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Material Property Changes in Defects Caused by Reverse Bias Exposure of CIGS Solar Cells
摘要： Partial shading of Cu(In,Ga)Se2 modules can lead to the formation of reverse bias induced wormlike defects. These wormlike defects act as local shunts and permanently decrease module output. A good understanding of the formation and propagation mechanisms of these defects is needed in order to mitigate the negative effects, or to prevent these defects from forming. In this article, wormlike defects were formed on small nonencapsulated cells by exposing them to reverse bias conditions. Scanning electron microscopy-energy-dispersive X-ray spectroscopy measurements showed a rearrangement of elements: Indium, gallium, and copper were replaced by cadmium, whereas selenium was replaced by sulfur in the area around the defect. Moreover, additional electronic-defect levels were found in that area with spectrally resolved photoluminescence spectroscopy. Based on the material changes in the area close to the wormlike defects, a propagation mechanism is proposed. The model assumes a chemical reaction as the driving force for propagation instead of melting because of ohmic heating.
关键词： photoluminescence (PL),photovoltaic (PV) cells,electric breakdown,reliability,thin film devices,Cadmium
更新于2025-09-12 10:27:22
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Nonlinear Optical Properties of Zinc Oxide Thin Films Produced by Pulsed Laser Deposition
摘要： In this work, the nonlinear optical properties of Zinc Oxide (ZnO) thin films produced on microscope slide glass substrates at room temperature (RT) using Pulsed Laser Deposition (PLD) method has been presented. PLD system consists of a vacuum chamber (pumped by a turbo molecular pump, backed with a rotary pump), rotating sample and substrate holders, optical thickness measurement system, infrared temperature measurement system and a nanosecond laser system. Previously deposition vacuum chamber evacuated down to ~10-8 mbar and deposition was taken place about 1.3×10-1 mbar oxygen background gas pressure value. Morphological properties of thin films were obtained by Atomic Force Microscopy (AFM) that shows homogenous and smooth film structure. Thin films crystallinity were investigated by using X-Ray Diffraction (XRD) method and showed that polycrystalline ZnO structure with the largest peak corresponding to (002) orientation but some films contain Zn with (101) orientation . The thicknesses of the films were deduced from reflectance measurement using a fitting software and crosschecked with profilometer and AFM measurements. The thickness of the films ranged between 10 nm and 220 nm. Linear optical properties were obtained by using UV-VIS Spectrometer. Furthermore, we presented the nonlinear optical properties of the ZnO thin films that were obtained by the z-scan method.
关键词： Z-scan system,Zinc Oxide Thin Film,Nonlinear Optical Properties,Pulsed Laser Deposition
更新于2025-09-12 10:27:22
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SILAR Controlled CdS Nanoparticles Sensitized CdO Diode Based Photodetectors
摘要： In this research, we have produced Al/CdS nanoparticles-CdO/p-si/Al photodetetor and investigated its optical and electrical characteristics for various optoelectronic applications. The CdO thin film was covered by using sol-gel spin coating method onto the silicon, followed by CdS nanoparticles constitution by the help of SILAR technique. In order to examine the morphological and optical characteristics of fabricated photodetector, the field emission scanning electron microscopy and UV-Vis spectroscopy were utilized, and the band gap of the prepared film was determined as 2,17 eV with the help of these analyzes. The current behavior against the varying voltage values were investigated for the different intensities of solar light conditions and the significant diode parameters were computed by the use of this measurements. As a result of this computation, the barrier height value was found to be 0.49 eV while the ideality factor value was 3.2, and the photoresponse of the photodetector was measured as approximatelly 2.65 × 103. Besides, the transient photocurrent and photocapacitance charactersitics were examined for distinct light conditions. Finally, the interface states were calculated from the capacitance/conductance–voltage (C/G–V) measurements.
关键词： Optical characteristics,SILAR method,Sol-gel method,CdO thin film,Electrical characteristics,CdS nanoparticles
更新于2025-09-12 10:27:22
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Relationships between design parameters of see-through thin film photovoltaic facade and energy performance of office building in China cold zone
摘要： See-through thin film photovoltaic is a substitute for traditional glass in building facade. Three design parameters of photovoltaic facade have the vast influence on the overall energy performance of building. They are orientation, visible light transmittance and comprehensive heat transfer coefficient. In this study, six photovoltaic facades were established by using two kinds of thin film photovoltaic materials with different transmittances, followed by conducting the simulations of ultimate energy consumptions, in five orientations, of the offices located in Tianjin city which belongs to China cold zone. Then, according to the energy consumption of the reference office, the energy-saving rates of offices with photovoltaic facades are calculated. Finally, the sensitivity of each design parameter to the energy-saving rate of buildings is analyzed. The results indicate that when building photovoltaic fa?ade faces south, the highest energy-saving rate is up to 61.22%, and the lowest energy-saving rate is only 13.7% when the PVF looks east. The energy-saving rate of the room is most sensitive to the orientation, and the sensitivity of the three design parameters changes as the orientation changes. When the photovoltaic facade faces south, according to the sensitivity of the parameters from high to low, the order should be orientation, the comprehensive heat transfer coefficient and the visible light transmittance.
关键词： building energy performance,see-through thin film photovoltaic fa?ade,sensitivity analysis,numerical simulation
更新于2025-09-12 10:27:22
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Development of Textured Electrode, Index Matching Layer and Nanostructured Materials for Light Trapping inside Photovoltaic devices
摘要： In order to reduce the energy harvesting cost, numerous efforts have been made to replace crystalline silicon solar cells with thin film based solar cells. The device efficiency of thin film photo-voltaic devices needs to be improved. Currently, surface texturing based light trapping technologies have been used to improve the device efficiency of photo-voltaic devices. In this paper, we demonstrate experimentally that surface textured hydrogenated ZnO:Al films as transparent conducting oxide (TCO) electrode and nanostructured materials in solar cells improve the anti-reflection properties of TCO coated glass substrate. These surfaces scatter the incident light inside the active layer of solar cells. Scattering of light on textured and nanostructured surface causes increase in average light path length inside active layer which results in increased absorption coefficient. Amorphous silicon solar cells fabricated on textured TCO layer show increase in device efficiency. Silicon nitride film was used as index matching layer between glass and TCO and increase in transmittance was observed. Silicon nanowires were grown using PECVD for their application in solar cells. Metal (Indium) nanoparticles were used for plasmonic light trapping inside solar cells. It was observed that textured TCO, index matching layer and plasmonic nanoparticles techniques improve the device efficiency while nanowires based devices need more optimization to get higher efficiency.
关键词： Plasmonic Light Trapping,Nano-Particles,Thin Film Solar Cell,Surface Texturing,Silicon Nanowires
更新于2025-09-12 10:27:22
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Solution-Processed Oxide Complementary Inverter via Laser Annealing and Inkjet Printing
摘要： Metal–oxide–semiconductors (MOS) have become an ideal candidate for the next-generation optoelectronic device applications. However, high processing temperature and complicate processes are still tremendous challenge in developing solution-based complementary MOS (CMOS) inverter. In this article, for the first time, femtosecond (fs) laser was used to realize controllable annealing for solution-based CMOS inverter. The achievement of nonstoichiometric p-type oxide thin films was ascribed to the photo-assisted conversion of precursor to metal–oxide (M–O) lattices along with the formation of atom vacancies in oxide lattice due to carrier excitation and relaxation using laser annealing (LA). The field effect mobility of the p- and n-type M–O thin-film transistors (TFTs) with inkjet printing (IJP) and LA was 0.91 and 7.07 cm2/V·s, respectively. Moreover, location control capacity was exploited to separately anneal the p- and n-type oxide deposited with IJP for the fabrication of TFTs, which significantly simplified the fabrication process of the inverter. CMOS inverter with high noise margin and moderate voltage gain above 10 was also obtained. Our work significantly improved the ability to selectively manipulate the functionality and properties of the irradiated materials. The results demonstrated that logic gates based on all-oxide can be large area integrated using our strategy, exhibiting attractive properties and applications of the CMOS integrated circuits in oxide electronics.
关键词： p-type oxide semiconductor,inkjet printing (IJP),Complementary inverter,femtosecond (fs) laser annealing (LA),thin-film transistors (TFTs)
更新于2025-09-12 10:27:22
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Investigation of the photovoltaic performance of n-Zno/n-CdS/p-Cu <sub/>2</sub> ZnSnS <sub/>4</sub> solar cell
摘要： The semiconducting thin film solar cell based on Cu2ZnSnS4 (CZTS) materials is considered as a promising candidate for very large-scale application due to high absorption coefficient and low cost. In this study, the performances of n-ZnO/n-CdS/p-CZTS solar cells were numerically simulated using the AFORS-HET software. The influences of double-graded bandgap and thickness of CZTS layer on the performances of the solar cell were investigated. The calculated results show that double-graded bandgap structure can greatly optimize the conversion efficiency of CZTS thin film solar cell. The optimal dual gradient structure is 1.4 eV-1.3 eV-1.5 eV, the optimal thickness ratio is 11:1, and the conversion efficiency could be 26.63%. The results of this study can serve as a guide in fabricating CZTS solar cell.
关键词： thin film solar cell,double-graded bandgap,Cu2ZnSnS4,light absorption
更新于2025-09-12 10:27:22
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Using Deep Machine Learning to Understand the Physical Performance Bottlenecks in Novel Thin‐Film Solar Cells
摘要： There is currently a worldwide effort to develop materials for solar energy harvesting which are efficient and cost effective, and do not emit significant levels of CO2 during manufacture. When a researcher fabricates a novel device from a novel material system, it often takes many weeks of experimental effort and data analysis to understand why any given device/material combination produces an efficient or poorly optimized cell. It therefore takes the community tens of years to transform a promising material system to a fully optimized cell ready for production (perovskites are a contemporary example). Herein, developed is a new and rapid approach to understanding device/material performance, which uses a combination of machine learning, device modeling, and experiment. Providing a set of electrical device parameters (charge carrier mobilities, recombination rates, trap densities, etc.) in a matter of seconds thus offers a fast way to directly link fabrication conditions to device/material performance, pointing a way to further and more rapid optimization of light harvesting devices. The method is demonstrated by using it to understand annealing temperature and surfactant choice and in terms of charge carrier dynamics in organic solar cells made from the P3HT:PCBM, PBTZT-stat-BDTT-8:PCBM, and PTB7:PCBM material systems.
关键词： charge carrier mobility,machine learning,organic solar cells,thin film solar cells,drift diffusion
更新于2025-09-12 10:27:22
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Interfacial crosslinked controlled thickness graphene oxide thin-films through dip-assisted layer-by-layer assembly means
摘要： The augmentation of research in graphene based thin films has been of great interest to various current industrial stakeholders. This is mainly due to the wide scope of films applications, ranging from nanoelectronics to separation membranes. Therefore, establishing a relation between graphene based thin film key characteristics and the fabrication operating conditions is of high significance. This study entails the successful fabrication of controlled-thickness crosslinked graphene oxide (GO) thin films on inexpensive silicon-based glass slide substrates. The method of film fabrication used is the dip-assisted layer-by-layer assembly, which has an added advantage of step-control of thin film thickness, good film uniformity and continuity. The thickness was primarily tuned through the use different sized crosslinkers; a covalent based sub-nanometer sized p-phenylenediamine and an electrostatic based polyethyleneimine on an interchangeable assembly with GO. Pre film fabrication, Fourier Transform Infra-Red and X-Ray Photoelectron Spectroscopy characterizations were carried out to determine the nature of interactions between GO and the crosslinkers. Post film fabrication, scanning electron microscopy, water contact angle measurements and profilometry analysis were undertaken for film continuity, hydrophilicity and thickness measurements respectively. A strong linear trend between film thickness of the differently crosslinked films and the number of bi-layers was established.
关键词： Graphene oxide,Thin film,Crosslinking,Thickness,Layer-by-layer
更新于2025-09-12 10:27:22
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Thermal regulation of photovoltaic panel installed in Upper Egyptian conditions in Qena
摘要： High ambient temperature and excessive solar radiation, especially in Upper Egypt, are essential factors in photovoltaic (PV) panel overheating, which in turn reduce its efficiency in such regions. Therefore, this study aims to develop a cooling system for the proposed thin-film PV panel installed in a harsh climate region in Qena City in Upper Egypt to obtain practically reasonable electrical efficiency. To achieve this target, three different cooling systems and operating modes were investigated: open-loop water-based cooling system, closed-loop water-based cooling system with free-convection air-cooled heat exchanger, and closed-loop water-based cooling system with forced-convection air-cooled heat exchanger using a DC fan. All these systems were supplemented with a fourth operating mode without cooling, i.e., normal conditions. The PV panel efficiency was experimentally investigated using the proposed cooling systems, and the experimental results demonstrated that without cooling, the daily average efficiency reached only approximately 6.2%, whereas it increased to 11.3% when the open-loop system was used. However, the daily average efficiency reached 8.5% using the closed-loop free-convection cooling system, and it reached 10.5% when the closed-loop forced-convection cooling system was used. Therefore, these cooling systems are highly recommended for application as effective techniques to increase the PV panel performance. The entire experimental data were obtained during a 10-h period from 7:00 a.m. to 5:00p.m.
关键词： PV panel,Electrical efficiency,Thin film,Free and forced convection
更新于2025-09-12 10:27:22