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Silver nanowire (AgNW) transparent conducting electrodes can be prepared via a low‐cost process and deliver optoelectronic performance comparable to or even better than that of indium tin oxide (ITO). However, their integration into a real device is challenging, mainly because of the weak adhesion between AgNWs and the underlayer. Furthermore, when AgNWs replace ITO, a different material needs to be considered for the antireflection coating (ARC) of a thin‐film solar cell. A combination of AgNWs and Al2O3 is employed to replace both ITO and the MgF2 in a Cu(In,Ga)Se2 (CIGS) thin‐film solar cell. The quality of the contact between the AgNWs and CdS buffer is improved by introducing a chemical‐bath‐deposited welding layer, which improves the fill factor of the cell from 43.4% to 68.7%. Accordingly, the exposed surface of the CIGS thin‐film solar cell changes from ITO to CdS. Therefore, the commonly used MgF2 ARC is replaced with Al2O3, which is a better match in terms of the refractive index for AgNW‐based CIGS thin‐film solar cells. The adoption of the Al2O3 ARC increases the short‐circuit current density of the cell by 7.3%. In conclusion, a device structure of Al2O3/AgNW/CdS/CIGS/Mo is suggested for CIGS thin‐film solar cells. [ABSTRACT FROM AUTHOR]

A comprehensive study of a novel structure for In2S3 based CIGS solar cell has been observed. The effects of the absorber layer and temperature with various back surface field (BSF) layers (SnS/SnTe/MoTe2/GeTe) are analyzed with the SCAPS‐1D simulator. Performances of the ultrathin CIGS solar cell enhanced with the proposed structure of ZnO:Al/i‐ZnO/In2S3/CIGS/BSF/Mo and efficiency reached over 24% with 1000 nm CIGS absorber layer. The cell with SnS BSF layer has obtained 24.41% efficiency but shows less stability with temperature variation. On the other hand, the cell with MoTe2 BSF shows better stability at a higher temperature and reached an efficiency of 24.14%. Besides, the cell with SnTe BSF also suitable for ultrathin In2S3/CIGS, which results in an efficiency of 23.27%. However, the cell with GeTe BSF can give just over 18% efficiency, but it shows greater stability with temperature changes. This study highlights the potential of BSF layer in In2S3/CIGS solar cell enhancing the performance and stability of cells by reducing recombination losses. The incorporation of a 50 nm BSF layer allows further thinning of the absorber layer, reducing material consumption in the fabrication process without sacrificing overall efficiency. [ABSTRACT FROM AUTHOR]

The relation between the structure of the silver network electrodes and the properties of Cu(In,Ga)Se2 (CIGS) solar cells is systemically investigated. The Ag network electrode is deposited onto an Al:ZnO (AZO) thin film, employing a self‐forming cracked template. Precise control over the cracked template's structure is achieved through careful adjustment of temperature and humidity. The Ag network electrodes with different coverage areas and network densities are systemically applied to the CIGS solar cells. It is revealed that predominant fill factor (FF) is influenced by the figure of merit of transparent conducting electrodes, rather than sheet resistance, particularly when the coverage area falls within the range of 1.3–5%. Furthermore, a higher network density corresponds to an enhanced FF when the coverage areas of the Ag networks are similar. When utilizing a thinner AZO film, CIGS solar cells with a surface area of 1.0609 cm2 exhibit a notable performance improvement, with efficiency increasing from 10.48% to 11.63%. This enhancement is primarily attributed to the increase in FF from 45% to 65%. These findings underscore the considerable potential for reducing the thickness of the transparent conductive oxide (TCO) in CIGS modules with implications for practical applications in photovoltaic technology. [ABSTRACT FROM AUTHOR]

Integration of photovoltaics (PV) into the built environment (BIPV) and infrastructure (IIPV) is required to increase the installed capacity of PV worldwide, while still leaving sufficient area for other land uses. Although BIPV applications have proven to play a significant role in the energy transition, road integrated IIPV concepts are less developed and bring challenges in mechanical and electrical stability and safety that still need to be addressed. In this work, the feasibility of integrating thin‐film CIGS (Copper Indium Gallium Selenide) modules into road tiles is investigated. PV road stacks were produced by gluing CIGS laminates onto concrete tiles and covering them with epoxy and glass granulates to form impact‐ and anti‐skid layers. IV (current–voltage) characteristics show that, respectively, a thin and thick epoxy layer results in 2% and 6.6% relative loss in power conversion efficiency. Although a thin protective layer would be beneficial to the power conversion efficiency of road modules, raveling tests show increased risk for electrical failure when a thin top layer is used. Pull‐off tests showed that the weakest adhesive strength (0.8 N/mm2) is between the thin‐film laminate and concrete, offering sufficient adhesive strength to at least withstand light traffic loading. Raveling and wheel tracking tests show no mass loss and only minor deformation of the stack, respectively, indicating no real risk of raveling or rutting. Thermal cycling and damp heat exposure of the PV road tiles show that yellowing of the top layers can significantly reduce performance over longer periods of outdoor operation. Damp heat exposure after mechanical loading shows no indication of moisture ingress on any of the tested configurations, suggesting the proposed CIGS laminate stack is able to withstand light traffic loading. From the measurement results, it can be concluded that thin‐film CIGS modules are mechanically and electrically suitable for road integration. Power conversion efficiencies over 12% can be attained with this technology, indicating its potential for renewable energy generation in road infrastructure. Performance stability can especially benefit from alternative top layer materials that maintain high transparency over long lifetimes. Additionally, pilot tests are required to demonstrate the potential of the technology in a controlled outdoor environment. [ABSTRACT FROM AUTHOR]

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This study evaluates In2O3:W as a transparent back contact material in wide‐gap (bandgap range = 1.44–1.52 eV) (Ag,Cu)(In,Ga)Se2 (ACIGS) solar cells for potential application as a top cell in a tandem device. High silver concentrations and close‐stoichiometric absorber compositions result in a complete depletion of free charge carriers, allowing for decent electron collection, despite the low diffusion length. Remarkable efficiencies of 13.6% and 7.5% are reached using 1 μm‐ and 400 nm‐thick absorbers, respectively. At rear illumination (i.e., superstrate backwall), the best cell shows an efficiency of 8.7%. For each of the four analyzed samples, the short‐circuit current at rear illumination reaches at least 60% of the value at front illumination. Losses arise from recombination at the back contact and a too low drift/diffusion length. The parasitic absorption by the transparent electrodes for photon energies close to the bandgap of a potential Si bottom cell (1.1 eV) is close to 15%. Strategies to reduce this value and to further increase the efficiency are discussed. [ABSTRACT FROM AUTHOR]

Aluminum‐based chalcopyrite materials have attracted attention because of the wide controllability range of their material properties and potential for use in energy‐conversion devices. Herein, CuAlSe2‐based thin‐film growth and solar cell device properties are discussed. Ternary CuAlSe2 thin films are relatively unstable and decompose weeks after film growth, even when preserved in a dry box. However, alloying with elemental In led to significant improvements in stability. Cu(In,Al)Se2 (CIAS) solar cells yield better photovoltaic performance than CuInSe2 cells, although the effective range of Al concentration that can improve device performance is narrower than that of elemental Ga in Cu(In,Ga)Se2 (CIGS). A decrease in the alkali metal concentration in CIAS films with increasing Al concentration is observed, indicating that the formation energy of alkali‐metal substitutional defects on the Cu site is high, and/or Al‐related complex defects formed are kinetically stable and difficult to replace with alkali metals once they form. Although the direct observation of alkali metals in the bulk (grain interior) of chalcopyrite CuInSe2 and CIGS films has been difficult to date, this result can serve as indirect evidence of the presence of alkali metals in the bulk of CuInSe2 films. [ABSTRACT FROM AUTHOR]

Wide-gap Cu(In,Ga)Se2 (CIGS) solar cells exhibit a superior match to the solar spectrum, resulting in a higher ideal efficiency (Eff). However, in reality, their device Eff is lower than that of narrow-gap CIGS solar cells. This study aims to identify the factors that limit the performance enhancement of wide-gap CIGS solar cells, focusing on the characteristics of the buffer layer. The influence of the thickness and doping concentration of the CdS layer on the built-in electric field and interfacial recombination of the heterojunction has been investigated through simulation. The simulation results indicate that when the doping concentration of the CdS layer is lower than or similar to that of the CGS layer, decreasing the thickness of the CdS layer (e.g., 10 nm) is beneficial for improving device performance. However, if it is higher than that of the CGS layer, increasing the thickness of the CdS layer (e.g., 50 nm) is conducive to improving device performance. The thickness of the CdS layer that maximizes the Eff of the wide-gap CGS device should be approximately 50 nm, and its doping concentration should be higher than that of the CGS layer. This optimization can simultaneously enhance the built-in electric field of the heterojunction and minimize its interfacial recombination, thereby improving the open-circuit voltage and Eff of wide-gap CGS devices.

Purpose:This study aims to adapt and verify the psychometric properties of the Craving for Internet Gaming Scale (CIGS) in a Polish sample. Craving, although observed as significantly associated with Internet Gaming Disorder, is not currently included in its diagnostic criteria. This research addresses the need for scales to measure craving in this particular context. Methods: The research involved a sample of 575 participants. Psychometric analysis, including confirmatory factor analysis, was conducted to assess the CIGS’ reliability and validity. Additional scales, such as the Game Transfer Phenomena Scale, Motives for Online Gaming Questionnaire, and the Depression Anxiety Stress Scales, were used for concurrent validity analysis. Results: The study results demonstrate the excellent psychometric properties of the Polish adaptation of the CIGS. It showed high reliability in terms of internal consistency and provided evidence for construct validity. Furthermore, it exhibited a positive correlation with various scales associated with problematic video game use and gaming addiction, while also showing a moderate negative correlation with self-control. Conclusions: Our findings suggest that the CIGS retains its psychometric properties in different cultures, making it a valuable instrument for comprehending craving within the context of Internet gaming disorder. Future research should focus on the adaptation of the CIGS to various cultural settings and the exploration of potential intergroup differences. [ABSTRACT FROM AUTHOR]

This paper presents a high performing Cu(In1 − xGax)Se2 (CIGS) based solar cell that uses naturally abundant and non-toxic InP (indium phosphide) as an electron transport layer and CuI (copper iodide) as a hole transport layer. These materials, InP and CuI, are better replacements for toxic material based solar cells. The proposed structure comprises a glass substrate/n-ZnO (Zinc oxide)/n-InP/p-CIGS/p-CuI/metal electrode. A graded CIGS layer (i.e. varying energy band gap and electron affinity) is used in this structure for a better harvesting of broad spectrum of solar energy. The proposed PV cell is optimized for different band gap grading of CIGS layer to enhance the performance of the cell. For further optimization of the proposed cell, thickness, doping concentration, and defect density of different layers are varied. After optimization, the proposed cell shows a maximum power conversion efficiency of 30.50% (Voc = 0.8857 V, Jsc = 39.57 mA cm−2, FF = 87.05%) for 1100 nm thickness of the CIGS layer. The optimized device is further analyzed for various temperatures and resistances (series and shunt). All the simulations are done at room temperature (300 K) using SCAP-1D software. [ABSTRACT FROM AUTHOR]

Second-generation thin-film Cu(In, Ga)Se2 (CIGS) solar cells are a well-established photovoltaic technology with a record power conversion efficiency of 23.6%. However, their reliance on critical raw materials, such as In and Ga, requires new approaches to reduce the amount of critical raw materials employed. The micro-concentrator concept involves the combination of thin-film photovoltaic technology with concentrator photovoltaic technology. This approach reduces the size of the solar cell to the micrometer range and uses optical concentration to collect sunlight from a larger area, focusing it onto micro solar cells. This work is devoted to the development of a process for manufacturing pre-structured substrates with regular arrays of holes with 200 and 250 µm diameters inside a SiOx insulating matrix. Subsequently, a Cu–In–Ga precursor is deposited by sputtering, followed by photoresist lift-off and the application of a Cu–In–Ga thermal annealing at 500 °C to improve precursor quality and assess pre-structured substrate stability under elevated temperatures. Finally, a two-stage selenization process leads to the formation of CIGS absorber micro-dots. This study presents in detail the fabrication process and explores the feasibility of a bottom-up approach using pre-structured substrates, addressing challenges encountered during fabrication and providing insights for future improvements in CIGS absorber materials. [ABSTRACT FROM AUTHOR]

This contribution studies the effect of ordered vacancy compounds (OVCs) on the minority carrier collection in wide‐gap (Ag,Cu)(In,Ga)Se2 (ACIGS) solar cells. For this purpose, three samples with different ([Ag]+[Cu])/([In]+[Ga]) (I/III) values were processed: 1) a very off‐stoichiometric absorber (I/III = 0.31), consisting of isolated chalcopyrite patches embedded in a major OVC bulk phase, 2) a moderately off‐stoichiometric absorber (I/III = 0.77) with OVC patches at the front and back interfaces and 3) a close‐stoichiometric absorber (I/III = 0.94) with only very few, isolated OVC patches. For each of these samples, synchrotron‐based X‐ray fluorescence (XRF) was measured on a nanoscale (55 nm resolution), while simultaneously recording the X‐ray beam induced current (XBIC). The results, complemented by transmission electron microscopy and electron‐beam induced current analyses, clearly indicate that the presence of the OVC phase reduces the carrier collection and thus the short‐circuit current density of off‐stoichiometric wide‐gap ACIGS solar cells. [ABSTRACT FROM AUTHOR]

CIGS thin film solar cells have attracted extensive attention due to their high conversion efficiency (the highest conversion efficiency of 23.35%). The electrodeposition method is widely used to prepare CIGS thin films because of its simple process, fast deposition rate, low equipment cost and high material utilization rate. However, the aggregation of Ga, poor crystallinity and the interface recombination led the poor conversion efficiency of 17.3%. In this work, pulsed optic-thermal coupling process was employed to improve the film quality and device performance. With the pulsed optic-thermal coupling process, the surface temperature of film could rise to 550 ℃ in few seconds, which suppressed the prefer reactions between In-Se and Ga-Se. Large-grained CIGS thin films were prepared with fine grains at the back contact eliminated, which improved the crystallinity. The performance of CIGS thin film solar cells was also improved with a conversion efficiency of 9.14% being obtained with the optimized pulsed optic-thermal coupling process. [ABSTRACT FROM AUTHOR]

The stability of molybdenum (Mo) back contact and Cu (InxGa(1‐x)Se2(CIGS) absorber layers interfaces relevant for CIGS‐based solar cells was investigated using accelerated aging test, considering humidity and temperature daily variations as well as atmospheric pollution. Different configurations of sputtered Mo and co‐evaporated CIGS layers deposited on soda lime glass with or without ALD‐Al2O3 encapsulation were investigated. They were exposed for 14 days to 24 h‐cycles of temperature and humidity (25°C at 85% RH and 80°C at 30% RH) with and without solution of the pollutant salts (NaCl, Na2SO4, and (NH4)2SO4) deposited as drops on the sample to mimic marine, industrial, and rural atmospheric conditions, respectively. ALD‐Al2O3 encapsulation failed to protect the samples against the pollutants regardless of configuration. The evolution of the films was characterized by Raman spectroscopy, grazing incidence X‐ray diffraction, X‐ray photoelectron spectroscopy, scanning electron microscopy, and energy‐dispersive X‐ray spectroscopy. Unencapsulated Mo degraded forming a mixture of oxides (MoO2, MoO3, and Mo8O23). Unencapsulated CIGS on glass substrates was not altered, whereas dark spots were visible at the surface of Mo/CIGS configurations. Further characterization evidenced that even though the Mo layer was buried, its corrosion products were formed on top of CIGS. Mo corrosion products and copper selenide, Cu2‐xSe, were identified in dark spots. Their formation and evolution were further investigated by in situ Raman spectroscopy. A speculative mechanism explaining the interplay of molybdenum and CIGS layers during aging is proposed. In place of Mo oxides, detected on the open surface of bare Mo, soluble molybdates are expected in confined environment where alkalinity locally increases. The molybdate ions may then react with sodium ions accumulated at the grain boundaries of CIGS, forming Na2MoO4. The latter could form Na2Mo2O7 during drying because of pH decrease by atmospheric CO2 adsorption. High pH in confined zone, combined with relatively high temperature, is also believed to lixiviate gallium into soluble tetragallates [Ga (OH)4]2−, which could precipitate into Ga2O3 with pH decrease leaving Ga depleted Cu2‐xSe. [ABSTRACT FROM AUTHOR]

در این مطالعه، سلول خورشیدی CIGS با ساختارMo/CuIn0.7Ga0.3Se2(CIGS) /CdS/ZnO/Al-Doped ZnO توسط نرم افزار Atlas silvaco-TCAD شبیه‌سازی شد. ویژگی‌های فتوولتائیک سلول خورشیدی با استفاده از لایه‌های بافر CdS و ZnSe محاسبه و مقایسه شد. سپس ویژگی‌های فتوولتائیک با ضخامت‌های مختلف لایة بافر ZnSe مورد بررسی قرار گرفت. ضخامت 25 نانومتر به‌عنوان ضخامت بهینه انتخاب شد. پس از بهینه‌سازی ضخامت لایه ZnSe، ویژگی‌های فتوولتائیک سلول خورشیدی با تغییر اختلاف نوار هدایت (CBO) مورد ارزیابی قرار گرفت. بالاترین راندمان تبدیل سلول خورشیدی CIGS در محدوده از eV5/0- تا eV5/0+ برای CBO به‌دست آمد. در نهایت، به‌دلیل شفافیت نوری بالا، تحرک حامل بالا و خواص مکانیکی مناسب، گرافن با Al-doped ZnO (AZO) جایگزین شد. گرافن به‌صورت تک لایه و چند لایه به‌عنوان لایة اکسید رسانای شفاف (TCO) استفاده شد. شبیه‌سازی‌ها بیشترین بازده را برای ساختار سلول خورشیدی بر اساس single layer graphene Mo/CIGS/ZnSe/i-ZnO/ و پارامترهای فتوولتائیک mA/cm2 64/38=Jsc ، V 67/0Voc=، %33/79=FF و 71/20η= درصد پیش بینی کردند.

Herein, the transparent conducting oxide (TCO) characteristics of the window layer as a factor in the decrease of conversion efficiency from lab‐scale cells to modules are focused on. Then, an optical model and a circuit model are constructed based on measured data, and TCO parameters are investigated to optimize Cu(In,Ga)Se2 (CIGS) module characteristics. Simulations assuming ZnO:Al and ZnO:B as the TCO, which are commonly used in CIGS modules with a substrate structure, show that the range of the TCO parameters to obtain high efficiency is limited. In particular, the optimum values of module characteristics are separated into high‐carrier density/thin‐film region with a smooth surface and low‐carrier density/thick‐film region with a textured surface for the TCO layer. In addition, simulations assuming a high‐mobility TCO and a wide‐gap CIGS absorber to boost conversion efficiency reveal that the wide‐gap CIGS absorber mitigates the effects of resistance losses and free carrier absorption due to the TCO, thereby expanding the design range of the carrier density in the TCO layer. [ABSTRACT FROM AUTHOR]

The Cu (ln1‐xGax)Se2 (CIGS) solar cell technology is a potentially high‐efficient approach with unique properties compared with silicon photovoltaic, like flexible lightweight substrates and different colored designs. So far, the full potential of the transparent conductive oxide layers has not been exploited yet as no front contacts are applied, resulting in significant losses from the cell‐to‐module level. In this study, Ag front contacts are applied by parallel dispensing onto indium tin oxide layers of silicon heterojunction substrates and CIGS substrates. Subsequently, a thermally curing process is carried out to form the conductive contacts. The curing conditions are varied between 200°C ≥ Tc ≥ 100°C combined with 20 min ≥ tc ≥ 1.5 min. The study aims to determine the curing parameters enabling low‐resistivity contacts by using low‐temperature curing Ag paste and ultralow‐temperature curing Ag paste. The lateral electrode resistance and the contact resistivity of printed electrodes are measured. The results of simultaneous thermogravimetry‐differential scanning calorimetry (pastes) and microstructure analysis of printed electrodes are used to explain the electrical parameters of the printed electrodes. In general, higher curing temperatures and longer curing durations encourage the sintering and densification process of the applied electrodes resulting in low‐resistivity contacts. Contact resistivities below ρc,TLM < 5 mΩ·cm2 and lateral electrode resistance of Rlateral ≥ 17 Ω m−1 are obtained for different paste systems. However, optimal curing conditions of low‐temperature curing pastes can cause thermal damage to the CIGS device. Therefore, ultralow‐temperature curing pastes seem to be promising candidates for front contact metallization of CIGS substrates. [ABSTRACT FROM AUTHOR]

Small voids in the absorber layer of thin‐film solar cells are generally suspected to impair photovoltaic performance. They have been studied on Cu(In,Ga)Se2 cells with conventional laboratory techniques, albeit limited to surface characterization and often affected by sample‐preparation artifacts. Here, synchrotron imaging is performed on a fully operational as‐deposited solar cell containing a few tens of voids. By measuring operando current and X‐ray excited optical luminescence, the local electrical and optical performance in the proximity of the voids are estimated, and via ptychographic tomography, the depth in the absorber of the voids is quantified. Besides, the complex network of material‐deficit structures between the absorber and the top electrode is highlighted. Despite certain local impairments, the massive presence of voids in the absorber suggests they only have a limited detrimental impact on performance. [ABSTRACT FROM AUTHOR]

In this study, a CIGS solar cell with a Mo/Cu(In0.7Ga0.3)Se2(CIGS)/CdS/ZnO/Al-doped ZnO (AZO) structure was simulated by Atlas silvaco-TCAD software. The photovoltaic characteristics of solar cells using CdS and ZnSe buffer layers were calculated and compared. Then, the photovoltaic characteristics were examined with different thicknesses of the ZnSe buffer layer. The 25 nm thickness was selected as the optimum thickness. After optimization of the ZnSe layer thickness, the photovoltaic characteristics of solar cells were evaluated by changing the conduction band offset (CBO). The highest CIGS solar cell conversion efficiency was obtained in the range from -0.5 eV to +0.5 eV for CBO. Finally, graphene was replaced with Al-doped ZnO (AZO) due to its high optical transparency, high carrier mobility, and proper mechanical properties. Graphene was used as a monolayer and multilayer as a transparent conductive oxide (TCO) layer. Simulations predicted the highest efficiency for solar cell structure based on Mo/CIGS/ZnSe/i-ZnO/monolayer graphene and the photovoltaic parameters were Jsc=38.64 mA/cm², Voc=0.67 V, FF=79.33% and η=20.71%. [ABSTRACT FROM AUTHOR]

Photovoltaic installed cumulative capacity reached 849.5 GW worldwide at the end of 2021, and it is expected to rise to 5 TW by 2030. The sustainability of this massive deployment of photovoltaic modules is analysed in this article. A literature review, completed with our own research for emerging technologies has been carried out following life cycle assessment (LCA) methodology complying with ISO 14040 and ISO 14044 standards. Different impact categories have been analysed for five commercial photovoltaic technologies comprising more than 99% of current market (crystalline silicon ~94% and thin film ~6%) and a representative of an emerging technology (hybrid perovskite). By using data from LCA inventories, a quantitative result for 15 impact categories has been calculated at midpoint and then aggregated in four endpoint categories of damage following ReCiPe pathways (global warming potential, human health damage, ecosystems damage and resources depletion) in order to enable a comparison to other renewable, fossil fuel and nuclear electricity production. In all categories, solar electricity has much lower impacts than fossil fuel electricity. This information is complemented with an analysis of the production of minerals with data from the British Geological Survey; the ratio of world production to photovoltaic demand is calculated for 2019 and projected to 2030, thus quantifying the potential risks arising from silver scarcity for c‐Si technology, from tellurium for CdTe technology and from indium for CIGS and organic or hybrid emerging technologies. Mineral scarcity may pose some risk for CdTe and CIGS technologies, while c‐Si based technology is only affected by silver dependence that can be avoided with other metals replacement for electrodes. When the risks grow higher, investment in recycling should boost the recovery ratio of minerals and other components from PV module waste. [ABSTRACT FROM AUTHOR]

The bandgap widening of Ag-alloyed Cu(In,Ga)Se2 (ACIGS) thin films poses a significant challenge in enhancing their photocurrent. This study demonstrates correlations between element diffusion behavior and notch-point formation in ACIGS films, which ultimately influence the resulting current circuit voltage and fill factor. Our findings delineate a novel approach for fabricating a suitably tailored band gap grading in ACIGS, which serves as a bottom subcell in tandem configuration. This was achieved by modulating a wide range of process temperatures from 340 to 470 °C, which were measured by pyrothermal, to assess the GGI profile during deposition. Experiments were undertaken to variate the second-stage conditions, striving to sustain the photocurrent, mitigate defects, and enhance crystallinity, achieving an impressive performance of 17.7 % without applying post-deposition treatments or anti-reflection coatings. The efficiencies surpassing 8 % were achieved as we measured these cells under a 715 nm long-pass filter, which corresponds to the bandgap of a typical top cell in tandem applications (1.73 eV photon energy). These results emphasize the significance of understanding the deposition temperature and its impact on the properties of ACIGS films, paving the way for further advancements in solar-cell technology.

The photovoltaic performance of copper indium gallium diselenide (CIGS)-based solar cells with Cd-free single buffer layers and a barium disulfide (BaSi2) back-surface field (BSF) has been studied through a numerical approach using a one-dimensional solar cell capacitance simulator (SCAPS-1D). The efficacy of the buffer layer of cadmium sulfide (CdS) via FTO/CdS/CIGS/BaSi2/Mo heterostructure has been studied first and thereafter toxic CdS is replaced by various non-toxic buffers; zinc selenide (ZnSe), indium-doped zinc sulfide (ZnS:In), and indium sulfide (In2S3). Comprehensive research has been performed on the effects of buffer layer thickness, gallium (Ga) concentration in CIGS absorber, BaSi2 BSF doping density, various back contact metals, and cell operating temperature. The highest power conversion efficiency (PCE) of the CIGS-based solar cell with the CdS buffer layer is 26.24 percent, while solar cells with Zn-based buffers made of ZnS:In or ZnSe show improved PCE of 17.68 percent and 17.56 percent, respectively. This study demonstrates the enormous potential of Zn-based ZnS:In and ZnSe buffers for the experimental fabrication of high-efficiency thin-film solar cells with the following structure: FTO/buffer/CIGS/BaSi2/Mo.

Abstract Small voids in the absorber layer of thin‐film solar cells are generally suspected to impair photovoltaic performance. They have been studied on Cu(In,Ga)Se2 cells with conventional laboratory techniques, albeit limited to surface characterization and often affected by sample‐preparation artifacts. Here, synchrotron imaging is performed on a fully operational as‐deposited solar cell containing a few tens of voids. By measuring operando current and X‐ray excited optical luminescence, the local electrical and optical performance in the proximity of the voids are estimated, and via ptychographic tomography, the depth in the absorber of the voids is quantified. Besides, the complex network of material‐deficit structures between the absorber and the top electrode is highlighted. Despite certain local impairments, the massive presence of voids in the absorber suggests they only have a limited detrimental impact on performance.

Using a quaternary compound target, Cu(In,Ga)Se2 films are prepared using one‐step, selenization‐free direct current magneton sputtering (DcMS) and high power impulse magnetron sputtering (HiPIMS) methods. This study investigates how the sputtering power affects the composition, microstructure, morphology, and electrical characteristics of the films. Film crystallinity is found to be affected by the sputtering power utilized. The films deposited at 0.25 kW are amorphous, whereas those formed at 0.5–1 kW display a chalcopyrite structure with a (112)–preferred orientation. With increased sputtering power, the films' crystal quality improves, displaying a homogeneous and compact morphology free of peeling and cracking. Elemental measurement of the CIGS films reveals that, depending on the deposition method, the film composition deviates from that of the target. The electrical properties of the deposited films vary with increasing sputtering power. [ABSTRACT FROM AUTHOR]

Building-integrated photovoltaic technologies have considerable potential for the generation of onsite renewable energy. Despite this, their market penetration is in a relatively embryonic phase with respect to grounded or building-attached solutions, and they have limited commercial application. Their integration into building façades may represent a key asset in meeting the net-zero emissions by 2050 scenario, in particular for high-rise buildings in which the roof-to-façade ratio is unfavorable for the fulfillment of the energy load using only roof photovoltaic technology. Moreover, different façade orientations extend the production time throughout the day, flattening the power generation curve. Because of the present interest in BIPV systems, several researchers have conducted high-quality reviews focused on specific designs. In this work, various photovoltaic technologies and methods used to manufacture façade BIPV devices are reviewed with the aim of presenting researchers with the recent technological advancements and providing an overview of photovoltaic systems designed for different purposes and their applications rather than a detailed analysis of a specific technology. Lastly, future prospects and the limitations of building-integrated photovoltaic devices are presented. [ABSTRACT FROM AUTHOR]

Big sets of experimental data are key to assess statistical device performance and to distill underlying trends. This insight, in turn, can then be used to improve on the fabrication process. We here describe a standardized and optimized inline fabrication process and present a statistical analysis of tens of thousands of cells with chalcopyrite‐type Cu(In,Ga)Se2 absorber. The large number of samples allows us to point out where Ag alloying into the absorber offers improvements, and how it couples with compositional and optoelectronic properties. Solar cell parameters as a function of chemical composition of the absorber highlight the importance of fill factor on overall cell performance. Finally, we calculate losses in open‐circuit voltage as a function of band gap energy and show that radiative losses can be reduced by increasing the amount of Cu and/or Ag. [ABSTRACT FROM AUTHOR]

Two types of Cu(In,Ga)Se2 (CIGS) thin-film solar modules, differing only in the patterning procedures, were exposed to a high voltage (1 kV) across the thickness of the soda-lime glass substrate. Both module types utilized a cell stack, and in particular, a molybdenum back contact, which was optimized for CIGS solar cells with enhanced stability against potential-induced degradation (PID). A standard module with regular patterning lines for monolithic interconnection consists of P1, P2, and P3 lines, with P1 separating the back contact, P2 establishing the contact between the front contact TCO of one cell to the Mo back contact of the next cell, and P3 isolating the front contact from one cell to the next cell. However, modules employing this cell stack with regular patterning lines P1, P2, and P3 suffered considerably from PID while modules with a P1 groove filled with an insulator showed greatly enhanced stability similar to the pure single cell without P1 patterning. PID manifests once a specific quantity of charge has been transmitted through the soda-lime glass substrate, while the molybdenum back contact of the cell functions as the cathode, maintaining a negative bias relative to the substrate's backside. As a consequence of PID, sodium is increased in the adsorber for susceptible cells. Therefore, inhibiting sodium transport through the P1 groove by filling it with an insulating material enhances the PID stability of the modules considerably. As a result, the modules with a filled P1 groove showed similar stability to the single solar cells with an improved PID stable cell stack, while modules without a filled P1 patterning were much more susceptible to PID, although a cell stack with greatly enhanced PID stability was used. In summary, the presented strategy to fill the P1 groove offers a viable and novel path to improved PID stability of CIGS modules. [ABSTRACT FROM AUTHOR]

Thin-film solar cells have been referred to as second-generation solar photovoltaics (PV) or next-generation solutions for the renewable energy industry. The layer of absorber materials used to produce thin-film cells can vary in thickness, from nanometers to a few micrometers. This is much thinner than conventional solar cells. This review focuses on inorganic thin films and, therefore, hybrid inorganic–organic perovskite, organic solar cells, etc., are excluded from the discussion. Two main families of thin-film solar cells, i.e., silicon-based thin films (amorphous (a-Si) and micromorph silicon (a-Si/c-Si), and non-silicon-based thin films (cadmium telluride (CdTe) and copper–indium–gallium diselenide (CIGS)), are being deployed on a commercial scale. These commercial technologies, until a few years ago, had lower efficiency values compared to first-generation solar PV. In this regard, the concept of driving enhanced performance is to employ low/high-work-function metal compounds to form asymmetric electron and hole heterocontacts. Moreover, there are many emerging thin-film solar cells conceived to overcome the issue of using non-abundant metals such as indium (In), gallium (Ga), and tellurium (Te), which are components of the two commercial thin-film technologies, and therefore to reduce the cost-effectiveness of mass production. Among these emerging technologies are kesterite CZTSSE, intensively investigated as an alternative to CIGS, and Sb2(S,Se)3. In this review, after a general overview of the current scenario of PV, the three main challenges of inorganic thin-film solar cells, i.e., the availability of (safe) metals, power conversion efficiency (PCE), and long-term stability, are discussed. [ABSTRACT FROM AUTHOR]

• An ultra-thin film CIGS solar cell with a cluster back reflector can outperform single nanoparticles. • Optimizing plasmonic parameters can minimize light transmission in solar cells. • The results indicate an increase in short-circuit current density from 19 mA/cm 2 in the bare cell to 27.2 mA/cm 2. In this paper, an ultra-thin film CIGS solar cell using a cluster back reflector is discussed to improve optical parameters. This cluster nanostructure includes four silver nanoparticles embedded in the back surface of the active layer. By optimizing the effective parameters of the plasmonic phenomenon, such as length, width, height, and distances between the nanoparticles, among the studied cases, the cylindrical nanostructure, is selected as the most efficient back reflector. To achieve these results, it is mainly focused on short-circuit current density analysis. Besides, power conversion efficiency, absorption spectrum and transmission of light are also studied. As a result, due to the localized surface plasmon resonance enhancement, short-circuit current density and power conversion efficiency reach 27.2 mA/cm2 and 15.7 %, respectively. These values for the bare state were 19 mA/cm2 and 10.7 %. [ABSTRACT FROM AUTHOR]

Cu(In,Ga)(S,Se)2 (CIGSSe) solar cells are one of the most promising thin film photovoltaics with a record efficiency of 23.6%. However, the biggest drawback to CIGSSe solar cells is their high material cost, partially resulting from relatively rare and expensive indium and gallium. Therefore, improving the utilization of indium and gallium and reducing their wastage can greatly lower the cost of CIGSSe thin film solar cells. Inkjet printing is a facile, cost‐effective, and low‐waste deposition technology, which is particularly suitable for low‐cost and large‐area fabrication of CIGSSe solar cells. Herein, a novel and green ionic liquid‐assisted ink to fabricate highly efficient CIGSSe solar cells is developed. The material utilization of inkjet printing can be remarkably improved compared to the conventional vacuum‐based deposition approach and spin‐coating solution approach. The CIGS printable ink is prepared by dissolving copper acetate, indium acetate, gallium nitrate, and thiourea into ethanol with the assistance of n‐butylammonium butyrate ionic liquid. Ionic liquid‐assisted CIGS ink has a nearly zero wetting angle and a tunable viscosity, which enable to deposit a flat and continuous CIGS thin film by an inkjet printing method. An encouraging power conversion efficiency of 15.22% has been achieved for inkjet‐printed CIGSSe solar cells. [ABSTRACT FROM AUTHOR]

Thin film solar cells are leading the charge toward a greener future, offering a renewable energy source that can be scaled up to meet the rising demand for clean energy. Copper-indium-gallium-selenium (CIGS) is a promising material for solar cells due to its excellent absorption coefficient, affordability, and non-toxic nature. As per the literature, CdS is the most commonly used buffer layer for CIGS solar cells, which is toxic. Therefore, in this article, a CIGS-based solar cell is proposed using In2S3 as a buffer layer. The efficiency achieved by this In2S3 -based CIGS solar cell is 17.7%. To further enhance the efficiency, this work utilizes the most exciting property of CIGS—their tuneable bandgap. A bandgap that can be adjusted is known as a tuneable bandgap, which can be achieved by altering the composition of the CIGS material. In this context, the bandgap of CIGS is modified by gradually changing the semiconductor's composition throughout its thickness. Thus, in this work, linear grading, parabolic grading and beta-grading profiles are used to obtain the optimum composition for the CIGS layer. Grading of CIGS helps to reduce transmission and thermalization losses by optimizing the cell's ability to absorb a wide range of wavelengths of light and by tailoring the energy bandgap of the material. Another critical factor for obtaining the highest efficiency is the thickness of the absorber layer. Therefore, the thickness of the CIGS layer was also varied along with the grading profiles. The results show that maximum efficiency of 25.2% can be achieved using beta grading. Additionally, the results show that the optimum CIGS layer thickness is 1 µm for CIGS-based solar cells. [ABSTRACT FROM AUTHOR]

Reverse breakdown in Cu(In,Ga)Se2 (CIGS) solar cells can lead to defect creation and performance degradation. We present pulsed reverse-bias experiments, where we stress CIGS solar cells with a short reverse voltage pulse of ten milliseconds and detect the electrical and thermal response of the cell. This way, we limit the duration of the reverse stress, allowing us to study the initial stages of reverse-bias defect creation in CIGS solar cells and modules. Our results show that permanent damage can develop very fast in under milliseconds. Furthermore, we find the location of defect creation as well as the susceptibility to defect creation under reverse bias depends strongly on whether the cell is encapsulated or not, where encapsulated cells are generally more robust against reverse bias.

Second-generation thin-film Cu(In, Ga)Se2 (CIGS) solar cells are a well-established photovoltaic technology with a record power conversion efficiency of 23.6%. However, their reliance on critical raw materials, such as In and Ga, requires new approaches to reduce the amount of critical raw materials employed. The micro-concentrator concept involves the combination of thin-film photovoltaic technology with concentrator photovoltaic technology. This approach reduces the size of the solar cell to the micrometer range and uses optical concentration to collect sunlight from a larger area, focusing it onto micro solar cells. This work is devoted to the development of a process for manufacturing pre-structured substrates with regular arrays of holes with 200 and 250 µm diameters inside a SiOx insulating matrix. Subsequently, a Cu–In–Ga precursor is deposited by sputtering, followed by photoresist lift-off and the application of a Cu–In–Ga thermal annealing at 500 °C to improve precursor quality and assess pre-structured substrate stability under elevated temperatures. Finally, a two-stage selenization process leads to the formation of CIGS absorber micro-dots. This study presents in detail the fabrication process and explores the feasibility of a bottom-up approach using pre-structured substrates, addressing challenges encountered during fabrication and providing insights for future improvements in CIGS absorber materials.

An all-inorganic lead-free tandem PV cell consisting of two sub-cells CsSn0.5Ge0.5I3 (perovskite) based top cell/CIGS-based bottom cell has been designed, simulated, and optimized by varying the thickness of pertinent layers utilizing the SCAPS-1D simulator. In the top sub-cell, a wide bandgap lead-free inorganic CsSn0.5Ge0.5I3 perovskite is inserted as the primary absorber layer because of its distinctive characteristics with an ETL of ZnO, which is recognized for its high electron mobility & absorption coefficient, and an HTL of NiO to offer increased hole mobility with good chemical-durability. For the bottom sub-cell, we have selected p-type CIGS as the absorber with Spiro-OMeTAD as the apposite HTL to provide suitable offsets of valence and conduction band distribution and TiO2 as ETL to offer low-cost, low-ecotoxicity, excellent optical properties, and chemical-stability and thus offers improved efficiency of the overall tandem structure. In the beginning, the two sub-cells were simulated independently; the top sub-cell was simulated under the standard spectrum of AM1.5G, while the bottom sub-cell was optimized using a filtered spectrum. Thereafter, the current matching point of both cells was attained by optimizing the absorber layer thicknesses. Finally, our computational modeling and simulation results offer the optimized cell structure revealing an outstanding overall 38.39% power conversion efficiency (PCE), Fill Factor (FF) of 83.4%, open-circuit voltage (VOC) of 2.48 V, and short-circuit current density (Jsc) of 18.64 mA cm−2. The proposed tandem structure's performance matrices outperform those stated in the most recent literature. These outcomes of the proposed structure are expected to facilitate the development and production of a low-cost and highly effective inorganic perovskite Tandem PV cell in the future.

This paper aims to investigate the photovoltaic performance of copper indium gallium selenide (CIGS) solar cells using SCAPS-1D (Solar Cell Capacitance Simulator in One Dimension) software. The novelty in this research revolves around applying lamellar tin sulfide (SnS2) as a buffer layer and tin monosulfide (SnS) as a back surface field (BSF) layer, which is noteworthy since few materials have previously been exploited in CIGS solar cell research. The studied solar cell is composed of four layers with different physical parameters: two p-type doped layers, SnS as the BSF layer and the CIGS as the absorption layer, as well as two other n-type doped layers, SnS2 as the buffer layer and aluminium-doped zinc oxide (AZO) as the window layer. This work covered the role and effect of the BSF (SnS) layer on the photovoltaic parameters of the CIGS solar cell device. In addition, the variation of thickness, acceptor concentration, band gap and operating temperature of the SnS layer was also optimized and analysed. Adding the BSF (SnS) layer between the absorber layer (CIGS) and the metal back contact (molybdenum [Mo]) leads to increased hole tunnelling activity, resulting in a quasi-ohmic contact of the Schottky type near the back surface. Thus, this contact improves the electric field region generated at the back interface. Also, reducing back surface recombination increases energy conversion efficiency. As a result, the inclusion of a 40 nm thin film of BSF layer at the optimum temperature of 300 K significantly enhanced the device's open-circuit voltage (VOC) from 0.73 V to 0.87 V, current density (JSC) from 36 mA/cm2 to 40 mA/cm2, fill factor (FF) from 84% to 86%, and power conversion efficiency (PCE) from about of 22% to 30%, for an absorption layer thickness of 1 μm. These findings offer great promise for the efficiency and economic viability of CIGS solar cells in the future. [ABSTRACT FROM AUTHOR]

This study evaluates the effect of silver alloying, stoichiometry, and deposition temperature of wide‐gap (Ag,Cu)GaSe2 (ACGS) absorber films for solar cell applications. Devices using a standard CdS buffer exhibit a strong anticorrelation between the open‐circuit voltage (VOC) and short‐circuit current density (JSC), with VOC decreasing and JSC increasing toward stoichiometric absorber composition. Increasing the ACGS deposition temperature leads to larger grains and improved JSC, while VOC is not affected. By adding more silver to the absorber (maximum tested [Ag]/([Ag]+[Cu]) [AAC] = 0.4), the widening of the space charge region (SCR) significantly enhances carrier collection. Experimental quantum efficiency spectra can be accurately simulated when assuming a very low diffusion length and perfect collection in the SCR. The highest efficiency of 8.3% (without antireflection coating [ARC]) is reached for an absorber with AAC = 0.4 grown at 600 °C. Replacing CdS by a (Zn,Sn)O buffer with lower electron affinity strongly mitigates interface recombination. Moreover, the VOC–JSC anticorrelation is not evident anymore and the highest efficiency of 11.2% (11.6% w/ARC, VOC = 985 mV, JSC = 18.6 mA cm−2, fill factor = 61.0%) is reached for a close‐stoichiometric ACGS solar cell with AAC = 0.4 processed at 650 °C. [ABSTRACT FROM AUTHOR]

This work proposes a new modeling framework based on combining graded band-gap (GBG) engineering and metaheuristic optimization to improve the Cd-Free ZnMgO/CIGS solar cell performances. Analytical and numerical calculations are carried out to assess the influence of band-gap profiles of both buffer and active layers on the electronic and optical properties of the studied solar cell. This investigation shows a great improvement of solar cell efficiency by increasing the optoelectronic figures of merit through tuning and optimizing the band-gap profiles and the conduction band offset at the ZnMgO/CIGS interface. Moreover, metaheuristic-based optimization models are developed to optimize the GBG profiles and enhance the optical and electrical performances of the solar cell. In this context, we recorded very satisfactory results, where the optimized design with GBG paradigm offers a high efficiency of 31.88% compared to 23.35% provided by the conventional CdS/CIGS solar cell. Therefore, this study provides a new strategy in enhancing the efficiency of thin-film solar cells by exploiting the graded band-gap engineering combined with metaheuristic optimization approach. [ABSTRACT FROM AUTHOR]

Reverse breakdown in Cu(In,Ga)S e 2 (CIGS) solar cells can lead to defect creation and performance degradation. We present pulsed reverse-bias experiments, where we stress CIGS solar cells with a short reverse voltage pulse of ten milliseconds and detect the electrical and thermal response of the cell. This way, we limit the duration of the reverse stress, allowing us to study the initial stages of reverse-bias defect creation in CIGS solar cells and modules. Our results show that permanent damage can develop very fast in under milliseconds. Furthermore, we find the location of defect creation as well as the susceptibility to defect creation under reverse bias depends strongly on whether the cell is encapsulated or not, where encapsulated cells are generally more robust against reverse bias. [ABSTRACT FROM AUTHOR]