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The study on saturation current and ideality factor of CdTe solar cell based on CdS window layer deposited with hydrogen peroxide
摘要： By adding hydrogen peroxide (H2O2) to the solution, a more compact cadmium sulfide (CdS) film with larger optical band gap is fabricated by chemical bath deposition method. The oxidation of CdS is confirmed by the formation of cadmium sulfate (CdSO4) in the CdS window layer via x-ray photoelectron spectroscopy investigation. The analysis of quantum efficiency considering the alloy CdS1?yTey shows that the oxygenated CdS suppress the S-Te interdiffusion, which promotes the spectral response in short-wave range. Moreover, this oxygenated CdS layer promoted the conversion efficiency of the cadmium telluride (CdTe) based solar cell from11.2% to 14.0% due to the improvement of open-circuit voltage and the fill factor. The transport mechanisms of saturation current are evaluated by temperature dependent current–voltage curves. Results show that the oxygenated window layer reduces both the interfacial and bulk recombination, thus improves the ideality factor. The decrease of bulk recombination in depletion region is attributed to the fewer trap level induced from S-Te interdiffusion. The decrease of interfacial recombination is attributed to the larger optical band gap of oxygenated CdS, which results in a spike-like conduction band alignment at CdS/CdTe heterojunction.
关键词： saturation current,CBD,open-circuit voltage,ideality factor,CdS:O/CdTe heterojunction,hydrogen peroxide
更新于2025-09-19 17:13:59
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A Comprehensive Review of Optical Fiber Refractometers: Toward a Standard Comparative Criterion
摘要： Thanks to the peculiarities of optical fiber and its ability to be combined with nanotechnology, precise and accurate measurements of the changes in optical properties (i.e., refractive index) of the medium surrounding the fiber are becoming possible with a high degree of performance. Thus, optical fiber sensors (OFSs) are increasingly finding applications in biochemistry and biomedicine. Here, all types of optical fiber refractometers are covered, and they are classified into three main groups: interferometers, grating-based structures, and resonance-based structures (the resonance is induced by coating the optical fiber sensor with a thin film). The performance of these different structures is compared by means of the most common parameters: sensitivity, full width at half minimum or maximum, figure of merit, and quality factor. The aim here is to provide a reliable and easy-to-use tool to compare the performance of the most recent developments on fiber optic refractometers.
关键词： resonance-based structures,quality factor,refractometers,optical fiber sensors,grating-based structures,sensitivity,figure of merit,interferometers
更新于2025-09-19 17:13:59
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Optimal Photonic Crystal Cavities for Coupling Nanoemitters to Photonic Integrated Circuits
摘要： Photonic integrated circuits that are manufactured with mature semiconductor technology hold great promise for realizing scalable quantum technology. Efficient interfaces between quantum emitters and nanophotonic devices are crucial building blocks for such implementations on silicon chips. These interfaces can be realized as nanobeam optical cavities with high quality factors and wavelength-scale mode volumes, thus providing enhanced coupling between nano-scale quantum emitters and nanophotonic circuits. Realizing such resonant structures is particularly challenging for the visible wavelength range, where many of the currently considered quantum emitters operate, and if compatibility with modern semiconductor nanofabrication processes is desired. Here, it is shown that photonic crystal nanobeam cavities for the visible spectrum can be designed and fabricated directly on-substrate with high quality factors and small mode volumes. Designs are compared based on deterministic and mode-matching methods and the latter is found advantageous for on-substrate realizations. The results pave the way for integrating quantum emitters with nanophotonic circuits for applications in quantum technology.
关键词： CMOS compatible,photonic crystal cavities,integrated photonics,high quality factor
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Large Area 21.6% Efficiency Front Junction N-type Cell with Screen Printed Tunnel Oxide Passivated Poly-Si Rear Contact
摘要： Blind interference alignment (BIA) can greatly improve the degree of freedom with the infinite signal-to-noise ratio (SNR) assumption. Under the finite SNR condition, noise accumulation can have a significantly negative impact on SNR, inducing severe performance deterioration. In particular, in multi-cell networks, the transmitter to which a user connects can further affect its received SNR and the BIA design. To address such problem, we present a user grouping scheme for reducing noise accumulation in a single cell and analyze the impact of transmitter connections on the user grouping scheme. SNR BIA in a multi-cell network is further proposed, which jointly optimizes the transmitter connection and the user grouping scheme. Extensive simulations demonstrate that the achievable sum rate of SNR BIA is 1.36 times, 1.66 times, and 2.68 times that of data shared BIA, standard BIA, and extended BIA reported in the literature, respectively, and SNR BIA is more robust to user mobility.
关键词： transmitter connection,SNR reduced factor,effective degree of freedom,Blind interference alignment
更新于2025-09-19 17:13:59
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Prickly pear fruit extract as photosensitizer for dye-sensitized solar cell
摘要： In this study, we have explored prickly pear fruit extract as a photosensitizer in dye-sensitized solar cells (DSSC). The photosensitizer was isolated from prickly pear fruits by extraction method using ethanol as solvent. Structural, morphological and optical properties of prickly pear extract characterized by XRD, SEM, UV-VIS-DRS, FTIR spectra, respectively. UV-VIS absorption and FTIR spectra of prickly pear fruit extract confirm the presence of betacyanin and hydroxyl groups anchoring onto the TiO2 surface. The absorption maxima at 534 nm in the visible region is prominent. The presence of betacyanin in the extract is indicative that the dye will be useful as a sensitizer in DSSC. Reflectance edge of TiO2 is red-shifted upon the adsorption of natural dye. The XPS analysis showed the charge state of hydroxyl (O-H) groups that are attached with the natural dye adsorbed onto the surface of TiO2. The fabricated DSSC had a conversion efficiency (?) of 0.56 % with highest fill factor (FF) of 85.0%, open-circuit voltage (Voc) of 0.56 V and short circuit-current density (Jsc) with 1.17 mA/cm2. The value obtained for the fill factor is promising to further explore the prickly pear extract for applicability in DSSC by improving the efficiency.
关键词： Dye-sensitized solar cells,Hydroxyl groups,Prickly pear fruit extract,Photosensitizer,TiO2,Fill factor,Betacyanin,Conversion efficiency
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE Industry Applications Society Annual Meeting - Baltimore, MD, USA (2019.9.29-2019.10.3)] 2019 IEEE Industry Applications Society Annual Meeting - LED Power Factor and Quality Factor
摘要： This paper presents the LED power factor and quality factor simply characterized from the available terminal average current, average voltage, and RMS current to evaluate the electric power quality of LEDs. The LED average power is composed of the bandgap power and the resistive power due to the forward voltage and equivalent series resistor in the LED approximate linear circuit, respectively. The forward voltage and equivalent series resistor are characterized from the available terminal average current, average voltage, and RMS current to calculate the bandgap power and the resistive power. The LED power factor and quality factor are calculated from the bandgap power, resistive power and average power to evaluate the electric power quality of LEDs. Using a single-branch LED approximate linear circuit and a high-order LED piece-wise linear circuit, two verification examples, respectively, are demonstrated to calculate their LED power factor and quality factor.
关键词： light-emitting-diode,average power,root-mean-square,average current,forward voltage,resistive power,bandgap power,power factor,rms,LED,quality factor
更新于2025-09-16 10:30:52
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[IEEE 2019 International Conference on Power, Energy and Innovations (ICPEI) - Pattaya, Chonburi, Thailand (2019.10.16-2019.10.18)] 2019 International Conference on Power, Energy and Innovations (ICPEI) - The control of large scale grid-tied photovoltaic rooftop systems to avoid the power factor charge
摘要： Large scale grid-tied photovoltaic (PV) rooftop systems are encouraged to install in many commercial buildings with the aim to saving the electricity energy bills. However, the support from PV system normally reduces only real power consumption while the use of reactive power is unchanged. In consequent, the power factor at the point of common coupling (PCC) may drop below the utility’s prescribed value, causing the increase of power factor charge in the energy bill. The power factor correction by controlling reactive power supplied by PV rooftop system is presented in this work. The performances of this proposed control method are examined based on time-sweep load flow calculations on DIgSILENT PowerFactory software. The simulation results show that the reactive power compensation by PV interfaced converter, with smart control algorithm, can improve the power factor at the PCC effectively, without adding new compensation devices.
关键词： Grid-tied inverter control,photovoltaic rooftop system,power factor charge,power factor correction,reactive power compensation
更新于2025-09-16 10:30:52
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[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Comparative Study on the Influence of Quantum Dot Display and Liquid Crystal Display on Human Visual Function
摘要： Previous studies have shown that liquid crystal display (LCD) can cause visual fatigue to the human eye, but the effect of quantum dot (QD) display has not been explored yet. This study conducted a human factor experiment on the QD display and LCD. The parameters ACC, HOAs and MTF were selected as objective physiological indicators for visual quantification of visual fatigue. 39 participants performed a 45-minute video viewing task. While before and after the visual task, measured the physiological parameters of the participants' eyes. Analysis the effects of QD display and LCD on human physiological characteristics under the same conditions. The results show that: (1) The QD display and LCD have an influence on the physiological characteristics of the human eye during continuous visual task duration. These effects can be quantified by changes in human eye physiological parameters; (2) The effect of QD display on human eye physiological parameters is less than LCD: the VICO index (visual comfort index) is lower, and the participants' color feedback accuracy is higher. This study provides theoretical basis and data support for the subsequent development of quantum dot display.
关键词： Quantum dot display,Human eye physiological characteristics,Visual comfort index,Liquid crystal display,Human factor experiment
更新于2025-09-16 10:30:52
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Revelating mechnism of light ideality factor in organic solar cells
摘要： Light ideality factor, the slope of open-circuit voltage versus the logarithm of the illumination intensity, is a topic of continuing debate in solar cells. However, the generally accepted interpretation of the ideality factor will fail when the factor is larger than 2. This work demonstrates that the mechanism for light ideality factor is degeneracy of carriers by using the generalized Einstein coefficient in the drift-diffusion model. Moreover, this work proposes that the light ideality factor should satisfy the relation of 0:1:2:4 under different illumination conditions. This work challenges the generally accepted interpretation of the ideality factor and provides a better understanding of organic solar cells.
关键词： degeneracy of carriers,generalized Einstein relation,organic solar cells,light ideality factor
更新于2025-09-16 10:30:52
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[IEEE 2019 International Ural Conference on Electrical Power Engineering (UralCon) - Chelyabinsk, Russia (2019.10.1-2019.10.3)] 2019 International Ural Conference on Electrical Power Engineering (UralCon) - Development of Method for Photovoltaic Generation Control by Electrical Network Relative Power Losses Minimization Criteria
摘要： In recent years, the world practice shows that in many developed countries the use of renewable energy sources has become an important factor for the sustainable development of their energy sector. The integration of solar power plants into the electric networks is one of the most important directions for the development of energy, but the issue of the influence of solar generation on the modes of electric distribution networks and the relative power loss is acute. This paper analyzes the effect of distributed solar generation on power losses and the configuration of the load curve. The problem of excessive solar generation at the weekend causes the flow of active power from the consumer to the power system, which leads to a change in the configuration of the load curve and an increase in the relative power losses. A calculation method is proposed to minimize relative power losses in electric networks, which allows improving the efficiency of the electric grid company in the conditions of integration of distributed solar generation. Also, to confirm the correctness of the calculation results of the proposed method, variational calculations were carried out.
关键词： Shape factor,Power losses,Load curve,Republic of Tajikistan,Solar generation
更新于2025-09-16 10:30:52