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- 2019
- low-temperature electronics
- junction field-effect transistors
- differential operational amplifier
- LTspice environment
- differential stage
- common-mode rejection ratio
- class AB operation
- optimization of analog electronic circuit
- operational amplifier
- LTspice environment
- Electronic Science and Technology
- Don State Technical University
- Southern Federal University
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Theoretical Analysis of Hybrid Dense-Array Concentrator Photovoltaic and Stirling Engine System
摘要： In this paper, we analyse the performance of newly proposed hybrid dense-array concentrator photovoltaic (CPV) and gamma type low temperature differential (LTD) Stirling engine. Schmidt Analysis was applied to compute the performance of LTD Stirling engine while computational fluid dynamic was employed to simulate the heat transfer in the CPV receiver. The simulated result was subsequently used to determine the power conversion efficiency of the hybrid system. Three major parameters have been considered to optimize the overall system performance including water inlet temperature, water flow rate, and CPV surface temperature. In our theoretical analysis, the highest efficiency of the hybrid system ranging 37.8 - 38.0 % can be achieved at water inlet temperature of 90°C. It has shown significant improvement by producing 10.1 -10.7 % extra energy as compared to the efficiency of CPV system without waste heat recovery.
关键词： waste heat recovery,low temperature differential Stirling engine,Concentrator photovoltaic,conversion efficiency,Schmidt analysis,non-imaging dish concentrator
更新于2025-09-12 10:27:22
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Low Temperature Preparation of CsPbI2Br for Efficient and Stable Perovskite Solar Cells
摘要： Inorganic cesium-based perovskite is an alternative material of organic-inorganic perovskite because of its high thermal stability. However, the phase instability and the high annealing temperature to form α-phase hinder its further development. Herein, this work successfully achieves the reduction of α-phase formation temperature from 350oC to 150oC and achieves high performance CsPbI2Br-based perovskite solar cells via doping CH3COOCs (CsAc) at optimum concentration. The CsAc doped CsPbI2Br film fabricated at low temperature of 150oC exhibits good crystallization and pinhole-free surface. The function of phase stability by doping CsAc is the grain boundary passivation to decrease defect states and enhance the charge transport. The PSC based on CsAc doped CsPbI2Br using planar structure achieves an efficiency of 10.53%, which is three times higher than undoped CsPbI2Br fabricated at 150oC. More importantly, the pure α-phase with CsAc doped film shows long time stability. This work highlights an available method to prepare high performance and phase stable perovskite solar cells at low temperature.
关键词： passivation,solar cell,stability,inorganic perovskite,low temperature
更新于2025-09-12 10:27:22
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Solution‐Processed Molybdenum Oxide with Hydroxyl Radical‐Induced Oxygen Vacancy as an Efficient and Stable Interfacial Layer for Organic Solar Cells
摘要： The interfacial layer in organic solar cells (OSCs) can be an important boosting factor for improving device efficiency and stability. Herein, we provide a facile and cost-effective approach to form uniform molybdenum oxide (MoO3) film with desirable stability, based on solution processing at low temperature by simplified precursor solution synthesis. The solution-processed MoO3 (SM) film, with oxygen vacancies induced by the hydroxyl group, functions as an efficient anode interfacial layer in conventional OSCs. The hole transporting performance of SM is well demonstrated in PBDB-T:ITIC OSCs exhibiting over 10% of PCE. The enhanced device performance of SM-based OSCs over that of conducting polymer, PEDOT:PSS, is investigated by analyzing the morphology, electronic state, and electrical conductivity of such hole transporting layer, as well as the charge dynamics in the completed devices. Furthermore, the high stability of the SM films in OSCs is examined under various environmental conditions, including long-term and thermal stability. In particular, SM-based PBDB-T:PC71BM OSCs, maintain over 90% of their initial cell performance over 2,500 h under inert conditions. Our study shows that solution-processed metal oxides can be a viable interfacial layer with high functionality and versatility, overcoming the drawbacks of conventionally adopted conducting polymer interlayers.
关键词： stability,organic solar cells,versatility,metal oxide,low-temperature
更新于2025-09-12 10:27:22
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Influence of External Input Parameters on Species Production in a Dual-Frequency Capacitively Coupled Radio-frequency Oxygen Plasma
摘要： The impact of some external input parameters on electron, ozone O3, negative O? and positive O2+ ions, metastable singlet delta-state O2(a1Δg) molecule and atomic oxygen O formation is investigated using a numerical simulation. A one-dimensional, self-consistent fluid model of a dual radio-frequency capacitively coupled discharge operating on pure oxygen is developed to explore the evolution of the species density profiles as functions of gas pressure pg, driving high-frequency fhf, inter-electrode gap distance d and driving voltage waveform Vhf. The proposed model incorporates five main species and 24 dominant reaction channels. Simulation results show that the time-averaged density profiles of electron, ozone O3, negative O? and positive O2+ ions decrease when the gas pressure increases. However, the density of the metastable singlet delta-state O2(a1Δg) molecule and atomic oxygen O increase when the gas pressure increases. The electron density significantly increases with increased fhf until a maximum peak is reached at 40.68 MHz, and then it drops almost linearly at frequencies greater than 40.68 MHz. However, the negative ions O? density increases over a range of frequencies from 27.12 to 67.80 MHz, then it decreases slightly as fhf increases further. Therefore, when fhf increases, it does enhance the production of the metastable O2(a1Δg) and the oxygen O atoms, whereas the O2+ density is decreased. It is also shown that an increase in the inter-electrode gap distance causes a noticeably decrease in the formation of the various species in the discharge. Furthermore, a significant increase in the atomic oxygen O and the metastable singlet delta-state O2(a1Δg) densities is displayed as Vhf increases. Comparisons are made with recent simulation models and experimental data, and a qualitative agreement is obtained.
关键词： Low-temperature plasma,Dual capacitively coupled oxygen plasma,Species production
更新于2025-09-12 10:27:22
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Comprehensive analysis of blue diode laser-annealing of amorphous silicon films
摘要： The low temperature polycrystalline silicon (LTPS) method has proved to be a technical breakthrough, accomplishing semiconductor thin films with remarkable mobility for a range of high-performance displays, including liquid crystal display and organic light emitting diodes. However, utilizing a conventional excimer laser source for LTPS incurs high cost. In this paper, we demonstrate a comprehensive analysis of the crystallization mechanism of a-Si film (94 nm) and the thermal deformation of the glass substrate induced by Blue diode Laser Annealing (BLA). BLA provides high quality laterally grown crystals over 4 μm × 10 μm on glass substrates, which were examined by optical microscopy, scanning electron microscopy, and Raman spectroscopy. In addition, the permanent deformation introduced by the annealing process is numerically modeled, instantiating how to control the heat conduction from the thin film that affects the substrate. Our findings reveal that the permanent thermal deformation depth that can be obtained is comparable to the roughness of the silicon film for the optimum scanning speed and laser power. The combination of both experimental and numerical results elucidates the manifested physical mechanisms during the BLA process and provides the guidelines to improve the experimental parameters of this process.
关键词： Lateral grain growth,Glass deformation,Silicon thin film,Low Temperature Polycrystalline Silicon (LTPS),Blue diode laser
更新于2025-09-12 10:27:22
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A low-temperature TiO2/SnO2 electron transport layer for high-performance planar perovskite solar cells; 低温 TiO2/SnO2 双电子传输层的光电性能及其在 钙钛矿电池中的应用;
摘要： Conventional titanium oxide (TiO2) as an electron transport layer (ETL) in hybrid organic-inorganic perovskite solar cells (PSCs) requires a sintering process at a high temperature to crystalize, which is not suitable for flexible PSCs and tandem solar cells with their low-temperature-processed bottom cell. Here, we introduce a low-temperature solution method to deposit a TiO2/tin oxide (SnO2) bilayer towards an efficient ETL. From the systematic measurements of optical and electronic properties, we demonstrate that the TiO2/SnO2 ETL has an enhanced charge extraction ability and a suppressed carrier recombination at the ETL/perovskite interface, both of which are beneficial to photo-generated carrier separation and transport. As a result, PSCs with TiO2/SnO2 bilayer ETLs present higher photovoltaic performance of the baseline cells compared with their TiO2 and SnO2 single-layer ETL counterparts. The champion PSC has a power conversion efficiency (PCE) of 19.11% with an open-circuit voltage (Voc) of 1.15 V, a short-circuit current density (Jsc) of 22.77 mA cm?2, and a fill factor (FF) of 72.38%. Additionally, due to the suitable band alignment of the TiO2/SnO2 ETL in the device, a high Voc of 1.18 V is achieved. It has been proven that the TiO2/SnO2 bilayer is a promising alternative ETL for high efficiency PSCs.
关键词： electron transport layer,low temperature,perovskite solar cell,energy band alignment,TiO2/SnO2
更新于2025-09-12 10:27:22
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Measurement and Analysis of Noise Spectra in Terahertz Wave Detection Utilizing Low-Temperature-Grown GaAs Photoconductive Antenna
摘要： Noise power spectral density (NPSD) in time domain terahertz (THz) wave detection systems utilizing GaAs-based photoconductive antennas (PCAs) was investigated quantitatively. The contributions of the PCA noise and the amplifier noises at the amplifier output depend strongly on the resistance of the PCA, the circuit parameters, and the frequency. The PCA has two types of noise: one can be modeled by the Johnson-Nyquist (thermal) noise for the PCA resistance, while the other has an NPSD inversely proportional to the frequency with its intensity dependent on the properties of the GaAs and the metallization. At a high frequency range ~ 100 kHz, voltage-type amplifier noise could appear if the cable capacitance between the PCA and the amplifier is large. As a result, a low-noise range tends to appear in the intermediate frequency range. In comparison with the PCAs with Ti/Au metallization, the PCAs with Pd/Ge/Ti/Au having lower contact resistance lead to lager influence of the Johnson-Nyquist noise at the output.
关键词： Thermal noise,Noise spectra,Photoconductive antenna,Low-temperature-grown GaAs,1/f noise
更新于2025-09-12 10:27:22
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A study on the material characteristics of low temperature cured SnO2 films for perovskite solar cells under high humidity
摘要： Electron transport layer (ETL) plays a crucial role on the fabrication of perovskite solar cells (PSCs) by separating and transporting the charge carriers. Titanium dioxide (TiO2) has been extensively used as an ETL in PSCs; however, high temperature thermal annealing requirement impedes its integration with flexible polymer substrates for roll to roll fabrication. Herein, we have demonstrated that SnO2 is a potential ETL candidate when fabricated at low temperature (180 °C) using spin coating technique. XRD and XPS analysis revealed synthesis of rutile SnO2 tetragonal phase. TEM micrographs with SAED pattern proved formation of nanosized (3 to 4 nm) crystals of SnO2 with polycrystalline phase. FESEM analysis revealed the SnO2 nanocrystals fully covered the FTO surface and elemental mapping confirmed the uniformly distribution tin (Sn) and (O) elements throughout the surface. In addition to this, transmission analysis confirmed that SnO2 film exhibited good transmission property. PSCs were fabricated in ambient air (relative humidity ranges from 55% to 65%) with concentrated SnO2 colloidal solution and diluted SnO2 with different concentrations (1:1 v/v, 1:2 v/v, 1:4 v/v and 1:6 v/v). It was found that 1:4 v/v based diluted colloidal solution of SnO2 in DI water film exhibited the highest PSC performance of 8.51% in ambient conditions. Thus, low temperature solution processed SnO2 is an efficient ETL and well-suited for low cost automated fabrication of PSCs at large scale.
关键词： Perovskite solar cells,SnO2,Low temperature,High humidity,Electron transport layer
更新于2025-09-12 10:27:22
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Micro tuning of wide-bandgap perovskite lattice plane for efficient and robust high-voltage planar solar cells exceeding 1.5 V
摘要： Iodide-free tribromide based perovskites, with their wide bandgap of over 2.0 eV, are highly regarded as potential candidates for a photoelectrochemical water splitting system and the topmost cell in tandem solar cell. Herein, we report on the importance of micro tuning of crystal-lattice by cesium incorporation into A-site on low temperature processed formamidinium lead tribromide (CH(NH2)2PbBr3 = FAPbBr3) perovskite films. The partial incorporation of cesium bromide (CsBr) in to FAPbBr3 film tunes crystal-lattice interactions, resulting in a high-purity cubic crystal system with preferred orientation. An entirely low temperature processed planar photovoltaic device assembled with FAPbBr3 containing 8% Cs (Cs0.08FA0.92PbBr3) exhibited an optimum PCE (power conversion efficiency) of 8.56% with a Voc (open-circuit voltage) of 1.516 V, which is higher than the PCE of 7.07% and Voc of 1.428 V of the FAPbBr3 device. Photoluminescence-intensity and temporal-imaging measurements were conducted by laser scanning confocal time-resolved microscopy (LCTM), which revealed that CsBr incorporation into a FAPbBr3 film significantly suppresses the non-radiative recombination pathways and homogenizes the spatial distribution of photoluminescence. It was visualized that the incorporation of CsBr in FAPbBr3 directly affects the bulk defect and photoluminescence properties, which provides evidence that Cs ions surely alleviate the segregation and aggregation of ions in the perovskite film. Notably, the Cs0.08FA0.92PbBr3 film, with a carrier lifetime of about 270 ns, exhibited a 1.37-fold longer radiative recombination time than that (210 ns) observed for the FAPbBr3 film. Furthermore, aging experiments without encapsulation under ambient (in air for 2000 h) and severe (65 °C and 65% RH for 500 h) conditions revealed that the Cs0.08FA0.92PbBr3 devices were more robust than the FAPbBr3 devices.
关键词： Low-temperature process,High-photovoltage,Wide-bandgap,CsBr,FAPbBr3
更新于2025-09-12 10:27:22
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Investigation of Low Temperature Processed Titanium Dioxide (TiO2) Films for Printed Dye Sensitized Solar Cells (DSSCs) for Large Area Flexible Applications
摘要： This paper reports a systematic study of the effect of nano-crystalline titanium dioxide (TiO2) formulations and annealing temperature conditions on the performance of dye sensitized solar cells (DSSCs) realized on fluorine tin oxide (FTO) glass substrates. DSSC fabrication is restricted to high temperature (>150 oC) process-compatible materials by the nano-crystalline process of the TiO2. DSSCs benefit from the use of lower cost materials and offer higher efficiency than organic solar cells but high processing temperatures limit their application on, for example, textile substrates. The aim of this study is to develop and optimize a low temperature processable TiO2 formulation suitable for both screen printing and spray coating. The results from this paper can be applied in future fabrication processes on flexible plastic and fabric substrates. The challenge of this research work is to achieve the smooth deposition and processing at 150 oC of TiO2 layers on glass substrates. We report a maximum DSSC efficiency of 4.3 % achieved by screen printing and 2.5 % achieved by spray coating on a glass substrate using the new low temperature process.
关键词： low temperature TiO2,Dye sensitized solar cells,flexibe solar cells
更新于2025-09-12 10:27:22