGS solar cells. Both CsF-free and CsF-treated CIGS solar cells degrade under proton irradiation. External quantum ef?ciency measurements show degradation in long wavelengths after the treatment. The experimental data are ?tted with a simulation, which show that proton-irradiated degradation is more severe at high ?uence. Capacitance–voltage measurements show a broadening of the depletion region after proton irradiation, which is due to the decreased net carrier concentration. It is proposed that proton irradiation at low ?uence generates shallow-type defects, whereas high-?uence protons generate deep defects. However, it is observed that room-temperature storage of the proton-irradiated solar cells causes partial recovery. Thermal annealing under illumination treatments is found to be bene?cial to the drastic recovery of the performance of solar cells irradiated at low ?uence. High-?uence proton-irradiated solar cells undergo minor recovery.
关键词： Cu(In,Ga)Se2 solar cells,cesium-?uoride,heat-light soaking,proton irradiation,annealing
更新于2025-09-11 14:15:04
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - High Efficiency Quantum Memory in Multiplexed Large-OD Cold Atomic Ensemble
摘要： Quantum memories enabling the storage of an input photonic qubit and its later retrieval with a ?delity beating any classical device constitute essential components in quantum communication networks and optical quantum information processing [1]. Our main goal is to develop a new generation of memories which have a near-unity ef?ciency for storage-and-retrieval operations, as well as high multiplexing capabilities. In the recent years, we demonstrated for instance the implementation for quantum bits encoded in the orbital angular momentum degree of freedom, which provides an essential capability for future networks with multimode capability [2]. We also realized multiple-degree-of-freedom memory, which can ?nd applications in classical data processing but also in quantum network scenarios where states structured in phase and polarization have been shown to provide promising attributes [3]. Recently, we realized a multiplexed quantum memory for polarization encoded qubits with high storage-and-retrieval ef?ciency [4]. We report on a quantum memory for polarization qubits that combines an average conditional ?delity above 99% and ef?ciency around 68%, thereby demonstrating a reversible qubit mapping where more information is retrieved than lost. The qubits are encoded with weak coherent states at the single-photon level and the memory is based on electromagnetically-induced transparency in an elongated laser-cooled ensemble of cesium atoms, spatially multiplexed for dual-rail storage. The reported ef?ciency approaches the maximal performance achievable on the D2 line transition used here, as shown by a comprehensive model that includes all the involved atomic transitions. In the alkali-metal atoms, hyper?ne interaction in the excited state indeed introduces several levels which can have a strong effect on the medium susceptibility via off resonant excitation, thereby decreasing the ef?ciency when the optical depth (OD) is large. As shown by this model, switching to the D1 line can increase the ef?ciency above 90%. Preliminary results with optical depth around 400 led us to a storage-and-retrieval ef?ciency of 85% at the single-photon level.
关键词： Large-OD,Quantum memory,Polarization qubits,Multiplexed,Cesium atoms,Cold atomic ensemble,Electromagnetically-induced transparency
更新于2025-09-11 14:15:04
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Thermal phase fluctuations in optically pumped dual-frequency vertical external-cavity surface-emitting lasers for cesium clocks based on coherent population trapping
摘要： A fully analytical model is established for the thermal fluctuations of the beatnote phase of an optically pumped dual-frequency vertical-external-cavity surface-emitting laser (VECSEL). This model starts with the resolution of the heat equation inside the semiconductor chip structure and follows with the evaluation of the induced thermo-optic phase shift. Both the fluctuations of the heat induced by the optical pumping and the thermodynamic fluctuations at room temperature are considered. On the one hand, the thermal response of the structure is investigated and a significant thermal lens effect caused by the pump is deduced. On the other hand, the power spectral density of the frequency noise is calculated in the presence of diffusion spatial anisotropy. The present model is in very good agreement with the phase noise measured for a dual-frequency VECSEL at 852 nm for application to metrology and the validity of the usual low-pass filter model is discussed.
关键词： coherent population trapping,vertical external-cavity surface-emitting lasers,optically pumped,thermal phase fluctuations,cesium clocks,dual-frequency
更新于2025-09-11 14:15:04
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Hot-substrate deposition of all-inorganic perovskite films for low-temperature processed high-efficiency solar cells
摘要： All-inorganic cesium lead halide perovskites (CsPbX3) have emerged as one of the most promising photovoltaic materials due to their superior thermal stability. However, the high phase transition temperatures (typically over 250 ?C) of CsPbX3 perovskites are incompatible with flexible substrates. Herein, we employed a simple hot-casting method to fabricate low-temperature processed CsPbI2Br films. By casting the perovskite precursor solution onto a hot substrate (maintained at 55 ?C), compact, large-grain and pinhole-free CsPbI2Br films can be prepared at a low post-annealing temperature, which outperform the conventional room temperature (RT)-casting and high-temperature (post-annealing at 340 ?C) processed CsPbI2Br films containing some voids. As a result, the hot-casting and low-temperature (post-annealing at 120 ?C) processed CsPbI2Br perovskite solar cells (PSCs) exhibited an outstanding power conversion efficiency (PCE) of 12.5%, which is much higher than that (2.91%) of the RT-casting processed CsPbI2Br devices. Further optimization of the post-annealing temperature (optimized value: 180 ?C) yielded the best performance of 13.8% for hot-casting processed CsPbI2Br devices. This study gives an effective and facile strategy toward low-temperature processed all-inorganic perovskite films and high-performance PSCs.
关键词： hot-casting method,All-inorganic cesium lead halide perovskites,perovskite solar cells,low-temperature processed,CsPbI2Br
更新于2025-09-11 14:15:04
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The Cesium doping using the nonstoichiometric precursor for improved CH3NH3PbI3 perovskite films and solar cells in ambient air
摘要： Organic-inorganic hybrid perovskite solar cells have shown great prospect as a low-cost and high efficiency photovoltaic technology. The quality of the perovskite absorber layer is most critical to the performance of the device, and the stability remains one of the challenging issues. In this paper, the Cesium (Cs) doping perovskite film was prepared from nonstoichiometric precursor solution in ambient and humidity-controlled conditions. The results showed that the crystallinity, uniformity, absorption, Photo-luminescence intensity and the thermal stability of these films can be effectively improved compared with the films fabricated from stoichiometric one, which is attributed to the combined effect of the Cs doping and excess methylammonium cations passivation. Finally, the highest efficiency of the perovskite solar cells fabricated from nonstoichiometric solution reached to 14.1%, which is 12.8% higher than that of the control device from stoichiometric solution (12.5%). Furthermore, the device displayed the high stability and efficiency degradation of only 2% occurring over a period of 5 weeks in ambient air without encapsulation. This reported work provides a pathway for further improving the performance of perovskite solar cells with higher stability.
关键词： Nonstoichiometric solution,Cesium doping,Stability,Organic-inorganic hybrid perovskite solar cells
更新于2025-09-11 14:15:04
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Excitonic Luminescence Engineering in Tervalent Europium Doped Cesium Lead Halide Perovskite Nanocrystals and Their Temperature-Dependent Energy Transfer Emission Properties
摘要： Cesium lead halide (CsPbX3 (X=Cl, Br, I)) perovskite nanocrystals (NCs) have revealed brilliant prospect in lighting, display and lasing fields owing to their excellent photoluminescence properties. To dope rare earth ions into halide perovskite, CsPbX3 (X=Cl, Br, I) NCs hosts not only inherit the excellent narrow linewidth excitonic properties but also yield unique photoluminescence emission. Herein, engineering of such excitonic luminescence is achieved in Eu3+ doped CsPbCl3-xBrx (x=0, 1, 1.5, 2, 3) solid solution NCs for the first time. The single doped-NCs present wide color gamut emission covering whole visible spectrum. Blue to green range (400-520 nm) emission is taken on by tunable excitonic photoluminescence of CsPbX3 NCs. Besides, there is a broad red spectra (590-700 nm) originating from emission of the tervalent europium ions in NCs. Meanwhile, a noticeable spin-polarized 5D0→7F1-6 emission of Eu3+ ions is acquired owing to energy transfer from excitons to dopants. Moreover, the energy transfer is temperature-dependent which originating from the increase of nonradiative transition probability, leading to decrease for the NCs hosts’ PL intensity, but increase for the PL intensity of dopants.
关键词： Eu3+ doped,excitonic luminescence,Cesium lead halide,energy transfer,perovskite nanocrystals
更新于2025-09-10 09:29:36
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[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Feasibility Study for Atomic Measurement of Microwave Strength at Arbitrary Frequencies Within the Full X-Band
摘要： In this paper, the double-resonance spectra of cesium atoms in a glass cell inserted in a WR-90 waveguide were obtained in DC magnetic fields with field strengths of tens of milliTesla. This result confirmed that the resonant lines at both ends of the double-resonance spectrum shifted to 8.24 GHz and 10.18 GHz, respectively, due to the Zeeman effect with the DC magnetic flux density of 40 mT. This result is useful as a feasibility study for the atomic measurement of a microwave strength at arbitrary frequencies within the full X-band.
关键词： Microwave bands,Atom optics,Cesium,Spectroscopy,Microwave measurement,Atomic measurements
更新于2025-09-10 09:29:36
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Dopants Control of Electron-Hole Recombination in Cesium-Titanium Halide Double Perovskite by Time Domain Ab Initio Simulation: Co-Doping Supersedes Mono-Doping
摘要： Using nonadiabatic (NA) molecular dynamics combined with time-domain density functional theory, we simulate electron-hole recombination in pristine and doped inorganic Pb-free double perovskite Cs2TiBr6. We show that replacing the titanium and/or bromine with silicon and/or chlorine extends the charge carrier lifetime. Importantly, dopants avoid deep traps despite they do not change the fundamental bandgap of Cs2TiBr6, they decrease the NA electron-phonon coupling and accelerate decoherence, arising from the reduced overlap of electron and hole wave functions as well as fast phonon modes induced by light dopants respectively, suppressing electron-hole recombination. More importantly, co-doping can reduce the formation energy of silicon and achieve higher doping concentration, potentially increasing the lifetime further. Our study suggests a rational strategy to reduce energy losses by co-doping in design of high performance all-inorganic Pb-free perovskite solar cells.
关键词： Co-doping,Electron-Hole Recombination,Mono-doping,Energy Conversion and Storage,Cesium-Titanium Halide Double Perovskite,Plasmonics and Optoelectronics,Time Domain Ab Initio Simulation,Dopants Control
更新于2025-09-10 09:29:36
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High-Temperature Cs <sub/>x</sub> C <sub/>58</sub> Fullerides
摘要： Cs doped non-IPR fullerides have been grown by co-depositing C58 cations and Cs atoms on HOPG. The C58 cages, as building blocks of the material, form a predominantly covalently stabilized scaffold, C58–C58, which is doped by Cs atoms thermally diffusing across the bulk. The heating of the solid CsxC58 sample is accompanied by sublimation of Cs, C58, and C60 species from the topmost layers of the sample. However, the major part (>94%) of the material survives the heating procedure and constitutes a doped high-temperature carbon solid, HT-CsxC58. The new non-IPR material exhibits surprisingly high thermal stability. It survives a heating flash up to 1100 K at which the classic IPR-CsxC60 phase does not exist anymore. However, the thermally treated HT-CsxC58 phase exhibits a considerably depleted Cs content (x < 2) and a significantly modified carbon scaffold. The apparent stability of the scaffold results from covalent C–C bonds interlinking adjacent carbon cages. Cs atoms in the HT-CsxC58 phase contribute to this stability only as minority species, forming comparably weak ionic bonds with C58–C58 oligomers. However, this interaction facilitates the formation of structural defects (new non-IPR sites) in carbon cages. The surface topography of the HT-CsxC58 as monitored by SPEM, AFM, and SEM is governed by islands standing out by their elevated Cs/C ratio.
关键词： X-ray photoelectron spectroscopy,fullerenes,desorption,isolated pentagon rule,cesium doping
更新于2025-09-09 09:28:46
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Room-temperature synthesis of Mn2+-doped cesium lead halide perovskite nanocrystals via a transformation doping method
摘要： Currently, Mn2+-doped cesium lead halide perovskite nanocrystals have attracted research interests. Here, we report a novel room-temperature transformation doping method for the synthesis of Mn2+-doped CsPbCl3 and CsPb(Br/Cl)3 nanocrystals. Innovatively, the transformation of Cs4PbX6 (X=Cl, Br) phase which has no excitation emission to CsPbX3 phase which has strong luminescence was used in this mechanism. Simply injecting MnCl2 precursor into Cs4PbX6 solution could result in the full transformation of Cs4PbX6 phase to CsPbX3 phase and Mn2+-doped CsPbCl3 or CsPb(Br/Cl)3 were obtained. The basic idea for the transformation doping method is that MnCl2 can not only drive the transformation of the two structures but also Mn2+ can substitute Pb2+. In this reaction, the concentration of Mn precursor is a key influence factor. Moreover, instead of the ligand of OA, the acetic acid was used in our method. Through the adjustment of the ligand in precursor, not just the photoluminescence quantum yields of as-prepared Mn2+-doped CsPbCl3 nanocrystals were improved from 7.8 to 32.6% (Mn2+-doped CsPb(Br/Cl)3 nanocrystals even could reach to 42.7%), the nanocrystals also retained outstanding stability. We propose a combination of structure transformation and ion doping as a perovskite doping mechanism. Our doping method is a novel strategy for lead halide perovskite nanocrystals doping project and it could provide more possibilities in the future.
关键词： photoluminescence quantum yields,Cs4PbX6,Mn2+-doped cesium lead halide perovskite nanocrystals,CsPbX3,room-temperature transformation doping method
更新于2025-09-09 09:28:46