The CIGSe-based thin film solar cells (TFSCs) are one of the most promising candidates in the photovoltaic market for harnessing solar energy into electrical energy due to their potential to achieve high efficiency-to-cost value. This review paper initially introduces the various types of photovoltaic technologies, which are classified depending on the types of materials used in photovoltaic devices. The complete information about the existing structure of CIGSe TFSCs is also described. The role of various materials used in CIGSe-based TFSCs, such as types and nature of substrates, back contacts, CIGSe-based absorber materials, window layers, and front contacts on the variation of the device’s performance is briefly explained. Moreover, this review paper defines the solar cell band structure and the recombination mechanisms found in the CIGSe solar cells. The effect of the alkali element doping in CIGSe absorber materials and the most used synthesis techniques for CIGSe-based thin films are effectively highlighted in this paper. This research work primarily focused on the current advancements found in the CIGSe-based TFSCs. The summary of research work, challenges, and future prospects of CIGSe-based TFSCs are also discussed. This information can be helpful in promoting the CIGSe TFSC from the laboratory to a commercial scale in the near future.

In this work, a 2D simulator (i.e., SILVACO ATLAS simulator) was used for modeling the Cu2ZnSn(S, Se)4 (CZTSSe) thin film solar cells. This simulation study mainly focused on the influence of the electrical and optical parameters that describe the electrical properties of each layer and the absorbed radiation in the heterostructure. These two parameters are analyzed and optimized to get as high of an efficiency as possible. It was characterized by means of the simulation that the effect of the electrical and optical parameters on the solar cell output parameters (VOC,JSC,FF,andη) was studied. The other parameters, such as temperature, bandgap, mobility, and thickness, were also varied in this simulative study for optimizing the device performance. The second record efficiency of 12.6% was observed for the CZTSSe thin film solar cell (TFSC). This obtained result was compared with the results attained from the SCAPS-1D simulation as well as the second record efficiency for CZTSSe TFSC. Moreover, the Haze function was used to characterize the transmittance and diffuse reflectance in the rough interfaces between the layers of the solar cell. The Haze function utilized the input data like roughness and correction prefactors, which mainly impact the root-mean-square interface roughness (σrms) value by studying the External Quantum Efficiency curve variation. After analyzing these parameters, the efficiency was slightly improved to 13.02%. Therefore, theoretical modeling could be beneficial to design highly efficient devices without utilizing experimental resources.

This study focuses on the synthesis of a CaO-ZnFe 2 O 4 composite derived from waste materials such as eggshell CaO and ZnFe 2 O 4 via a combustion process using orange peel as fuel. The composite was prepared by mechanical milling, sonication in ethanol, and annealing. Structural, morphological, and surface characterizations were carried out using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and Brunauer-Emmett- Teller (BET) analysis, which confirmed the successful formation of the composite. The material was shown to be highly effective in removing malachite green dye through adsorption studies, demonstrating a significant capacity for dye removal. Kinetic modeling based on the pseudo-second-order equation indicated that the adsorption process was driven by chemisorption. In addition, the adsorption process was found to be endothermic, as the removal of malachite green increased with increasing solution temperature.

In this simulation study, the SCAPS software is used to analyze the Cu(In, Ga)Se2 (CIGSe) thin film solar cells. The parameters, such as thickness, bandgap, and carrier concentration of CIGSe absorber layer, V 2 O 5 buffer window layer and ZnO window layer are investigated to obtain the best device performance. The efficiency of CIGSe thin film solar cells is slightly enhanced by absorbing more photons when the CIGSe thickness increases from 1 to 6µm. The variation of CIGSe bandgap affects all four solar cell parameters, which is directly related to the energy of incident photons. The open circuit voltage and fill factor are dependent on the CIGSe carrier concentration. The optimum values of 3µm, 1.4 eV, and 10 16 cm -3 were thickness, bandgap, and carrier concentrations for CIGSe. A very thick layer of window layers can raise the series resistance and a very thin layer can reduce the shunt resistance of the device. Both of these conditions strongly decreased the fill factor and consecutively the efficiency value. The best thicknesses of 100 and 25 nm were observed for V 2 O 5 and ZnO materials, respectively. The carrier concentrations for the window layer must be higher compared to the absorber layer for improving the device's performance. The optimum efficiency of 14.58 % is found for CIGSe thin film solar cells after using the best parameters of CIGSe, V 2 O 5 , and ZnO. Hence, the SCAPS software is promising for modeling and is imperative to assess the proposed physical structure's practicability and performance.

This study evaluates the adsorption efficiency of dyes (methylene blue, malachite green, and Rhodamine B) on charcoal and activated charcoal under controlled conditions. Significant variations in adsorption were observed which can be attributed to the molecular structure of the dye and the surface properties of the adsorbent. Malachite green showed the highest adsorption on inactivated charcoal, followed by methylene blue and Rhodamine B. Activation of charcoal increased the adsorption capacity for all dyes, especially for methylene blue and Rhodamine B, due to the introduction of oxygenated functional groups. Kinetic studies showed that the adsorption conformed to the pseudo-second-order model. The results suggest that activated charcoal is a promising material for dye removal, especially for those with lower initial affinities.

The thermal oxidation of evaporated titanium-vanadium thin films was carried out at different post-annealing temperatures. The structural, morphological, compositional, optical, electrical, and gas sensing properties of titanium-vanadium oxide thin films were primarily investigated. The results of the XRD study and Raman spectroscopy verified the presence of the orthorhombic V2O5, tetragonal TiO2, and monoclinic V2Ti3O9 phases. The crystallinity of TVO thin films was improved at higher annealing temperatures. The grain size (seen from SEM images) and oxygen compositions (obtained from EDS measurement) of TVO samples are also enhanced when the post-annealing temperature is increased from 500 to 575 degrees C. From the transmittance curves, the bandgap values for TVO samples were estimated and found in the range of 2.14-2.36 eV. The n-type conductivity of TVO films was confirmed by the negative Hall coefficient values. At last, the CO gas sensing response of TVO thin films was analyzed by monitoring the change in the surface electrical resistances at different operating temperatures and CO gas concentrations. The dynamic and static resistances were assessed at different operating temperatures varying from 100 to 300 degrees C. The TVO sample prepared at 550 degrees C showed the best conditions by examining the materials and CO sensing properties.

In this study, BiVO4 particles were synthesized via the combustion method using orange peel powder as a fuel for photocatalytic methylene blue (MB) degradation. The novelty lies in using biomass as a fuel source and leveraging orange peel phytochemicals as stabilizing and complexing agents, eliminating the need for nitric acid required in conventional methods. XRD patterns showed that the orange peel promotes ternary phase formation (Dreyerite and Clinobisvanite phases), while urea supports the binary and ternary phase combination (i.e., V6O13 and BiVO4). Raman, XPS, and FTIR analyses confirmed the BiVO4 monoclinic phase formation using both fuels, with a band gap of approximately 2.4 eV. Increasing annealing temperature reduced structural disorder, V–O bond length, and surface area, which are more pronounced with orange peel. Photocatalytic experiments revealed the significant MB removal by adsorption with urea, while orange peel primarily drove photocatalysis in both cases, following a pseudo-first-order kinetic model. Scavenger experiments showed holes as the main reactive species promoting MB degradation. With a rise in catalyst dosage, removal is primarily enhanced through adsorption, confirmed by dark condition experiments. The BiVO4 sample annealed at 350 ºC with orange peel fuel exhibited the best photocatalytic performance that can completely remove MB after 270 min under 200 W LED light.

Mechanosynthesis, particularly through high-energy ball milling, offers a potent method for the fabrication of nanohybrids. This study explores the characterization of TiO 2 and graphene oxide (GO) nanohybrids, focusing on their optical and electrical properties, as well as their photocatalytic performance. Optical measurements showed a reduction in the bandgap from ≈3.27 eV in pristine TiO 2 to ≈3.02 eV in milled TiO 2 , while electrical conductivity increased from 5.59 × 10 -9 to 2.48 × 10 -8 S/cm. Despite these improvements, the addition of GO did not significantly impact the bandgap or electrical properties of the nanohybrids. Photocatalytic experiments using methylene blue (MB) under visible light irradiation demonstrated a dye degradation of ≈30-32% in all hybrid samples, indicating consistent photocatalytic activity regardless of GO oxidation degrees.

The copper indium selenium/copper indium gallium selenium (CI(G)Se)-based thin film solar cells (TFSCs) have been fascinating in the photovoltaic market due to their potential to attain high efficiency of solar cells and modules at relatively little cost. This research work introduces the simulation of the CI(G)Se TFSCs through SCAPS software. Some parameters like thickness, bandgap, and carrier concentration of semiconducting materials used in the CI(G)Se TFSCs were optimized to get the solar cell efficiency as high as possible. The optimized efficiencies for CISe, CIGSe, and CIGSe bilayer TFSCs were 22.81, 27.32, and 27.99%, respectively. It is seen from the results that the device's performance using two absorber layers in CI(G)Se TFSCs was comparatively higher than using a single absorber layer. This outcome is mainly due to the better absorption of photons in CI(G)Se TFSCs containing two absorber layers. The SCAPS software also analyzed the experimentally obtained parameters of CI(G)Se and CdS thin films and noticed more than 20% efficiency, showing potential parameters to use in commercial applications. The effect of defects found in the CI(G)Se absorber layer, CdS buffer layer, and CdS/CI (G)Se interface on the solar cell parameters are primarily studied here. It is observed that the increasing defects in the CI(G)Se TFSCs could impact negatively the device's performance by recombining the generated charge carriers. Better results were found for CI(G)Se TFSCs at a lower work temperature (by reducing the saturation current, and at a smaller series resistance value as well as a larger shunt resistance value (by reducing the alternative paths for generated charge carriers). Therefore, understanding these results could provide complete information on the optimization process that can serve as a guide to achieve highly efficient electronic devices experimentally.

In this study are presented Cu 2 O thin films by microwave-assisted chemical bath deposition. The effect of temperature and time is studied on the film's structural, optical, and electrical properties. It was found that conductivity presents an opposite behavior when increasing time deposition at 65 and 70 ºC, promoting a decrease for films deposited at 65 ºC and an increase for films deposited at 70 ºC. This opposite behavior is correlated with structural defects (Urbach Energy), since these are reduced during the deposit carried out at 65 ºC and increase during the process carried out at 70 ºC. This can be explained by the fact that in the process at 65 ºC, the growth of the film thickness is continuous, that is, it increases more or less uniformly all the time, causing an increase in the crystallite and in the particles observed in SEM with a more or less well-defined morphology. While in the case of films at 70 ºC, the thickness growth after 30 minutes of deposit is minimal, which generates changes in the structure of the deposited film, for example, a deterioration in the morphology of the particles is observed, these changes encourage an increase in structural disorder as well as a decrease in crystallite size.

In this study, the gold and gold-silver (Au-Ag) core-shell nanoparticles were synthesized via chemical reduction method at different types and quantities of precursor materials. Initially, the gold nanoparticles were prepared with different reducing agents (i.e., sodium borohydride, sodium citrate, and ascorbic acid) and their composites. The optical absorbance, morphology, and size distribution of gold nanoparticles were analyzed to observe the best deposition conditions, used for the Au-Ag core-shell synthesis. Then, the Au-Ag core-shell nanoparticles were grown at four different quantities (i.e., 175 mu L, 200 mu L, 225 mu L, and 250 mu L) of silver nitrate precursor to study their effects on the fluorescence property. Optical absorbance, transmission electron microscopy, and laser scanning confocal microscopy were used to characterize the as-synthesized Au-Ag core-shell nanoparticles. From the results of optical absorbance, a single peak is seen for gold nanoparticles while two peaks (major and minor peaks) are observed for Au-Ag core-shell nanoparticles. The sizes of gold and core-shell particles observed from TEM measurement are less than 10 nm, which is typically used in fluorescence applications. The CoSh-2 sample showed a better fluorescence property compared to other core-shell samples. With a rise in exposure time in a laser with a specific wavelength of 405 nm, the intensity of fluorescence declined more for the filter having shorter wavelengths than larger wavelengths. Analyzing these results can be useful to understand the perspective applications of Au-Ag core-shell nanoparticles like synthetic fluorophores application.

Graphene oxides (GOs), synthesized with different oxidation degrees and associated with Titanium dioxide (TiO2) nanoparticles show efficient adsorption processes for dye molecules in solution. The structural, morphology, electronic and optical features of the nanocomposites were investigated by dedicated methods. Water remediation was investigated through the adsorption efficiency of methylene blue (MB) dye as a function of the nanocomposites concentration from 1 to 5 g/L in solutions. While pristine TiO2 showed a maximum removal of similar to 44%, the incorporation of the GO ensures the fast and complete elimination of MB within 9 min. The ball milling process contributed to the increase in the number of defects and surface area in the nano-composites, which was demonstrated by ID/IG ratios by Raman spectroscopy and surface areas by BET. Pseudosecond-order and mechanistic kinetic models were considered, and the performed analysis points out the relevance of the pseudo-second-order model to account for the adsorption kinetics. The Langmuir and Freundlich isotherm models were applied to the experimental data to find an adequate model to describe the adsorption equilibrium, as well as the intra-particle diffusion model during the different adsorption stages involved in the TiO2/GO nanocomposites. The role of the oxidation degree of GO was clarified through their respective efficiency in the removal of the dyes.

In this study, the synthesis of Calcium–Magnesium oxide through the ball milling method using eggshell as a CaO source, developing an ecological process synthesis, is presented. After ball milling, an annealing process was carried out in order to increase the crystallinity of the material to enhance its optoelectronic properties by varying the temperature from 450 to 900 °C. The samples were analyzed by X-ray diffraction, Raman and UV–Vis spectroscopy, FE-SEM, photoluminescence, and BET analysis. The ball milling process itself promoted a reduction in particle size, which increased slightly during the annealing process, achieving a more homogeneous size distribution and improving its crystallinity, according to XRD and Raman spectroscopy. The samples were tested for the photodegradation of methylene blue (100 mL of a 10 ppm solution), using LED lamps (200 W). The best photodegradation performance was recorded with the sample annealed at 750 °C, which is explained by the more homogeneous size distribution and the greater surface area, a smaller band gap, and fewer surface defects, which causes greater absorption of light, a better transport of the charge carriers and consequently a better performance in the photodegradation of MB. The complete removal of MB was achieved in 20 min under sunlight stimulation, which can be reduced to 12 min using 400 mg of the catalyst . On the other hand, the trapping experiment showed that superoxide radicals ( · O 2 − ) and holes (h + ) are the key reactive species in the photodegradation process of MB. The kinetic study showed to follow a pseudo-first-order for all cases. These photodegradation results reported for the first time are better than those reported in other Calcium–Magnesium oxide synthesized by combustion or ultrasound-assisted methods.

In this study, the vanadium oxide powders were ball-milled at different milling times. The basic characterization for analyzing the properties of vanadium oxide samples and their sensing properties for carbon oxide were mainly studied. XRD results confirmed the formation of the orthorhombic crystal structure of V 2 O 5 by comparing the presence of peaks. Three dominant peaks, such as (001), (110), and (400), are found for both with and without ball-milled vanadium oxide samples. The crystallite sizes for vanadium oxide are varying from 12 to 20 nm. From the Raman spectra, the peaks at wavenumbers at around 142, 196, 287, 407, 524, 690, and 995 cm -1 are also related to the orthorhombic crystal structure of V 2 O 5 . The nanoclusters with irregular morphologies are seen from the SEM images. The compositions of vanadium atoms enhance with a rise in milling times. Symmetrical compositions of vanadium and oxygen atoms are observed for vanadium oxide powder milled at 9 hours. High absorption spectra are found for light having a wavelength ranging from 300 to 500 nm. The bandgaps of vanadium oxide samples are calculated using reflection spectra through the Kubelka-Munk theory. The bandgap values of vanadium oxide samples after ball milling are lower (i.e., less than 2.9 eV) than without ball milling. The sensing response of the ball-milled VO samples against a carbon monoxide gas are determined by analyzing the electrical resistances.

CIGSe thin film solar cells have been fascinating in the photovoltaic field due to their potential to get high conversion efficiencies at an attractive cost. The properties of the materials used in solar cells must be optimized to improve the efficiency. Here, SCAPS is utilized to simulate the CIGSe thin film solar cells. First, the material properties (i.e., thickness, bandgap, carrier concentration) of CIGSe, CdS, ZnO, and ZnO:Al are analyzed for the optimization process. The optimized efficiency of 27.32% is achieved for the CIGSe thin film solar cell. Then the effect of defect density and carrier capture cross section in CIGSe, CdS, and CdS/CIGSe interface on the performance of CIGSe thin film solar cell is reviewed. It is found that the higher the defects in the device lower the device’s performance. This decrement in the efficiency is due to the decrease in the diffusion length of charge carriers by enhancing the recombination centers for them, preventing the collection of charge carriers, and finally degrading the device performance. This theoretical study can guide as a roadmap to enhance solar cell performance experimentally.

The bandgap of two-dimensional graphene (G), graphene oxide (GO), and reduced graphene oxide (rGO) ma-terials is modified by the gradual incorporation and removal of functional groups on the surface of the material. In this work, using Density Functional Theory (DFT) with BIOVIA Materials Studio software, the variation of the bandgap of GO and rGO as a function of the O/C ratio has been studied. The direct relationship between the bandgap and the number of epoxide functional groups in the GO is demonstrated. A gradual increase in the bandgap from 0.211 to 3.58 eV was observed by varying the O/C ratio from 0.06 to 0.50. In the range of O/C ratios from 0.17 to 0.28, the bandgap decreased, estimating the lowest value of 0.0211 eV at O/C = 0.22 despite the increased functional groups in the material. This phenomenon is explained by the balance between the number of sp2 conducting states and the loss of linearity of the sheets due to the incorporation of functional groups. On the other hand, the GOs were reduced by gradually removing their functional groups at different O/C ratios, ranging from 0.50 to the total elimination of the epoxide functional groups. This study showed that the bandgap of the now-called rGOs varies according to two parameters: (i) the number of functional groups to be eliminated in a GO (reduction process) and (ii) the number of functional groups present in the GO to be reduced. This theoretical study has calculated the existence of multiple bandgaps in these materials, finding the most significant difference in the O/C ratio=0.33, estimating bandgaps of 0.50 eV and 1.82 eV, for rGO and GO, respectively, thus raising the need to be more specific in their denomination. Finally, the use of a nomenclature based on subscripts a, b, c, and d, describing the number of layers, the type of functional group, the number of functional groups added (in GO), and the number of functional groups removed in rGO, respectively, has been proposed.

In this work, density functional theory (DFT) calculations were used to investigate the effect of graphene (G) and graphene oxide (GO) on the electronic properties of TiO 2 . Initially, a bandgap of 3.23 eV was determined for pure anatase TiO 2 layers. Subsequently, with the incorporation of G and GO, a possible hybridization effect of the electron states at the interface was observed, leading to the formation of new intermediate energy bands not originally found in TiO 2 . This condition causes the bandgap of the hybrid material to be reduced. Our calculations further showed how both structures interact with the TiO 2 surface, providing valuable information that offers opportunities to optimize the interfaces and improve the performance of these materials in various applications.

This research work focused on the optimization of CI(G)Se thin films using the hybrid deposition method and the simulation of the CIGSe bilayer thin film solar cell (TFSC) by SCAPS-1D. The chalcopyrite crystal structure with the preferential orientation of (112), the slightly Cu-poor and Se-rich compositions, the compact and larger grains with irregular shapes, and the p-type conductivity of CI(G)Se was observed. From simulative results, the solar cell parameters are slightly affected by varying the material properties of the CISe. The thickness of 5 mu m, the carrier concentration of 1017 cm-3, and the bandgap of 1.4 eV are the optimized conditions for CIGSe. With an increase in the CdS thickness up to 100 nm, the efficiency is slightly increased. At a higher carrier concentration of CdS, the collection of generated charge carriers is enhanced by extending the space charge region towards the absorber layer. There are not found any variation in the solar cell parameters after analyzing the material properties of the ZnO window layer and ZnO:Al transparent conducting oxide. The optimized efficiency of 27.99% is noted after analyzing the material properties of each material used in the CIGSe bilayer TFSC. The experimental results of CI(G)Se and CdS thin films are also simulated in SCAPS-1D software and observed a slightly lower efficiency of 24.63%. This result showed that experimentally optimized parameters can have the potential to achieve more than 20% efficiency. Therefore, a brief analysis of the experimental and theoretical results could be helpful for designing experimental activities in the future.