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Evidence and Influence of Copper Vacancies in p-Type CuGaO <sub/>2</sub> Mesoporous Films
摘要： Delafossite CuGaO2 nanocrystals were hydrothermally synthesized and characterized spectroscopically and electrochemically as mesoporous thin films. The nanocrystals demonstrate a preferred orientation within the film structure, as shown by enhancement of the (00l) peaks via two-dimensional powder X-ray diffraction. Annealing conditions of low and high temperature (i.e., 100?300 °C), with oxygen and/or argon atmospheres, were investigated, and the resulting effect on the thin film electrochemistry was measured. Cyclic voltammetry showed an increase in non-faradaic current with higher annealing temperatures and demonstrated a quasi-reversible redox feature (E1/2 = 0.1 V vs Fc+1/0). This feature is assigned to a CuII/CuI redox couple associated with surface defects. X-ray photoelectron and energy dispersive spectroscopies provide evidence for CuII surface defects and copper vacancies. Electrochemical impedance spectroscopy revealed that CuGaO2 films were highly conductive with σ ～ 10?5 Ω?1 cm?1, consistent with a large density of hole carriers induced by copper vacancies. The significance of synthesis, film preparation, and annealing conditions on the presence of surface defects and large hole densities is discussed. The prevalence of such defects in delafossite CuGaO2 is expected to have a large impact on the use of this material as a hole transport layer in solar cell architectures.
关键词： p-type metal oxide,delafossite,hole transport,heterojunction solar cell,CuGaO2
更新于2025-09-23 15:23:52
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Simulation of Silicon Heterojunction Solar Cells for High Efficiency with Lithium Fluoride Electron Carrier Selective Layer
摘要： In this work, to ameliorate the quantum e?ciency (QE), we made a valuable development by using wide band gap material, such as lithium ?uoride (LiFx), as an emitter that also helped us to achieve outstanding e?ciency with silicon heterojunction (SHJ) solar cells. Lithium ?uoride holds a capacity to achieve signi?cant power conversion e?ciency because of its dramatic improvement in electron extraction and injection, which was investigated using the AFORS-HET simulation. We used AFORS-HET to assess the restriction of numerous parameters which also provided an appropriate way to determine the role of diverse parameters in silicon solar cells. We manifested and preferred lithium ?uoride as an interfacial layer to diminish the series resistance as well as shunt leakage and it was also bene?cial for the optical properties of a cell. Due to the wide band gap and better surface passivation, the LiFx encouraged us to utilize it as the interfacial as well as the emitter layer. In addition, we used the built-in electric and band o?set to explore the consequence of work function in the LiFx as a carrier selective contact layer. We were able to achieve a maximum power conversion e?ciency (PEC) of 23.74%, ?ll factor (FF) of 82.12%, Jsc of 38.73 mA cm?2, and Voc of 741 mV by optimizing the work function and thickness of LiFx layer.
关键词： electric ?eld,silicon heterojunction solar cell,lithium ?uoride,electron selectivity contact layer,work function
更新于2025-09-23 15:21:01
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Enhancement of power conversion efficiency of Al/ZnO/p-Si/Al heterojunction solar cell by modifying morphology of ZnO nanostructure
摘要： This paper proposes a cost-effective sol–gel method for synthesis of ZnO nanostructure to make Al/ZnO/p-Si/Al heterojunction solar cell. Here, crystalline ZnO nanostructure was grown on p-silicon and annealed at 300 °C, 400 °C and 500 °C for application in heterojunction solar cell. The optimum temperature for obtaining uniform crystalline nanostructure was 500 °C, as confirmed from XRD and SEM imaging. As investigated by UV–Vis spectroscopy, the ZnO nanostructure layer exhibited high transmittance in the visible spectrum and has a direct band gap of 3.26–3.28 eV. The power conversion efficiency of Al/ZnO/p-Si/Al solar cell is enhanced from 1.06 to 2.22% due to increase in surface area of ZnO by formation of crystalline nanostructure due to increase of annealing temperature. The optimum value of short-circuit current (Isc) and open-circuit voltage (Voc) was measured using current–voltage (I–V) under AM 1.5 illuminations and found to be 9.97 mA and 460 mV, respectively.
关键词： Power conversion efficiency,Sol–gel method,Annealing temperature,Heterojunction solar cell,ZnO nanostructure
更新于2025-09-23 15:19:57
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Review of Rear Emitter Silicon Heterojunction Solar Cells
摘要： This inclusive study provides detailed information regarding the evolution of rear emitter silicon heterojunction solar cells. Silicon heterojunction (SHJ) solar cells of a p-type on the rear side have garnered increasing attention for various reasons. First, owing to a limitation of the p-type hydrogenated amorphous silicon layer, further optimization relative to an n-type cannot be achieved, and an accumulation of electrons at the front side allows utilizing an n-type wafer to affirm a lateral current transport. Second, better thin n-type nanocrystalline silicon (oxide) contact layers compared to p-type wafers are grown, and allow greater freedom in the structural design. The optical properties of the front side’s transparent conductive oxide (TCO) layer can be emphasized owing to a lateral transport on the cells, and majority of the carriers are affirmed through a Si substrate. In the instance of a rear emitter, the TCO layer is in relief to an adjustment inhibiting the contact resistance between TCO/a-Si:H(p). The fabrication was done in such a manner of SHJ rear emitter solar cells that they achieve greater optimization and overall efficiency of 23.46%.
关键词： Heterojunction solar cell,Lateral transport,Rear emitter,Transparent conductive oxide
更新于2025-09-19 17:13:59
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Effects of oxidation state on photovoltaic properties of reactively magnetron sputtered hole-selective WO<sub>x</sub> contacts in silicon heterojunction solar cells
摘要： The stoichiometry value x of WOx, or its oxidation state, is crucial for improving performances of the hole-selective contact heterojunction silicon solar cell. However, it is challenging to tune the films’ oxidation state using the well-known evaporation method. In this study, a simulation was performed to analyze the effect of x on short-circuit current (Jsc) loss, attributed to the hole-selective contact in the device. Compared to the thickness of WOx layer, x has a more important role in minimizing Jsc loss. Based on the simulation, the WOx/c-Si heterojunction solar cells having hole-selective WOx contacts with tuned x to vary its oxidation state were fabricated using reactive magnetron sputtering. The relationships of the open-circuit voltage (Voc) and Jsc with respect to x were similar. The experimentally determined Jsc increased from 34.7 to 36.6 mA/cm2 when x was increased from 2.72 to 2.77; this result is consistent with the simulation. Nevertheless, fill factor (FF) reduced with the increase of x, owing to the reduced conductivity of WOx. Both oxidation state and film conductivity must be as high as possible to simultaneously achieve high Voc, Jsc, and FF. The lowest x yielded a solar cell efficiency of 13.3%.
关键词： Current loss,Tungsten oxide,Hole-selective contact,Heterojunction solar cell
更新于2025-09-19 17:13:59
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Radiation hardness investigation of heterojunction solar cell structures with TCO antireflection films
摘要： Phosphorus doped silicon carbide film as emitter in heterojunction structure was deposited on p-type Si(100) wafers at various deposition conditions by means of PECVD technology using silane (SiH4), methane (CH4), hydrogen (H2) and phosphine (PH3, 2 vol.% in H2) gas as precursors. ITO or IZO film was RF magnetron sputtered on top of the different P doped a-SiC:H(n) film. Irradiation of structures with Xe ions to total fluency 5x1011 cm-2 was performed at room temperature. Influence of phosphorus concentration and type of transparent conducting oxide was investigated. A deeper insight on the impact of irradiation on the electrophysical properties of sample was obtained by the analysis of complex impedance spectra.
关键词： Xe ions irradiation,RF magnetron sputtering,TCO antireflection films,radiation hardness,impedance spectra,heterojunction solar cell,PECVD
更新于2025-09-19 17:13:59
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Charge transfer in Nanowire-Embedded PEDOT:PSS and Planar Heterojunction Solar Cells
摘要： Hybrid metallic nanowires-embedded, highly conductive poly(3,4-ethylenedioxy thiophene):polystyrenesulfonate (PEDOT:PSS) with synergetic properties is indispensable for enhancing the performances of conductive polymer-based electronic devices. Here we report embedment of silver nanowires (AgNWs), with diameter ~100 nm and a high concentration (500 mg/ml) of nanowires dispersed in either ethanol or isopropanol, in PEDOT:PSS and compare the effects of the nanowire-dispersing solvents as well as its thicker diameter and high concentration on the overall properties, and particularly its charge transfer characteristics and planar heterojunction solar cell (HSC) properties. Furthermore, electrostatic force microscopy is applied to elucidate the direct charge transfer from AgNWs to the PEDOT:PSS matrix. The AgNW-embedded PEDOT:PSS-based planar HSCs show a very high open-circuit voltage of over 638 mV and a high power conversion efficiency greater than 15.3%, and without any significant influence from the AgNWs dispersing solvents. While charge transfer in PEDOT:PSS without AgNWs occurs through the conducting PEDOT grains, enhanced charge transfer is realized in AgNW-embedded PEDOT:PSS with charge transport from PEDOT grains to AgNWs and then to PEDOT grains before reaching the top electrode in the HSC. The AgNW-embedded PEDOT:PSS hybrid materials pave a simple way to enhance the charge transfer performance in not only HSCs but also other hybrid or heterojunction electronics.
关键词： heterojunction solar cell,poly(3,4-ethylenedioxy thiophene):polystyrenesulfonate or PEDOT:PSS,silver nanowire,Conducting polymer,electrostatic force microscopy,charge transfer
更新于2025-09-19 17:13:59
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Cu 2 O Layer Analysis and Optimization Based on a Metal-Oxide Tandem Heterojunction Solar Cell
摘要： An analysis of Cu2O layer has been conducted for advanced thin film solar cells based on a tandem heterojunction design with metal oxides, in order to evaluate and improve the metal-oxide subcell performance. We have considered a promising cell design with metal oxide active and passive layers. We have used a comparative analysis based on numerical modeling in wxAMPS for device characteristics, with respect to the layer’s thickness and doping. It has been proved that the metal oxides hold great potential of optimization and have a big impact for the improvement of this design. The assessment has been made for the Cu2O/ZnO segment cell, as a basis, with the position of the defects in the middle of the band gap. The simulation methodology could be used for design and material performance optimization. The calculated values were compared with the experimental ones reported in the literature.
关键词： metal-oxide,heterojunction solar cell,cuprous oxide layer
更新于2025-09-16 10:30:52
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Improving carrier transport in strontium-doped cuprous oxide thin films prepared by Nebulizer spray pyrolysis for solar cell applications
摘要： Strontium-doped Cu2O thin ?lms of different doping concentrations (0, 3, 5 and 7%) are deposited successfully with the help of Nebulizer spray technique. All the samples were characterized by XRD, AFM, Raman, UV–Vis, photoluminescence and Hall effect, and solar cell ef?ciency is calculated. From the XRD studies, the cubic structural phase of Cu2O is con?rmed. The micrographs of AFM explain that the particles were uniformly distributed on the surface with homogeneous grains. The band gap value ranges from 2.17 to 1.95 eV as the doping concentration increases from 0 to 7%. The PL emission at * 630 nm also con?rms the cuprous oxide phase. The deposited ?lm exhibits p-type conductivity with low resistivity of 0.90 9 102 X cm and high carrier concentration of 22.7 9 1015 cm-3. A heterojunction solar cell of FTO/n-ZnO/p-Sr-doped Cu2O is fabricated, and the power conversion ef?ciency (g) is 0.75% for 7% Sr-doped ?lm.
关键词： Strontium-doped Cu2O,Resistivity and heterojunction solar cell,AFM,Optical studies,Raman
更新于2025-09-16 10:30:52
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Effect on the reduction of the barrier height in rear-emitter silicon heterojunction solar cells using Ar plasma-treated ITO film
摘要： In this study, we investigated the effect of plasma treatment on an indium tin oxide (ITO) film under an ambient Ar atmosphere. The sheet resistance of the plasma-treated ITO film at 250 W (37.6 ?/sq) was higher than that of the as-deposited ITO film (34 ?/sq). Plasma treatment was found to decrease the ITO grain size to 21.81 nm, in comparison with the as-deposited ITO (25.49 nm), which resulted in a decrease in the Hall mobility. The work function of the Ar-plasma-treated ITO (WFITO = 4.17 eV) was lower than that of the as-deposited ITO film (WFITO = 5.13 eV). This lower work function was attributed to vacancies that formed in the indium and oxygen vacancies in the bonding structure. Rear-emitter silicon heterojunction (SHJ) solar cells fabricated using the plasma-treated ITO film exhibited an open circuit voltage (VOC) of 734 mV, compared to SHJ cells fabricated using the as-deposited ITO film, which showed a VOC of 704 mV. The increase in VOC could be explained by the decrease in the work function, which is related to the reduction in the barrier height between the ITO and a-Si:H (n) of the rear-emitter SHJ solar cells. Furthermore, the performance of the plasma-treated ITO film was verified, with the front surface field layers, using an AFORS-HET simulation. The current density (JSC) and VOC increased to 39.44 mA/cm2 and 736.8 mV, respectively, while maintaining a WFITO of 3.8 eV. Meanwhile, the efficiency was 22.9% at VOC = 721.5 mV and JSC = 38.55 mA/cm2 for WFITO = 4.4 eV. However, an overall enhancement of 23.75% in the cell efficiency was achieved owing to the low work function value of the ITO film. Ar plasma treatment can be used in transparent conducting oxide applications to improve cell efficiency by controlling the barrier height.
关键词： Work function,Silicon heterojunction solar cell,Transparent conducting oxide,AFORS-HET,Plasma treatment,Indium Tin Oxide
更新于2025-09-16 10:30:52