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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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[IEEE 2019 IEEE International Conference on Electrical Engineering and Photonics (EExPolytech) - St. Petersburg, Russia (2019.10.17-2019.10.18)] 2019 IEEE International Conference on Electrical Engineering and Photonics (EExPolytech) - The Multi-Criteria Optimization in the LTspice Simulation Software of a JFet class AB Buffer Amplifier for Operation at Low Temperatures
摘要： A high-speed buffer amplifier (BA) for analog microcircuits field-effect transistors is proposed. The scheme differs from the known circuit solutions by a small number of elements and can operate within the range of cryogenic temperatures. In the LTSpice simulation software, the optimal control parameters were selected using the DEAP (Distributed Evolutionary Algorithm in Python) library of distributed evolutionary calculations and the NSGA-II multi-criteria optimization algorithm. Minimization of offset voltage, static current consumption and dead band width on the amplitude characteristic at low temperatures were chosen as the priority parameters of the control unit.
关键词： low-temperature electronics,class AB operation,optimization of analog electronic circuit,operational amplifier,LTspice environment,buffer amplifier,junction field-effect transistors
更新于2025-09-12 10:27:22
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Enhanced Lifetime and Photostability with Low‐temperature Mesoporous ZnTiO3/Compact SnO2 Electrodes in Perovskite Solar Cells
摘要： Perovskite solar cells (PSC) which have exceeded power conversion efficiencies (PCEs) of 25% are mainly demonstrated by using SnO2 or TiO2 as electron-transporting layers (ETLs). However, high-performance planar PSCs need precise process, which is difficult for large-scale production. Mesoporous structure shows better operability but with high-temperature process. Besides, as the most used mesoporous materials, the strong photocatalytic effect of TiO2 significantly limits the practical stability of PSCs under illumination (including ultraviolet light). Here we propose Zinc Titanate (ZnTiO3, ZTO) as mesoporous ETLs due to its weak photo-effect, excellent carrier extraction and transfer properties. Uniform mesoporous films were obtained by spinning coating the ZTO ink and annealed below 150°C. Photovoltaic devices based on Cs0.05FA0.81MA0.14PbI2.55Br0.45 perovskite sandwiched between SnO2-mesorporous ZTO electrode and Spiro-OMeTAD layer achieved the PCE of 20.5%. The PSCs retained more than 95% of their original efficiency after 100 days lifetime test without being encapsulated. Additionally, the PSCs retained over 95% of the initial performance when subjected at the maximum power point voltage for 120 h under AM 1.5G illumination (100 mW cm-2), demonstrating superior working stability. The application of ZTO provides a better choice for ETLs of PSCs. Moreover, the low temperature deposition method of inorganic ETL furnishes a way of low power consumption, large-scale and flexible preparation of PSCs.
关键词： perovskite solar cell,mesoporous ETL,photostability,ZTO,low-temperature
更新于2025-09-11 14:15:04
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Low-temperature solution-combustion-processed Zn-Doped Nb2O5 as an electron transport layer for efficient and stable perovskite solar cells
摘要： Niobium oxide (Nb2O5) has been demonstrated as an ideal electron transport layer (ETL) material for perovskite solar cells (PSCs) due to its excellent optical transmittance and high carrier mobility. Herein, a low-temperature (200°C) solution-combustion method is adopted to prepare the Nb2O5 film used as an ETL in PSCs. Under optimized conditions, PSC with the Nb2O5 ETL obtains a power conversion efficiency (PCE) of 16.40%. Moreover, we find that Zn-doping of Nb2O5 can further improve the efficiency of the device. As a matter of fact, the results show that a champion PCE of 17.70% can be achieved for the PSC with a 5 mol% Zn-doped Nb2O5 ETL. Significantly, both Nb2O5- and Zn-doped Nb2O5-based devices exhibit obviously better stability than the traditional high-temperature-sintered (~500°C) mesoporous TiO2-based devices, maintaining 80% of their initial PCE after storage in air for 20 days. In contrast, the PCE of the device with a TiO2 ETL quickly drops to 30% of its initial value after 13 days under the same storage condition. Consequently, this work suggests that using Zn-doped Nb2O5 ETL prepared by the low-temperature solution-combustion method is promising towards efficient and stable perovskite solar cells.
关键词： Perovskite solar cells,Electron transport layer,Zinc doping,Niobium oxide,Low-temperature synthesis,Stability
更新于2025-09-11 14:15:04
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AIP Conference Proceedings [AIP Publishing 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) - Fes, Morocco (25–27 March 2019)] 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) - Low-temperature silicon surface passivation for bulk lifetime studies based on Corona-charged Al2O3
摘要： Bulk lifetime studies of crystalline silicon wafers, e.g. with the aim of studying the light-induced degradation and regeneration behavior, require low-temperature surface passivation schemes that do not alter the silicon bulk properties, e.g. through hydrogenation. Aluminum oxide (Al2O3) can provide an excellent and stable surface passivation, however, in order to achieve the best possible surface passivation, an annealing step at ~400°C is typically required, which has been found to alter the bulk properties of some silicon materials. Hence, in this contribution we examine the possibility of passivating the silicon surface using Al2O3 layers that have seen a much lower thermal budget. We demonstrate that we are able to achieve an excellent silicon surface passivation using atomic-layer-deposited Al2O3 with measured effective surface recombination velocities Seff as low as 1.3 cm/s without exceeding a temperature of 250°C. We are able to achieve such excellent low-temperature passivation by applying a post-deposition annealing step at 250°C in combination with the deposition of negative Corona charges on the Al2O3 surface. For samples annealed at only 220°C, we still reach very low Seff values of 2 cm/s after deposition of negative Corona charges. We demonstrate that the Corona-charged low-temperature Al2O3 passivation shows only a slight degradation from an Seff of 1.6 cm/s to an Seff of 5 cm/s after 218 days of storage. Even without any post-deposition anneal and only negative Corona charges deposited, we achieve stable Seff values of 15 cm/s. As an alternative to Corona charging, a short exposure to intense UV light (λ = 395 nm) also significantly improves the surface passivation quality of low-temperature-annealed Al2O3-passivated silicon samples. However, the best surface passivation for the latter method is limited to an Seff value of 6.6 cm/s, which is still quite reasonable for bulk lifetime studies.
关键词： bulk lifetime studies,Al2O3,Corona charging,silicon surface passivation,low-temperature annealing
更新于2025-09-11 14:15:04
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An advanced approach to control the electro-optical properties of LT-GaAs-based terahertz photoconductive antenna
摘要： This work reports on an advanced approach to the design of THz photoconductive antenna (PCA). The LT-GaAs thin films used for the PCA fabrication were synthesized by MBE method on GaAs (100) substrate by adjusting the As pressure, As/Ga fluxes ratio, growth/annealing temperatures and annealing time. These parameters crucially affect electro-optical properties of the PCA samples as evidenced by the THz radiation power and time-domain spectroscopy measurements. The annealing temperature of 670 °C was found to be optimal for constructing a PCA possessing high amplitude of the THz radiation over the spectral range up to 1 THz at the resonance of 0.1 THz. The comparison of this PCA with the reference ZnTe crystal reveals a 2-fold increase in THz power. Furthermore, this antenna attains a 1.5-, 3-, and 2-fold increase in THz power, photocurrent efficiency, and actuating dc BV, as compared with the commercial ZOMEGA antenna. These results pave the way towards the creation of highly efficient LT-GaAs-based PCAs.
关键词： THz-antenna,Terahertz (THz) radiation,Photoconductive antenna (PCA),Low temperature-grown gallium arsenide (LT-GaAs),THz-spectroscopy
更新于2025-09-11 14:15:04
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[IEEE 2019 26th International Workshop on Active-Matrix Flatpanel Displays and Devices (AM-FPD) - Kyoto, Japan (2019.7.2-2019.7.5)] 2019 26th International Workshop on Active-Matrix Flatpanel Displays and Devices (AM-FPD) - Efficient Planar Perovskite Solar Cells with Entire Low-Temperature Processes via Brookite TiO <sub/>2</sub> Nanoparticle Electron Transport Layer
摘要： Electron transport layer (ETL) is well known as a crucial factor that affects power conversion efficiency (PCE) of perovskite solar cells (PSCs). Low temperature process on ETL has been highly considered for the future of low cost and roll to roll process in mass production of PSCs industrialization. Herein, we demonstrate the low-temperature (<180 oC) processes of pure phase, single crystalline brookite TiO2 nanoparticle (BK TiO2 NPs) layer as an ETL of PSCs, followed by different concentrations of TiCl4 treatment (20mM, 40mM, 60mM and 80mM). By using BK TiO2 NPs with the low temperature process (<180 oC), our device exhibited the highest power conversion efficiency of 15.49% in planar-type PSCs, indicating that the BK TiO2 NPs layer is a new candidate of ETL that can be fabricated in low temperature processes. The optimized TiCl4 concentration is 40mM for the surface treatment of BK TiO2 NPs, which results in the enhancement of PCE, reproducibility and the supression of hysteresis. Probably, the 40mM of TiCl4 treatment improves the interface between the perovskite and BK TiO2 NPs layers and promotes the efficient charge extraction. Thus, the present work is expected to provide an important technology to realize the low-cost planar PSCs produced in entire low-temperature processes.
关键词： electron transport layer,perovskite solar cells,TiCl4 treatment,brookite TiO2 nanoparticles,low-temperature processes
更新于2025-09-11 14:15:04
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Laser diagnostics for the electron density of helium low temperature plasmas using saturated absorption spectroscopy
摘要： Helium (He) low temperature plasma with an electron density higher than 10^11 cm^-3 was produced using an inductively coupled plasma source, and the electron density of this plasma was determined using a high-resolution laser spectroscopic technique. To remove the Doppler broadening which is the most dominant line broadening in low temperature plasmas, a saturated absorption spectroscopy system was configured. The Lamb dip was successfully separated from the Doppler broadening for the 2^1S - 4^1P transition of the He plasma using a high-resolution laser beam with a narrow spectral line width (below 1 MHz) at 396.5 nm. The estimated spectral line widths of natural broadening, van der Waals broadening, resonance broadening, and Stark broadening were 40.14 MHz, 0.93 MHz, 0.15 MHz, and 12.60 MHz, respectively, when the He gas pressure was 30 mTorr and 1 kW RF power was applied. The electron density of the He plasmas was determined to be ~3 x 10^11 cm^-3, which was comparable with those determined by a Langmuir probe and optical emission spectroscopy combined with a collisional-radiative model.
关键词： Low temperature plasma,Spectral line broadening,Saturated absorption spectroscopy,Helium
更新于2025-09-11 14:15:04
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Experimental Characterization of Polymer Surfaces Subject to Corona Discharges in Controlled Atmospheres
摘要： Polymeric dielectrics are employed extensively in the power transmission industry, thanks to their excellent properties; however, under normal operating conditions these materials tend to degrade and fail. In this study, samples of low-density polyethylene, polypropylene, polymethyl methacrylate, and polytetrafluoroethylene were subjected to corona discharges under nitrogen and air atmospheres. The discharges introduced structural modifications over the polymer surface. From a chemical perspective, the alterations are analogous among the non-fluorinated polymers (i.e., polyethylene (PE), polypropylene (PP), and polymethyl methacrylate (PMMA)). A simulation of the corona discharge allowed the identification of highly reactive species in the proximity of the surface. The results are consistent with the degradation of insulating polymers in high-voltage applications due to internal partial discharges that ultimately lead to the breakdown of the material.
关键词： partial discharges,chemical characterization,polymer surface degradation,morphological characterization,low-temperature plasma
更新于2025-09-11 14:15:04
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SUBSTRATE INTEGRATED WAVEGUIDE FILTER WITH IMPROVED STOPBAND PERFORMANCE USING LTCC TECHNOLOGY
摘要： A novel multi-layer third-order substrate integrated waveguide (SIW) bandpass ?lter with improved lower stopband performance is proposed. TE201-mode in folded-SIW cavity is utilized to implement negative cross coupling, and the TE101-mode is taken as a non-resonating node (NRN) for implementing bypass coupling. A circular aperture etched on the middle metal layer is used to realize coupling between source and the second SIW cavity. Then, three transmission zeros located below the passband can be obtained to improve stopband attenuation. Meanwhile, better spurious suppression performance above passband is achieved. A ?lter sample is designed and fabricated with multi-layer low-temperature co-?red ceramic (LTCC) technology. The measured S-parameters agree well with the simulated ones, with its predicted good performance.
关键词： transmission zeros,low-temperature co-?red ceramic (LTCC),Substrate integrated waveguide (SIW),bandpass ?lter,stopband performance
更新于2025-09-11 14:15:04
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Synthesis and luminescence properties of a novel dazzling red-emitting phosphor NaSr <sub/>3</sub> SbO <sub/>6</sub> :Mn <sup>4+</sup> for UV/n-UV w-LEDs
摘要： High-loading atomic cobalt (12.8 wt%) dispersed on nitrogen-doped graphene was successfully synthesized via considerably low temperature pyrolysis. The catalyst exhibits excellent electrocatalytic performance towards the oxygen reduction reaction with a large limiting diffusion current density of 5.60 mA cm?2 (10% higher than that of commercial Pt/C), and when acting as the air catalyst of Zn–air batteries, a high open-circuit voltage of 41.40 V and excellent power density are also achieved.
关键词： low-temperature pyrolysis,atomic cobalt,nitrogen-doped graphene,Zn–air batteries,oxygen reduction reaction
更新于2025-09-11 14:15:04