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Tuning the electronic, optical and structural properties of GaS/C2N van der Waals heterostructure for photovoltaic application: first-principle calculations
摘要： Due to the increased energy demand, a large amount of renewable energy is required to sustain the lives of people. The visible light semiconductors for photovoltaic cells with optical properties and a tunable bandgap have been studied to bring the solution to energy crises. Two-dimensional (2D) semiconductors including gallium sulphide (GaS) and carbon nitride (C2N) monolayers as a photovoltaic material were investigated by designing GaS/C2N van der Waals (vdWs) heterostructure. In this study, density functional theory (DFT) was employed to study the structural, photovoltaic applications, electronic and optical properties of GaS/C2N vdWs heterostructure. In comparison with the counterparts of GaS and C2N monolayers, the GaS/C2N vdWs heterostructure showed a lower desirable direct bandgap of 1.251 eV and the projected density of states shows a type-I band alignment. The work function of the heterostructure is much lesser than the GaS monolayer and C2N layer, which signifies that less energy will be needed for electrons to transfer from the ground state. The charge density transfer shows charge redistribution from GaS to C2N. The power conversion efficiency (η) of GaS/C2N heterostructure is calculated to be 17.8%. Based on the results, the 2D GaS/C2N heterostructure is predicted to be effective material in developing a high-performance photovoltaic device for future use.
关键词： Density functional theory,Heterostructure,Power conversion efficiency,Photovoltaic cells
更新于2025-09-16 10:30:52
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Investigation of Rear-Emitter GaAs <sub/>0.75</sub> P <sub/>0.25</sub> Top Cells for Application to III–V/Si Tandem Photovoltaics
摘要： A rear-emitter (rear-junction) n-on-p+ device design was investigated for use in metamorphic monolithic III–V/Si tandem solar cells as an alternative to the traditional front-emitter (front-junction) n+-on-p design for potentially greater resistance to threading dislocation-induced performance degradation. A comparison of MOCVD-grown rear- versus front-emitter 1.7-eV bandgap GaAs0.75P0.25 top cell isotypes demonstrated as 30-mV advantage in WOC for the rear-emitter design. This reduction in WOC was determined to be nearly equally caused by a reduction in junction recombination current as well as reduced reverse saturation current from improved quasi-neutral region transport. These results suggest that the rear-emitter design may indeed be a promising pathway for application to metamorphic cells, including III–V/Si tandems, where achieving maximum voltage output is often hindered by elevated dislocation densities. However, further optimization of short-circuit current collection is needed to overcome suboptimal collection probability pro?les that could limit the ef?cacy of such structures.
关键词： semiconductor epitaxial layers,photovoltaic (PV),photovoltaic cells,III–V semiconductor materials
更新于2025-09-12 10:27:22
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Ester-substituted Pentathiophene Copolymer based Sky-blue Semitransparent Solar Cells for Building Windows
摘要： For oligothiophene-based donor polymers, the reports of pentathiophene are rare, while other oligothiophene (bi-, ter- and quaterthiophene) have been broadly studied. Here, we synthesized one wide-band-gap (1.88 eV) polymer PFTzTT-3TC, based on ester-substituted pentathiophene and benzotriazole. PFTzTT-3TC: ITIC (1.0:1.0) -based polymer photovoltaic cells exhibited best PCE of 8.21% and Voc of 0.90 V without additive (such as DIO, 1-CN) or post-treatment. These are the highest PCE and Voc for ester-substituted pentathiophene-based devices to date. Furthermore, semitransparent polymer photovoltaic cells with an active blend of PFTzTT-3TC: ITIC (1.0:1.0) demonstrate a similar Voc of 0.89V and a PCE of 6.43% with an AVT of 26.77% and an AT of 30.58% and CIE (0.25, 0.21). The sky-blue of semitransparent devices is useful for photosynthesis in plants and visual comfort in human and make it suitble for building windows.
关键词： benzotriazole,ester-substituted pentathiophene,organic photovoltaic,building windows,semitransparent polymer photovoltaic cells
更新于2025-09-12 10:27:22
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Can Thermodynamics Guide Us to Make Better Solar Cells?
摘要： Thermodynamics has provided a powerful tool to study radiation and its conversion into useful work. Starting from the so-called Shockley’s paradox, this article discusses the thermodynamic view of fundamental losses to photovoltaic conversion, and how thermodynamics enters the charge-carrier transport in semiconductors and heat-exchange processes at p-n junctions. Turning to photon flows, considerations based on detailed balance and reciprocity provide a comprehensive picture of the voltage produced by the solar cell in the presence of nonradiative recombination. We shall use these tools to examine several topics under recent discussion, including photon recycling and hot-carrier conversion based on thermoelectricity.
关键词： thermodynamics,thermoelectricity,solar energy,Photovoltaic cells
更新于2025-09-12 10:27:22
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Electron Versus Hole Extraction: Self Doping Induced Performance Bottleneck in Perovskite Solar Cells
摘要： Efficient and balanced collection of photo-generated charge carriers is a fundamental requirement for high efficiency solar cells – including perovskites. Any process or bias induced asymmetry in carrier collection leads to degradation in efficiency. Here, for the first time, we show that process induced self-doping in the perovskite active layer could result in asymmetric carrier collection. Accordingly, interface quality at the majority carrier collection layer becomes the performance limiting factor in perovskite solar cells. Through detailed numerical simulations we identify optimization schemes to overcome the ill-effects due to self-doping and interface recombination. Further, the insights on asymmetric carrier collection has interesting implications on regular vs. inverted geometry and long term stability of perovskite solar cells – which could be of broad interest to the community.
关键词： Semiconductor device modeling,photovoltaic cells.
更新于2025-09-12 10:27:22
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A new approach for parameter estimation of the single-diode model for photovoltaic cells/modules
摘要： Solar energy has become a popular renewable energy source, leading to wide use of photovoltaic (PV) cells/modules in energy production. For this reason, realistic modeling of PVs and determining the equivalent circuit parameters is of great importance in terms of planning and operation. Hence, in this study, an analytical model for identifying the single-diode equivalent circuit parameters; series resistance ( Rs ), shunt resistance ( Rp ), diode ideality factor ( a ), diode reverse-saturation current ( Io ), and photon current ( Ipv ) for PV cells/modules is developed without neglecting any term. In order to test the accuracy of the model, a number of PV modules from different manufacturers are taken into account and the results are compared with those obtained by using such analytical models given in the literature. Current-voltage (I-V ) characteristics of the PV modules, which are studied here, are also simulated by comparing with the experimental I-V curves provided by the manufacturers. Results show that the values of the parameters obtained for the PV modules are consistent with those extracted by using other analytical models. In addition, I-V curves created by using the obtained parameters are in full agreement with the experimental data. The curves also show a high degree of compatibility with the ones created by using the optimal parameters of the two-diode models given in the literature. Moreover, the proposed model provides a great advantage in estimating equivalent circuit parameters in terms of ease of use, requirements for input data, dependency on initial conditions as well as considering the parameters which are neglected in such methods given in the literature.
关键词： Photovoltaic cells/modules,single-diode model,mathematical modeling,parameter extraction
更新于2025-09-12 10:27:22
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Microcharacterization of Interface Oxide Layer on Laser-Structured Silicon Surfaces of Plated Ni–Cu Solar Cells
摘要： Light-induced plating on laser-structured passivation layer openings is an alternative method to silver screen printing for fabrication of the front-side metal grid on silicon solar cells. Fundamental contact properties, such as adhesion and contact resistance, are determined at the highly inhomogeneous interface of laser-structured silicon and plated nickel. Usage of laser structuring and plating holds the risk that an interfacial oxide layer is incorporated to the contact stack. It is shown within this article that both native and laser-induced oxide formation influence contact properties. Although, a native oxide layer does not impede metal deposition during plating, the dynamics of the layer formation is shown to be changed. It is known that interface oxides harm the contact resistance, and it is reported that postplating annealing decreases the contact resistance. In this article, the microstructural basis of the temperature-induced changes is examined. By transmission electron microscopy and energy dispersive X-ray spectroscopy, no temperature-induced modification of the interface microstructure, such as silicide formation or metal-induced crystallization of the amorphous surface, is observed. Results suggest that the decrease is attributed to a temperature-induced change of the electrical properties of the interface oxide. Considering reports that partially closed interface oxide layers are an inherent feature of laser-structured plated contacts, the results presented motivate reconsidering the objective of postplating annealing. The results indicate that the beneficial impact of silicide formation is overrated for the case of laser-structured plated contacts, whereas the temperature-induced modifications on residual interface oxide layers are neglected in the scientific discussions on the given contact stack.
关键词： silicidation,semiconductor-metal interfaces,Photovoltaic cells,semiconductor device reliability
更新于2025-09-12 10:27:22
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New organic molecular based on Bis-Dipolar Diphenylamino-EndcappedOligo Aryl Fluorene Application for organic solar cells
摘要： In this work, we report on the structural, optical and electronic properties of a series of D-π-A-π-D type bis-dipolar Diphenylamino-Endcappedoligoarylfluorenes, (OF(2)Ar-NPh(2)). These molecules are studied by means of quantum chemical calculations based on density functional theory (DFT) using B3LYP functional with 6-31G(d,p) for all atoms and all states (ground and excited ). The study of the geometrical parameters, ground state (p, n) showed that the structures of these molecules are planar. As a result, the electronic properties HOMOs, LUMOs, energy gaps, were determined from the fully optimized structures. The absorption of these molecules were calculated using (TD-DFT)-B3LYP/631G (d,p) method. This fundamental information is a valuable data in designing and making promising materials for optoelectronic applications.
关键词： Optoelectronic applications,DFT,Organic,Photovoltaic cells
更新于2025-09-12 10:27:22
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New organic materiel based on benzothiadiazole for Photovoltaic application Solar Cells
摘要： In this work, we have studied conjugated polymers based on benzothiadiazole. the quantum chemical calculations on the structure and electronic and optics properties using the density functional theory (DFT), for the ground- and excited-state properties, respectively, using CAM-B3LYP and the 6-31G(d, p) basis set. These results will be devoted to the influence of the substitution benzothiadiazole on the electronic and optoelectronic properties of the polymer. The highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) levels of these compounds were calculated and compared to LUMO of fullerenes,C60 [6,6]-phenyl- C61-butyric-acid methyl ester to estimate the effectiveness of these molecules as electron donors in bulk heterojunction (BHJ) small molecules-fullerene solar cells. The absorption energies have been obtained from TD-DFT calculations performed on the excited-state optimized S geometries. Finally, the theoretical results suggest that both the introduction of benzothiadiazole groups contribute significantly to the electronic and optoelectronic properties of the alternating donor–acceptor–donor conjugated systems studied.
关键词： Benzothiadiazole,BHJ,DFT,Optoelectronic properties,Photovoltaic cells
更新于2025-09-12 10:27:22
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High Open‐Circuit Voltage Organic Photovoltaics Fabricated Using an Alkylidene Fluorene Derivative as a Non‐fullerene Acceptor
摘要： Alkylidene ?uorene-based molecular acceptors, AF-T-INCN and AF-T8-INCN, are synthesized for use in non-fullerene organic photovoltaics. Both AF-T-INCN and AF-T8-INCN exhibited absorption region from 400 to 700 nm in their neat ?lm states. Highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels were found to be ?5.79/?3.80 eV for AF-T-INCN and ? 5.82/?3.79 eV for AT-T8-INCN, respectively. The organic solar cell devices fabricated with AF-T-INCN exhibited relatively low device performances with an open-circuit voltage (VOC) of 0.25 V, a short-circuit current density (JSC) 0.47 mA/cm2, a ?ll factor (FF) 29%, and power conversion ef?ciency (PCE) 0.03%, because of its strong aggregation in the blending condition. In contrast, AF-T8-INCN exhibited increased solubility and improved device performances with a high VOC of 1.24 V, a JSC 2.18 mA/cm2, a FF 28%, and PCE 0.76%.
关键词： Organic photovoltaic cells,Non-fullerene acceptor,Alkylidene ?uorene
更新于2025-09-12 10:27:22