P-type NiOx films are widely used as hole-transport layers (HTLs) in p–i–n perovskite solar cells (PSCs) owing to their wide bandgap, stability, and optical transmittance. Chemical bath deposition (CBD) is an effective method for growing metal oxide HTLs. However, NiOx films prepared by the CBD method have pinholes because of their small grain size, which makes it difficult to cover the substrate in all directions, leading to severe carrier recombination at the interface between NiOx and perovskite. Herein, the device efficiency is improved from 18.13% to 22.51% using NiOx prepared by CBD with seed-assisted growth and Cu-ion doping as the HTL. The addition of crystal seeds significantly enhances the grain size, resulting in better substrate coverage by the prepared NiOx films. Cu-ion doping improves the conductivity of the film and enhances its ability to extract holes. In addition, the results confirm that this method is suitable for the manufacturing of large-area modules and has good reproducibility. This research demonstrates an effective CBD method for creating NiOx films for use in PSCs and offers a new approach for preparing inorganic HTLs using CBD.

A fast and extensive build-up of green hydrogen production is a crucial element for the global energy transition. The availability of low-cost renewable energy at high operating hours of the electrolyzer is a central criterion in today's choice of location for green hydrogen production. It is analyzed how decreasing electrolyzer costs that are expected by many may influence this choice. The energy system optimization framework ESTRAM is used to find the optimum configuration of wind turbine, photovoltaic (PV), and electrolyzer capacity for covering a given hydrogen demand by locally produced green hydrogen in different European locations. It is found that PV is part of the cost-optimal solution in 96% of 1372 statistical regions in Europe. Decreasing electrolyzer costs are favoring the utilization of PV in wind–solar hybrid plants. At low electrolyzer costs, pure solar hydrogen outperforms the hybrid variant in many places if hydrogen storage is available, even with few full operating hours per year. At the same time, production costs are converging significantly. The article adds a new perspective to the discussion, as it is systematically shown how further technology development may lead to a shift in locational advantages for green hydrogen production, what should be considered to avoid stranded assets when building infrastructure.

The antimony selenide thin film solar cells technology becomes promising due to its excellent anisotropic charge transport and brilliant light absorption capability. Especially, the device performance heavily relies on the vertically oriented Sb2Se3 grain to promote photoexcited carrier transport. However, crystalline orientation control has been a major issue in Sb2Se3 thin film solar cells. Herein, a new strategy has been developed to tailor the crystal growth of Sb2Se3 ribbons perpendicular to the substrate by using the structural heterostructured CdS buffer layer. The heterostructured CdS buffer layer is formed by a dual layer of CdS nanorods and nanoparticles. The hexagonal CdS nanorods passivated by a thin cubic CdS nanoparticle layer can promote [211] and [221] directional growth of Sb2Se3 ribbons using a close space sublimation approach. The improved buffer/absorber interface, reduced interface defects, and recombination loss contribute to the improved device efficiency of 7.16%. This new structural heterostructured CdS buffer layer can regulate Sb2Se3 nanoribbons crystal growth and pave the way to further improve the low-dimensional chalcogenide thin film solar cell efficiency.

The power conversion efficiency (PCE) of organic–inorganic halide perovskite solar cells (PSCs) has increased rapidly in recent years, with the certified best perovskite single-junction photovoltaics reaching an astounding PCE of 26%. Formamidine (FA)-based perovskites possess excellent photovoltaic properties and superior thermal stability, establishing them as one of the most promising perovskite materials for light absorption. However, the issue of the phase instability of black-phase formamidinium lead iodide (α-FAPbI3) perovskite has seriously impeded its commercialization process, with the strain found in perovskite films being regarded as a significant factor impacting the stability of PSCs. This article begins by examining the sources of strain and the characterization techniques related to perovskites. Subsequently, it outlines the effects of strain on FA-based perovskites and presents strategies to modify lattice strain. Finally, the potential for strain engineering in the future is discussed. This review aims to clarify the impact of strain on FA-based perovskite, determine potential methods of strain engineering to enhance device performance, and ultimately facilitate the commercialization of these materials.

The adoption of photovoltaic (PV) modules for clean electricity relies on accurate measurements of their performance, which are essential for estimating their energy production potential. We discuss the calibration chain of PV cells and modules, with particular emphasis on primary reference cell calibrations. We present the direct sunlight method our group has developed for these calibrations and discuss critical improvements and upgrades that lead to calibration uncertainty as low as 0.45%. The ultimate motivation behind this work is to provide low-uncertainty performance measurements of PV modules, and lowering the calibration uncertainty of primary reference cells is a key first step toward achieving this goal. As the use of solar electricity continues to grow, the demand for primary reference cell calibrations will inevitably increase beyond what the small handful of primary calibration laboratories can provide today. Therefore, this work can serve as a useful guide for implementing primary PV reference cell calibrations using the outdoor method, as well as outlining the critical elements required to make these calibrations highly accurate.

Compared to polymer-based organic solar cells, all-small-molecule organic solar cells (ASM-OSCs) have garnered significant attention due to their well-defined chemical structures, lower batch-to-batch variation, straightforward synthesis and purification procedures, and easy to modulate properties. Recent developments in small molecule donors have enabled ASM-OSCs to achieve power conversion efficiencies in excess of 17%, gradually approaching those of polymer-based devices, and demonstrating considerable potential for commercialization. However, structural and morphological features in the all-small-molecule blend films, including crystallization behavior, phase separation, and molecular arrangement, play a crucial role in the photoelectric performance. This review systematically introduces and discusses recent advancements in ASM-OSCs in terms of design strategies for novel small molecule donors and device engineering. Additionally, the correlation between active layer morphology and structure and device performance is analyzed. Finally, the challenges and prospects of ASM-OSCs are discussed.

The current silicon heterojunction (SHJ) cells utilize indium-based transparent conductive oxide (TCO) layers for supporting the lateral carrier transport. However, In is a typical rare metal and its consumption in solar cell manufacturing must be minimized for sustainable production. In this work, the possibility to realize high-efficiency TCO-free SHJ cells, in which no In-based material is needed, is examined. It is found that monofacial rear-junction structure is beneficial to collect minority carriers efficiently without the help of TCO layers, regardless of the wafer polarity. In addition, the contact resistivity of locally metallized area must be minimized for efficient carrier transport. Based on these findings, a TCO-free SHJ cell showing an efficiency of 22.1%, which is comparable to that of the benchmark SHJ cell with TCO layers, is demonstrated. However, direct metallization of amorphous silicon layers causes the degradation in the photovoltaic property after prolonged annealing, probably due to the metal diffusion into Si. This degradation can be avoided by inserting a thin barrier layer such as a SnO2 layer. It is indicated in these results that it is possible to realize TCO-free SHJ cells with high initial efficiencies, and the main obstacle is not the efficiency but the long-term stability.

The emerging solar interfacial evaporation (SIE) technology is an effective measure to address freshwater resources. An efficient and stable solar interfacial evaporator cannot be achieved without the synergy of three key factors: water transport, solar thermal conversion and thermal management. The performance of a solar interfacial evaporator can be improved through the rational selection of materials and the structural design of these three key factors. Due to superior nanostructures, electrospun nanofibrous materials often exhibit some unique properties that facilitate the construction of solar interface evaporators with good performance. So far, electrospinning has been used to prepare structures such as solar absorbers, water transportation and thermal insulation in various solar interfacial evaporators. This review presents the fundamental research and technological development in the application of electrospinning techniques to solar interfacial evaporators on structures, morphology and properties. Then we summary the latest advances in the use of electrospinning technology in solar interfacial evaporators and present the current issues facing the application of electrospinning technology to solar interfacial evaporators. These systematic discussions can provide ideas and approaches for the rational design of electrospun nanofiber materials for solar interfacial evaporators in the future.

Interfacial solar desalination is widely regarded as a very promising strategy to alleviate global water shortages. In practical application, salting out, poor stability, short service life, complex structure preparation technology, and high cost are always the problems that people intend to solve. Here, a photothermal conversion film with hydrophilic and hydrophobic double-layer structure is prepared by a simple brush coating process. Among them, the top is used with hydrophobic acetylene black as a photothermal material, and the bottom is used with hydrophilic melamine foam as a carrier. The evaporation rate of the photothermal conversion film can reach 1.6 kg m−2 h−1 during continuous testing at a solar coefficient. At the same time, the photothermal conversion film has a very long service life and can still work after 24 days of continuous testing. A portable desalination device with the photothermal conversion film is designed and the average evaporation rate of water can reach 1.28 kg m−2 h−1 under an average solar illumination of 0.51 kw m−2 in outdoor environments.

Transparent conductive oxides that contain indium are widely used in various applications including solar cells. However, In is regarded as one of the critical and economically volatile elements, hindering its massive use in production. Herein, the possibility of using amorphous (a-)SnO2 transparent conductive oxides (TCOs) instead of In2O3-based TCOs in silicon heterojunction (SHJ) solar cells is explored. Reactive plasma deposition is utilized to fabricate a-SnO2 thin films suitable for solar cells, demonstrating good electrical conductivity (>1 × 103 S cm−1) and high damp heat stability while maintaining high transparency in the visible and near-infrared regions. Furthermore, the a-SnO2 film exhibits a larger optical bandgap than a-In2O3-based TCOs. When the a-SnO2 layer is applied to SHJ solar cells, it is found that the TCO layer shows almost no negative effect on fill factor, open-circuit voltage, and short-circuit current density compared to solar cells with indium tin oxide layers. In-free rear-junction SHJ solar cells with a-SnO2 on both sides of the wafer show an efficiency of 22.2%, suggesting the potential of a-SnO2 as a cost-effective and sustainable substitute for conventional In2O3-based TCOs used in solar cells and other applications.

Passivating contacts are crucial for realizing high-performance crystalline silicon solar cells. Herein, contact formation by plasma-enhanced chemical vapor deposition (PECVD) followed by an annealing step is focused on. Poly-SiOx passivating contacts by combining plasma-assisted N2O-based oxidation of silicon (PANO-SiOx) with a thin film of phosphorus (n+) or boron (p+)-doped hydrogenated amorphous silicon oxide (a-SiOx:H) are manufactured. Postannealing is conducted for transitioning a-SiOx:H into poly-SiOx. The aim is to achieve a contact with low absorption and high-quality passivation. It is demonstrated that by tuning the plasma oxidation process time and power, the PANO-SiOx thickness and its passivation quality can be controlled. A higher SiO2 content is observed in PANO-SiOx than in the nitric acid oxidation of silicon (NAOS-SiOx) counterpart. PANO-SiOx acts as a stronger diffusion barrier for both boron and phosphorus atoms compared to NAOS-SiOx, affecting the dopant distribution during annealing. Implied open-circuit voltages up to 751 and 710 mV for n+ and p+ flat symmetric samples, respectively, are demonstrated. With respect to standard thermally grown SiO2 tunneling oxide combined with (in/ex )situ-doped low-pressure chemical vapor deposition poly-Si, this study presents a simple alternative for manufacturing passivating contact fully based on PECVD processes.

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.

Photovoltaic systems may underperform expectations for several reasons, including inaccurate initial estimates, suboptimal operations and maintenance, or component degradation. Accurate assessment of these loss factors aids in addressing root causes of underperformance and in realizing accurate expectations and models. The performance loss rate (PLR) is a commonly cited high-level metric for the change in system output over time, but there is no precise, standard definition. Herein, an annualized definition of PLR that is inclusive of all loss factors and that can capture nonlinear changes to performance over time is proposed. The importance of distinguishing between recoverable and nonrecoverable losses which underly PLR is highlighted.

Metal halide perovskite photovoltaic performance required for commercial technology encompasses both efficiency and stability. Advances in both these parameters have recently been reported; however, these strategies are often difficult to directly compare due to differences in perovskite composition, device architecture, fabrication methods, and accelerated stressors applied in stability tests. In particular, it is found that there is a distinct lack of elevated temperature, operational (light and bias) stability data. Furthermore, significant testing is required to understand the interactions when combinations are used (e.g., additives used with posttreatments). Herein, individual and combined additive, posttreatment, and contact layer strategies from recent literature reports under standardized operational stability tests of p–i–n CsMAFA perovskites at 70 °C are evaluated. Through analysis of over 1000 devices, it is concluded that the hole-transport layer (HTL) is the most significant component impacting elevated temperature operational stability. This analysis motivates future development of high-performance HTLs.

The solution-processed electrode is key to the full-solution-processed organic solar cells (OSCs). Silver nanowires (AgNWs) are considered as an attractive solution-processed electrode due to their low sheet resistance and high transmittance. However, the traditional “line-plane” contact between AgNWs and the interface buffer layer is insufficient, resulting in the low performance of full-solution-processed OSCs. Herein, a bulk contact structure is reported between AgNWs and interface, formed by inserting the interface layer material, such as HMoOx (hydrogen molybdenum bronze) into the AgNWs networks. The extra HMoOx can be connected with the bottom interface buffer layer, forming a longitudinal network, and wrapping the AgNWs in the longitudinal interfacial layer. This bulk contact electrode-interface structure increases the area of AgNWs/interface layers, promoting charge transfer and collection. Besides, the top-injected method can enable the formation of a water-based ink film on the top of the organic layer, as well as avoid solvent erosion between AgNWs and the interface layer. Based on the bulk contact electrode-interface structure, this work realized high performance of 12.27% and 9.54% for 0.09 cm2 small-area device and 10.8 cm2 full-solution-processed semitransparent mini-module. These results provide a new idea for full-solution-processed OSCs preparation.

Microplastics (MPs) are regarded as a pervasive contaminant that poses threats to the environment and human safety. However, the high energy storage potential of the C–C and C–H bonds in MPs has led to increased attention toward technological methods for upgrading plastic waste to high-value-added fuels. Aqueous photocatalysis has emerged as a promising approach for upgrading MPs due to its solar-driven properties and ability to generate various radicals. While extensive investigations and reviews have been conducted on photocatalysts and the resulting products within this system, there is an emerging need to comprehensively understand the entire process to enhance efficiency and selectivity further. In this review, significant advancements in the overall system are summarized, including reactants, pretreatments, photocatalysts, additives, and reactors, to enable efficient and selective reactions based upon the principles of state-of-the-art photocatalytic microplastic upgrading. Furthermore, the shortcomings are clarified with proposed possible breakthrough points in each research direction. Ultimately, the significance of developments in pretreatments is highlighted, paving the way for future research possibilities.

Semitransparent perovskite solar cells (ST-PSCs) are highly promising for application in building-integrating photovoltaics (BIPVs) due to their potential in tunable transparency and color. However, the comprehensive performance of ST-PSCs falls quite short of the ideal requirements for BIPV. Herein, more attention is to review how to balance transparency and power conversion efficiency for ST-PSCs. Optimizing transparent electrodes and the active layers are interesting strategies to achieve the transparency required by devices. In addition, to obtain color ST-PSCs, tuning the bandgap of perovskite layers and designing the optical structure of the electrode are effective strategies. Last but not least, three significant optical evaluation indexes of ST-PSCs are described in the supporting information: average visible transmittance, color rendering index, and light utilization efficiency.

The effective defect passivation of metal halide perovskite (MHP) surfaces is a key strategy to simultaneously tackle MHP solar cell performances enhancement and their stability under operative conditions. Plasma-based dry processing is an established methodology for the modification of materials surfaces as it does not present the disadvantages often associated with wet treatments. This is becoming a fine tool to reach precise atomic-scale engineering of the MHP surfaces. Herein is reported a comprehensive picture of the interaction between different plasma chemistries and MHP thin films. The impact of Ar, H2, N2, and O2 low-pressure plasmas on MHP optochemical properties and morphology is correlated with the performance of photovoltaic devices and rationalized by density functional theory calculations. Strong morphological modifications and selective removal of the uppermost methylammonium moieties are deemed responsible for nonradiative surface defects suppression and higher solar cell performances. Ellipsometry and X-ray photoelectron spectroscopies shine light on the subtle modifications induced by the different plasma environments, paving the way for the more effective engineering of plasma-based (deposition) processing. Notably, for O2 plasma treatment, deep-state traps induced by the formation of IO4− species are demonstrated and rationalized, highlighting the challenges in optimizing O2 plasma-based solutions for MHP-based devices.

Perovskite Solar Cells

The native AlOx grown on a thin sputtered aluminum layer can be used as mask for electroplating copper, e.g., for metallizing silicon heterojunction (SHJ) solar cells. Effects that influence the masking quality for selective electroplating are studied herein. Atomic force microscopy characterization in PeakForce mode highlights the presence of some insulation defects in the native AlOx due to local contamination, pinholes, or tunneling currents. A focused ion beam/scanning electron microscopy analysis is further conducted to understand some defects in detail. The AlOx insulation can be improved by adsorbing a self-assembled monolayer, which is mainly required along the process sequence to adjust the surface wetting of the Al for optimal NaOHaq printing. The mask quality and complete metallization sequence for solar cells are demonstrated on industrial SHJ precursors. Inkjet- and FlexTrail-printing of NaOHaq are shown to be suitable to pattern the Al layer. Promising conversion efficiency comparable to screen-printing reference is reached on large area.