Search

Formamidinium lead triiodide (FAPbI3) perovskite without methylammonium and/or Cs cations is considered the most promising candidate for perovskite photovoltaics. However, the crystallization of photoactive α‐FAPbI3 requires high‐temperature annealing (≥150 °C) and a controlled humidity environment when methylammonium‐containing additives are absent. A methylammonium‐free ink is reported that enables low‐temperature (≤80 °C) crystallization of photoactive α‐FAPbI3 films, while also demonstrating compatibility with blade‐coating large‐area films in ambient air. The synergistical effects of methylphenyl sulfoxide and PbCl2 facilitate the formation of an intermediate phase of nanoscale‐disordered δ‐FAPbI3, which dramatically reduces the crystallization temperature of α‐FAPbI3 down to 80 °C and even below. The 80 °C crystalized α‐FAPbI3 exhibits reduced strain and improved uniformity compared to high‐temperature annealed counterparts. The synthesized ink and the corresponding intermediate precursor film are also found remarkably stable, allowing open‐air processing without the need for humidity control. Highly efficient n–i–p structured α‐FAPbI3 minimodules can be fabricated under an ambient environment RH 50% with the ink at 80 °C, achieving a power conversion efficiency of up to 22.4%. The discovery of the low‐temperature FAPbI3 ink paves a new avenue for printing perovskite solar cells and associated optoelectronic applications, accelerating the commercialization progress of perovskite materials. [ABSTRACT FROM AUTHOR]

A method for measuring light absorption using photothermal deflection spectroscopy (PDS) is investigated. Typical reflectance and transmittance (R & T) absorption measurements have low spectral resolution (SR) with standard setups. It is believed that absorption measurements using PDS solve this problem because of its high sensitivity, even at a high SR. However, accurate absorption measurements have not been obtained using conventional PDS. The reflectance of the sample must be considered in the absorptance calculations. Various absorption measurement methods are compared and a novel calculation method for accurate PDS absorption measurements is proposed. A sample with quantum structures is fabricated and PDS measurements are performed. Exciton absorption peaks are also observed. The high SR of PDS is demonstrated and the measured exciton absorption peaks are confirmed using piezoelectric photothermal measurements. Furthermore, it is confirmed that the absolute values of absorptance derived from the R & T and PDS measurements agree well. The new PDS absorption measurement technique enables to obtain accurate absorption characteristics, which are indispensable for designing and optimizing optoelectronic devices. [ABSTRACT FROM AUTHOR]

Consolidated tables showing an extensive listing of the highest independently confirmed efficiencies for solar cells and modules are presented. Guidelines for inclusion of results into these tables are outlined, and new entries since January 2024 are reviewed. [ABSTRACT FROM AUTHOR]

Despite its growing popularity as a solar material, there is no comprehensive reference to aid with determining various polymorphs of copper zinc tin sulfide (CZTS) in the lab. Understanding the diverse electronic, optical and vibrational properties of these polymorphs is crucial to further enhance the conversion efficiency of CZTS solar cells. Here, findings are presented that suggest the effective hole mass in a monoclinic polymorph, that is likely to form along with the more commonly reported tetragonal variations, is about 10 times heavier than that of its tetragonal counterparts, thereby affecting key attributes such as carrier transport and concentration. Among tetragonal polymorphs, the so‐called primitive mixed CuAu (PMCA) arrangement is likely to undergo a direct‐indirect gap transition due to internal strains. Optical absorption between different polymorphs could also vary by up to 90% in the visible spectrum. Finally, accurate Raman footprint of each polymorph is predicted to help establish a definitive method for their detection. From a modeling perspective, Becke‐Lee‐Yang‐Parr with spin‐orbit coupling is shown to be a superior yet 100X faster alternative to hybrid functionals when applied to studying electronic structure of CZTS. [ABSTRACT FROM AUTHOR]

Multidimensional simulations for diverse solar cells often encounter distinctive configurations, even when employing the same simulation software. The complexity and inefficiency of this process are further exacerbated when employing different simulators. From our extensive decade‐long experience in numerical simulations of diverse solar cells, we have identified ten common simulation steps intrinsic to typical electrical and optical simulations. Subsequently, we propose ten sets of variables that encompass all the relevant details required for these steps. To address the challenge of varying information requirements for each variable across different simulations, we assign a list, a versatile data type, to each variable. This approach, by design, enables concise, coherent, and flexible input, accommodating the unique demands of each simulation. However, to ensure unambiguous simulations, precise specifications for these variables are essential. Computer code has been successfully implemented to ensure adherence to specifications and expedite variable synchronization with Sentaurus, the de facto standard for device simulation. Within this framework, users are only tasked with editing variables in a plain text file, obviating the need for in‐depth knowledge of Sentaurus. This streamlines the prerequisites for engaging in numerical simulation significantly. Through thoughtful design considerations, we preserve the simulation capacity while simultaneously enhancing productivity considerably. This open‐source framework welcomes global collaboration within the photovoltaic community and has the potential to generate an extensive dataset for cost‐effective artificial intelligence training. [ABSTRACT FROM AUTHOR]

Kesterite is an earth‐abundant energy material with high predicted power conversion efficiency, making it a sustainable and promising option for photovoltaics. However, a large open circuit voltage Voc deficit due to non‐radiative recombination at intrinsic defects remains a major hurdle, limiting device performance. Incorporating Ge into the kesterite structure emerges as an effective approach for enhancing performance by manipulating defects and morphology. Herein, how different amounts of Ge affect the kesterite growth pathways through the combination of advanced microscopy characterization techniques are systematically investigated. The results demonstrate the significance of incorporating Ge during the selenization process of the CZTSSe thin film. At high temperature, the Ge incorporation effectively delays the selenization process due to the formation of a ZnSe layer on top of the metal alloys through decomposition of the Cu‐Zn alloy and formation of Cu‐Sn alloy, subsequently forming of Cu‐Sn‐Se phase. Such an effect is compounded by more Ge incorporation that further postpones kesterite formation. Furthermore, introducing Ge mitigates detrimental "horizontal" grain boundaries by increasing the grain size on upper layer. The Ge incorporation strategy discussed in this study holds great promise for improving device performance and grain quality in CZTSSe and other polycrystalline chalcogenide solar cells. [ABSTRACT FROM AUTHOR]

Oleanolic acid (OA) is a pentacyclic triterpene with reported protective effects against various diseases, including diabetes, hepatitis, and different cancers. However, the effects of OA on obesity‐induced muscle atrophy remain largely unknown. This study investigated the effects of OA on skeletal muscle production and proliferation of C2C12 cells. We report that OA significantly increased skeletal muscle mass and improved glucose intolerance and insulin resistance. OA inhibited dexamethasone (Dex)‐induced muscle atrophy in C2C12 myoblasts by regulating the PI3K/Akt signaling pathway. In addition, it also inhibited expression of MuRF1 and Atrogin1 genes in skeletal muscle of obese mice suffering from muscle atrophy, and increased the activation of PI3K and Akt, thereby promoting protein synthesis, and eventually alleviating muscle atrophy. Taken together, these findings suggest OA may have potential for the prevention and treatment of muscle atrophy. [ABSTRACT FROM AUTHOR]

Aim: Exercise can reduce body weight and promote white fat browning, but the underlying mechanisms remain largely unknown. This study investigated the role of fibronectin type III domain‐containing protein 5 (FNDC5)/Irisin, a hormone released from exercising muscle, in the browning of white fat in circulating extracellular vesicles (EVs). Methods: Mice were subjected to a 4 weeks of running table exercise, and fat browning was analyzed via histology, protein blotting and qPCR. Circulating EVs were extracted by ultrahigh‐speed centrifugation, and ELISA was used to measure the irisin concentration in the circulating EVs. Circulating EVs that differentially expressed irisin were applied to adipocytes, and the effect of EV‐irisin on adipocyte energy metabolism was analyzed by immunofluorescence, protein blotting, and cellular oxygen consumption rate analysis. Results: During sustained exercise, the mice lost weight and developed fat browning. FNDC5 was induced, cleaved, and secreted into irisin, and irisin levels subsequently increased in the plasma during exercise. Interestingly, irisin was highly expressed in circulating EVs that effectively promoted adipose browning. Mechanistically, the circulating EV‐irisin complex is transported intracellularly by the adipocyte membrane receptor integrin αV, which in turn activates the AMPK signaling pathway, which is dependent on mitochondrial uncoupling protein 1 to cause mitochondrial plasmonic leakage and promote heat production. After inhibition of the AMPK signaling pathway, the effects of the EV‐irisin on promoting fat browning were minimal. Conclusion: Exercise leads to the accumulation of circulating EV‐irisin, which enhances adipose energy metabolism and thermogenesis and promotes white fat browning in mice, leading to weight loss. [ABSTRACT FROM AUTHOR]

Poly[bis(4‐phenyl)(2,4,6‐trimethylphenyl)amine (PTAA) is one of the most efficient hole transport materials for p–i–n structured perovskite solar cells (PSCs). However, the hydrophobicity of PTAA causes wettability problems and is thereby associated with low yield and poor reproducibility. Herein, a new strategy for improving the perovskite precursor wettability on PTAA is developed. A Cu2(Thiourea)Br2 complex interfacial layer is introduced on the PTAA, improving the coverage of perovskite precursors and thereby the perovskite film. Partially dissolved Cu2(Thiourea)Br2 in the perovskite absorber further enhances band alignment and carrier extraction between layers. With the addition of Cu2(Thiourea)Br2 layer on nondoped PTAA, PSCs in p–i–n structure with a bandgap of 1.63 eV have achieved over 21% efficiency both on 0.1 and 1.0 cm2 sized devices with a significantly improved yield and reproducibility. Unencapsulated devices retain 100% of their initial efficiency after 2000 h at 65 °C. [ABSTRACT FROM AUTHOR]

Human skin comprises multiple hierarchical layers that perform various functions such as protection, sensing, and structural support. Developing electronic skin (E‐skin) with similar properties has broad implications in health monitoring, prosthetics, and soft robotics. While previous efforts have predominantly concentrated on sensory capabilities, this study introduces a hierarchical polymer system that not only structurally resembles the epidermis‐dermis bilayer structure of skin but also encompasses sensing functions. The system comprises a polymeric hydrogel, representing the "dermis", and a superimposed nanoporous polymer film, forming the "epidermis". Within the film, interconnected nanoparticles mimic the arrangement of interlocked corneocytes within the epidermis. The fabrication process employs a robust in situ interfacial precipitation polymerization of specific water‐soluble monomers that become insoluble during polymerization. This process yields a hybrid layer establishing a durable interface between the film and hydrogel. Beyond the structural mimicry, this hierarchical structure offers functionalities resembling human skin, which includes (1) water loss protection of hydrogel by tailoring the hydrophobicity of the upper polymer film; (2) tactile sensing capability via self‐powered triboelectric nanogenerators; (3) built‐in gold nanowire‐based resistive sensor toward temperature and pressure sensing. This hierarchical polymeric approach represents a potent strategy to replicate both the structure and functions of human skin in synthetic designs. [ABSTRACT FROM AUTHOR]

The organic spacer cation plays a crucial role in determining the exciton fine structure in 2D perovskites. Here, magneto‐optical spectroscopy is used to gain insight into the influence of the organic spacer on dark excitons in Ruddlesden–Popper (RP) perovskites. Using modest magnetic field strengths (<1.5 T), the optically forbidden dark exciton state can be identified and its emission properties significantly modulated via application of in‐plane magnetic fields, up to temperatures of 15 K. At low temperatures, an increase in collected photoluminescence efficiency of >30% is demonstrated, signifying the critical role of the dark exciton state for light‐emitting applications of 2D perovskites. The exciton fine structure and the degree of magnetic‐field‐induced mixing are significantly impacted by the choice of organic spacer cation, with 4–methoxyphenylethylammonium (MeO‐PEA) showing the largest effect due to larger bright–dark exciton splitting. This study distinguishes between interior (bulk) and surface dark‐exciton emission, showing that bright–dark exciton splitting differs between the interior and surface. The results emphasize the significance of the organic spacer cation in controlling the exciton fine structure in 2D perovskites and have important implications for the development of optoelectronic technology based on 2D perovskites. [ABSTRACT FROM AUTHOR]

Tandem solar cells are rationally designed and fabricated by stacking multiple subcells to achieve power conversion efficiency well above the Shockley‐Queisser (SQ) limit. There is a large selection pool for the subcell candidates, such as Si, III–V, Kesterite, Perovskite, and organic solar cells. A series of different combinations of these subcells have been successfully demonstrated in practical tandem solar cell devices. However, there has not been a systematic summary of how to connect subcells in a tandem solar cell using a practical, cost‐effective, and efficiency‐beneficial fashion. In this work, the connection manners of subcells within a tandem cell are classified into three main categories, performing sequential growth, using the physical connection, and applying an intermediate layer, focusing on systematical description of intermediate layers using different materials. The advantages and disadvantages of these connection methods and their applicability to tandem cell types are further elaborated using two typical example models, III–V/Si and Perovskite inclusive tandem cell devices. Eventually, this work can provide useful guidance on how to carry out a suitable intermediate connection in the design of tandem solar cells depending on the selected subcells and device structure. [ABSTRACT FROM AUTHOR]

Consolidated tables showing an extensive listing of the highest independently confirmed efficiencies for solar cells and modules are presented. Guidelines for inclusion of results into these tables are outlined, and new entries since January 2023 are reviewed. [ABSTRACT FROM AUTHOR]

Obesity is a common chronic metabolic disease that induces chronic systemic inflammation in the body, eventually leading to related complications such as insulin resistance (IR), type 2 diabetes mellitus, and metabolic syndromes such as cardiovascular disease. Exosomes transfer bioactive substances to neighboring or distal cells through autosomal, paracrine, or distant secretion, regulating the gene and protein expression levels of receptor cells. In this study, we investigated the effect of mouse bone marrow mesenchymal stem cell‐derived exosomes (BMSC‐Exos) on high‐fat diet obese mice and mature 3T3‐L1 adipocyte models of IR. BMSC‐Exo treatment of obese mice promoted their metabolic homeostasis, including reduction of obesity, inhibition of M1‐type proinflammatory factor expression, and improvement of insulin sensitivity. In vitro analysis revealed that BMSC‐Exos improved IR and lipid droplet accumulation in mature 3T3‐L1 adipocytes treated with palmitate (PA). Mechanistically, BMSC‐Exos cause increased glucose uptake and improved IR in high‐fat chow‐fed mice and PA‐acting 3T3‐L1 adipocytes by activating the phosphoinositide 3‐kinases/protein kinase B (PI3K/AKT) signaling pathway and upregulating glucose transporter protein 4 (GLUT4) expression. This study offers a new perspective for the development of treatments for IR in obese and diabetic patients. [ABSTRACT FROM AUTHOR]

Kesterite Cu2ZnSn(S,Se)4 (CZTSSe) with earth‐abundant and environmental‐benign constituents has been regarded as a promising solar energy harvesting material for green and cost‐effective photovoltaic applications. The record efficiency of CZTSSe solar cells has recently been refreshed twice after years‐long stagnation, keeping it in the spotlight. Nevertheless, the champion efficiency of 13.6% is still far behind its counterpart Cu(In,Ga)Se2 (CIGS) (23.35%) despite being endowed with a similar electronic structure and nearly‐identical device architecture. In fact, CZTSSe solar cells are more susceptible to non‐radiative recombination at bulk and interfaces, which must be improved for further efficiency advancement. In this review, the state‐of‐art strategies to enhance the power conversion efficiency of CZTSSe solar cells are summarized and discussed, with focus given to three critical device regions i) kesterite absorber, ii) buffer/kesterite interface, and iii) kesterite/back contact interface. With the further elucidation of the latest progress and disclosure of fundamental mechanisms, novel insights toward high‐efficiency kesterite solar cells are proposed. [ABSTRACT FROM AUTHOR]

Earth‐abundant and air‐stable Cu2BaSnS4−xSex (CBTSSe) and related thin‐film absorbers are regarded as prospective options to meet the increasing demand for low‐cost solar cell deployment. Devices based on vacuum‐deposited CBTSSe absorbers have achieved record power conversion efficiency (PCE) of 5.2% based on a conventional device structure using CdS buffer and i‐ZnO/indium tin oxide (ITO) window layers, with open‐circuit voltage (VOC) posing the major bottleneck for improving solar cell performance. The current study demonstrates a >20% improvement in VOC (from 0.62 to 0.75 V) and corresponding enhancement in PCE (from 5.1% to 6.2% without antireflection coating; to 6.5% with MgF2 antireflection coating) for solution‐deposited CBTSSe solar cells. This performance improvement is realized by introducing an alternative successive ionic layer adsorption and reaction‐deposited Zn1−xCdxS buffer combined with sputtered Zn1−xMgxO/Al‐doped ZnO window/top contact layer, which offers lower electron affinities relative to the conventional CdS/i‐ZnO/ITO stack and better matching with the low electron affinity of CBTSSe. A combined experimental (temperature‐ and light intensity‐dependent VOC measurements) and device simulation (SCAPS‐1D) evaluation points to the importance of addressing relative band offsets for both the buffer and window layers relative to the absorber in mitigating interfacial recombination and optimizing CBTSSe solar cell performance. [ABSTRACT FROM AUTHOR]

Effectively incorporating alkali metals or alternative isovalent cations into Cu2ZnSnS4 (CZTS) is considered one of the most promising strategies for realizing a step‐change improvement in the photovoltaic device performance. Herein, the local distribution of Na and Cd by a moisture‐assisted postdeposition annealing (MAPDA) treatment combined with a subsequent heterojunction heat treatment is manipulated. The MAPDA treatment facilitates the controllable reduction of the Na concentration, thus promoting the spontaneous diffusion of Cd into the heterojunction region. A subsequent 150 °C low‐temperature heterojunction heat treatment after MAPDA treatment enables further modification of Cd and Na distributions, leading to significantly enhanced optoelectronic properties at the CZTS/CdS heterojunction and greatly improved device performance with a peak conversion efficiency of 9.40%. The modified heterojunction significantly improves quasi‐Fermi‐level splitting under low‐photon injection, making CZTS solar cells more feasible in low‐light applications. This work provides an effective approach to simultaneously manipulate the distribution of Na and Cd, enabling pronounced modification of the heterojunction quality of CZTS solar cells and boost of conversion efficiencies. Insights gleaned herein may also be applicable to manipulating other critical trace elements in chalcogenide materials in general. [ABSTRACT FROM AUTHOR]

Antimony sulfide (Sb2S3) is a promising wide‐bandgap photovoltaic material, and a potential top‐cell candidate for next‐generation Si‐based tandem solar cells. The most widely used electron transport layers in Sb2S3 solar cells are TiO2 and CdS, which present an obvious performance variation in open‐circuit voltage (VOC) and short current (Jsc). However, the mechanisms behind the performance disparity because of the electron transport layer (ETL) have not been disclosed. Herein, a comprehensive comparative study of using TiO2 and CdS as the electron transport layers in Sb2S3 solar cells is presented, which covers their influence on preferential crystal orientation, band alignment, interface, and bulk defects. It is found that the CdS ETL results in less interfacial defects and more favorable band alignment, enabling a higher VOC, while the high resistance of the CdS film and parasitic light absorption restricts the JSC. The findings provide a substantial guidance on device optimization for Sb2S3 solar cells. [ABSTRACT FROM AUTHOR]

This article, titled "Methylammonium-Free Ink for Low-Temperature Crystallization of α-FAPbI3 Perovskite," was published in the journal Advanced Energy Materials. The authors, Tian Hou, Meng Zhang, Xiaoran Sun, Yihao Wang, Kaipeng Chen, Zhipeng Fu, Mingrui He, Xu Liu, Ziheng Liu, Yuelong Huang, Martin A. Green, and Xiaojing Hao, discuss a new method for fabricating α-FAPbI3 perovskite at low temperatures without the use of methylammonium (MA). The article includes an image illustrating the phase transition from hexagonal δ-FAPbI3 to cubic α-FAPbI3, and explains how the addition of PbCl2 and MPSO helps facilitate this transition. For more details, readers are directed to the full article. [Extracted from the article]

Sulfide kesterite Cu2ZnSnS4 (CZTS) solar cells, containing earth‐abundant and environmentally benign constituents, are regarded as promising candidates for thin‐film photovoltaic technologies. CZTS device performance, however, is currently limited by severe nonradiative recombination caused by abundant deep‐level defects. Herein, an effective defect engineering approach for high bandgap CZTS solar cells using a newly introduced moisture‐assisted post‐deposition annealing treatment is reported. This treatment modifies the local chemical composition within the heterojunction and CZTS grain boundaries and enhances the incorporation of Cd within the CZTS layer during CdS deposition. Cd not only accumulates at the grain boundaries, but it also presents in grain interiors where it occupies Cu lattice sites. The overall modification of the local chemical environment suppresses deep level defects and activates relatively shallow acceptor CuZn antisites and Cu vacancies, giving rise to remarkably improved device performance. This work opens a new direction for defect engineering of kesterite materials, which may also be applicable to other thin film semiconductors. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs) with a power conversion efficiency (PCE) overpassing 25% have proved to be the most promising competitor for the next‐generation photovoltaic technology. Massive efforts are devoted to the improvement of the performance and stability of PSCs, whereas the hole transport layer (HTL) has attracted significant interest. Among diverse hole transport materials, poly[bis(4‐phenyl)(2,4,6‐trimethylphenyl)amine (PTAA) is one of the most promising candidates due to its ease of fabrication, transparency to visible light, mechanical flexibility, conductivity, and stability. Over the past few years, there has been an increasing amount of research using PTAA as the HTL first in n–i–p and then in p–i–n PSCs with extended applications in flexible, large‐area, and tandem devices. Herein, a progress review on PTAA for PSC applications is provided, which enables a better understanding of the advantages and disadvantages of PTAA, as well as the approaches to fully realizing its tremendous potential. The emerging and promising research directions for PTAA‐based PSCs are discussed, shedding light on the practical applications of PTAA. [ABSTRACT FROM AUTHOR]

Consolidated tables showing an extensive listing of the highest independently confirmed efficiencies for solar cells and modules are presented. Guidelines for inclusion of results into these tables are outlined, and new entries since January 2022 are reviewed. An appendix describing temporary electrical contacting of large‐area solar cells approaches and terminology is also included. [ABSTRACT FROM AUTHOR]

Antimony sulfide is an emerging 1D nontoxic Earth‐abundant photovoltaic material with favorable wide bandgap as a suitable top‐cell candidate for multijunction tandem solar cells. However, the current fabrication technology for Sb2S3 solar cells relies heavily on a high‐purity Sb2S3 source, which limits its large‐scale deployment. Therefore, it is attractive to fabricate the Sb2S3 solar cells directly from the raw stibnite source, which can be cost effective by avoiding the complicated, costly purification and refinement process of the stibnite ore, while reducing process‐emitted pollution. Herein, high‐quality Sb2S3 films (thickness: ≈1 μm) by the vapor transport deposition of raw stibnite ore powder are obtained, followed by a sulfurization process to remove the surface oxides and facilitate alkali element redistribution. In this way, the particle size is increased from ≈500 nm to ≈1.5 μm, the carrier concentration of the Sb2S3 film is increased from ≈1015 to ≈1016 cm−3, and the power conversion efficiency of Sb2S3 solar cell is increased by more than two times. Through the elemental distribution analysis, it is found that it is the redistribution of alkali elements introduced from the natural stibnite ore that induces the grain growth, contributes toward defect suppression, and leads toward enhanced device performance. [ABSTRACT FROM AUTHOR]

Consolidated tables showing an extensive listing of the highest independently confirmed efficiencies for solar cells and modules are presented. Guidelines for inclusion of results into these tables are outlined, and new entries since June 2021 are reviewed. [ABSTRACT FROM AUTHOR]

Selective contact annealing is developed to improve the performance of bifacial‐grid III–V top cells bonded on glass by epoxy resin for Si‐based tandem solar cells. The annealing method can minimize the damage to the bonding layer and is compatible with the industrial evaporation technique for contact fabrication. The improvement of the front contact quality by selective annealing treatments is demonstrated through optical and electrical characterization which shows a significantly enhanced III–V device performance. Furthermore, a fitting model is established to reveal the mechanism underlying the performance improvement through the reduction of contact resistances and the bad contact area. Herein, an effective annealing approach to fabricate high‐quality metal–semiconductor contacts for devices with poor thermal resistivity is demonstrated, which can be used in polymer‐bonded top cells in Si‐based tandem solar cells and other flexible optoelectronic devices on polymer substrates. [ABSTRACT FROM AUTHOR]

Herein, an electroluminescence (EL)‐based imaging method to detect broken fingers in solar cells is presented. The method is based on the ratio of two EL images taken with different paths of the injected current. The resultant high‐contrast images allow unambiguous separation of various series resistance‐related problems and hence the potential application of identifying broken fingers. The method can be applied to solar cells with both full and partial rear contacts. It can be easily implemented in commercial luminescence imaging systems, significantly extending their capabilities. [ABSTRACT FROM AUTHOR]

Kesterite Cu2ZnSnS4 (CZTS) solar cell has emerged as one of the most promising thin‐film photovoltaic technologies that allows for cheap, clean, and efficient renewable power in the future. Nevertheless, limited by the large photovoltage deficit caused by severe interface recombination, the potential of CZTS solar cells is far from being fully tapped. Herein, it is demonstrated that the carrier density of the CZTS absorber and the acceptor‐like interface defects are two critical factors governing the interface recombination in addition to the unfavorable conduction band alignment. Results of device simulation suggest that passivating the acceptor‐like interface defects combined with appropriate absorber carrier density is the essential way to promote the photovoltage and efficiency of CZTS solar cells to a more competitive level. It is believed that these results could be generally applicable to the interface recombination of other heterojunction solar cells. [ABSTRACT FROM AUTHOR]

The performance of kesterite Cu2ZnSn(S,Se)4 (CZTSSe) solar cell is known to be severely limited by the nonradiative recombination near the heterojunction interface and within the bulk of the CZTSSe absorber resulting from abundant recombination centers and limited carrier collection efficiency. Herein, nonradiative recombination is simultaneously reduced by incorporating small amounts of Ge and Cd into the CZTSSe absorber. Incorporation of Ge effectively increases the p‐type doping, thus successfully improving the bulk conductance and reducing the recombination in the CZTSSe bulk via enhanced quasi‐Fermi level splitting, while the incorporation of Cd greatly reduces defects near the junction region, enabling larger depletion region width and better carrier collection efficiency. The combined effects of Cd and Ge incorporation give rise to systematic improvement in open‐circuit voltage (VOC), short‐circuit current density (JSC), and fill factor (FF), enabling a high conversion efficiency of 11.6%. This study highlights the multiple cation incorporation strategy for systematically manipulating the opto‐electronic properties of kesterite materials, which may also be applicable to other semiconductors. [ABSTRACT FROM AUTHOR]

Consolidated tables showing an extensive listing of the highest independently confirmed efficiencies for solar cells and modules are presented. Guidelines for inclusion of results into these tables are outlined, and new entries since January 2021 are reviewed. [ABSTRACT FROM AUTHOR]

Earth‐abundant and environmentally benign kesterite Cu2ZnSn(S,Se)4 (CZTSSe) is a promising alternative to its cousin chalcopyrite Cu(In,Ga)(S,Se)2 (CIGS) for photovoltaic applications. However, the power conversion efficiency of CZTSSe solar cells has been stagnant at 12.6% for years, still far lower than that of CIGS (23.35%). In this report, insights into the latest cutting‐edge strategies for further advance in the performance of kesterite solar cells is provided, particularly focusing on the postdeposition thermal treatment (for bare absorber, heterojunction, and completed device), alkali doping, and bandgap grading by engineering graded cation and/or anion alloying. These strategies, which have led to the step‐change improvements in the power conversion efficiency of the counterpart CIGS solar cells, are also the most promising ones to achieve further efficiency breakthroughs for kesterite solar cells. Herein, the recent advances in kesterite solar cells along these pathways are reviewed, and more importantly, a comprehensive understanding of the underlying mechanisms is provided, and promising directions for the ongoing development of kesterite solar cells are proposed. [ABSTRACT FROM AUTHOR]

Halide perovskite‐based photovoltaic (PV) devices have recently emerged for low energy consumption electronic devices such as Internet of Things (IoT). In this work, an effective strategy to form a hole‐selective layer using phenethylammonium iodide (PEAI) salt is presented that demonstrates unprecedently high open‐circuit voltage of 0.9 V with 18 µW cm−2 under 200 lux (cool white light‐emitting diodes). An appropriate post‐deposited amount of PEAI (2 mg) strongly interacts with the perovskite surface forming a conformal coating of PEAI on the perovskite film surface, which improves the crystallinity and absorption of the film. Here, Kelvin probe force microscopy results indicate the diminished potential difference across the grain boundaries and grain interiors after the PEAI deposition, constructing an electrically and chemically homogeneous surface. Also, the surface becomes more p‐type with a downshift of a valence band maximum, confirmed by ultraviolet photoelectron spectroscopy measurement, facilitating the transport of holes to the hole transport layer (HTL). The hole‐selective layer‐deposited devices exhibit reduced hysteresis in light current density–voltage curves and maintain steadily high fill factor across the different light intensities (200–1000 lux). This work highlights the importance of the HTL/perovskite interface that prepares the indoor halide perovskite PV devices for powering IoT device. [ABSTRACT FROM AUTHOR]

Lithium incorporation in kesterite Cu2ZnSn(S,Se)4 (CZTSSe) materials has been experimentally proven effective in improving electronic quality for application in photovoltaic devices. Herein, a feasible and effective solution‐based lithium post‐deposition treatment (PDT), enabling further efficiency improvement on the high‐performance baseline is reported and the dominant mechanism for this improvement is proposed. In this way, lithium is uniformly incorporated into grain interiors (GIs) without segregation at grain boundaries (GBs), which can occupy the Zn sites with a high solubility in the CZTSSe matrix, producing high density of LiZn antisites with shallower acceptor levels than the intrinsic dominant defect (CuZn antisites). As a result, CZTSSe absorber with better p‐type doping is obtained, leading to a pronounced enhancement in fill factor and a corresponding gain in open‐circuit voltage and short‐circuit current and consequently a significant efficiency boost from 9.3% to 10.7%. This work provides a feasible alternative alkali‐PDT treatment for chalcogenide semiconductors and promotes a better understanding of the mechanism of Li incorporation in kesterite materials. [ABSTRACT FROM AUTHOR]

Majority carrier mobility is one of the most fundamental and yet important carrier transport parameters determining the optimal device architecture and performance of the emerging antimony chalcogenide solar cells. However, carrier mobility measurements based on the Hall effect have limitations for these highly anisotropy materials due to the discrepancy of transport directions under Hall measurement and device operation. Herein, a defect‐resolved mobility measurement (DRMM) method enabling the evaluation of effective majority carrier mobility from a working device without such limitations is presented. Using this method, comprehensive information about the carrier transport in representative Sb2S3 and Sb2Se3 solar cells is extracted. Though with preferred [hk1]‐crystalline orientation, Sb2S3 and Sb2Se3 still suffer from extremely low carrier mobility and low carrier density, respectively, resulting in large bulk resistance and poor carrier collection efficiency. Further crystalline structure analysis discloses that crystalline defects such as dislocations may significantly constrain carrier transport in these low‐dimensional materials. These results suggest that a p‐i‐n device architecture with fully depleted absorber is a promising optimization approach for further efficiency advances of antimony chalcogenide solar cells. [ABSTRACT FROM AUTHOR]

Metal oxide nanoparticles and carbon nanoparticles, as common nanoparticles (NPs), can cause autophagy in certain cells, which will lead to biohealth risk issues. This study determined the difference in autophagy induced by zinc oxide nanoparticles (ZnO NPs) and single‐walled carbon nanotubes (SWCNTs) in respiratory epithelial cells. ICP‐OES results showed that NPs uptake as well as the intercellular contents of particles affected cytotoxicity in a dose‐dependent manner. ZnO NPs‐30 nm had a distinct green dot structure representing autophagy, the SWCNTs exposure group had a few green light spots at a concentration of 10 μg/L. The ROS content of the ZnO NP‐30 nm exposure group had the greatest increase at a concentration of 1000 μg/L, which was 2.5 times higher than that of the control, the SWCNTs exposure group showed a 2.2‐fold increase. A slight downregulation of p‐mTOR was detected, and the ZnO NPs‐30 nm treatment group had the significant downregulation rate. The gene and protein expression levels of Beclin‐1 and LC3B were upregulated as the exposure concentration increased. The protein expression of Beclin‐1 and LC3B in the 1000 μg/L ZnO NPs‐30 nm exposure group were 5.21 times and 4.12 times that of the control, respectively. The mRNA expression of Beclin‐1 and LC3B in the 1000 μg/L ZnO NPs‐30 nm exposure group were 5.04 times and 3.61 times that of the control, respectively. At any concentration, the effect of ZnO NPs‐30 nm was greater than that of the SWCNTs. Interaction and crosstalk analysis showed that exposure to ZnO NPs‐30 nm caused autophagy through the aggregation of undegraded autophagosomes, whereas SWCNTs exposure induced diminished intercellular oxidative stress to inhibit autophagy. Therefore, this study demonstrated that the effects of autophagy induced by ZnO NPs‐30 nm and SWCNTs were different. The health risks of ZnO‐30 nm NPs are higher than those of SWCNTs. [ABSTRACT FROM AUTHOR]

The anomalous optoelectronic properties of a quasi‐vertical orientated Chalcostibite CuSbS2 thin film synthesized on glass substrate are studied in detail. Two well‐separated absorption edges of CuSbS2 are identified by photothermal‐deflection spectroscopy (PDS) at 1.48 and 0.90 eV. The formation mechanism of the 0.9 eV infrared edge is found to be crystal orientation related. The properties of the 0.9 eV absorption edge are subject to detailed investigation using temperature‐dependent photoluminescence (TDPL) characterization, which attribute the origin of this phenomenon to a deep‐level defect state near the mid‐bandgap of CuSbS2. [ABSTRACT FROM AUTHOR]

Consolidated tables showing an extensive listing of the highest independently confirmed efficiencies for solar cells and modules are presented. Guidelines for inclusion of results into these tables are outlined, and new entries since January 2020 are reviewed. [ABSTRACT FROM AUTHOR]

For semitransparent devices with n‐i‐p structures, a metal oxide buffer material is commonly used to protect the organic hole transporting layer from damage due to sputtering of the transparent conducting oxide. Here, a surface treatment approach is addressed for tungsten oxide‐based transparent electrodes through slight modification of the tungsten oxide surface with niobium oxide. Incorporation of this transparent electrode technique to the protective buffer layer significantly recovers the fill factor from 70.4% to 80.3%, approaching fill factor values of conventional opaque devices, which results in power conversion efficiencies over 18% for the semitransparent perovskite solar cells. Application of this approach to a four‐terminal tandem configuration with a silicon bottom cell is demonstrated. [ABSTRACT FROM AUTHOR]

Solar energy is one of the most abundant renewable energy sources. For efficient utilization of solar energy, photovoltaic technology is regarded as the most important source. However, due to the intermittent and unstable characteristics of solar radiation, photoelectric conversion (PC) devices fail to meet the requirements of continuous power output. With the development of rechargeable electric energy storage systems (ESSs) (e.g., supercapacitors and batteries), the integration of a PC device and a rechargeable ESS has become a promising approach to solving this problem. The so‐called integrated photorechargeable ESSs which can directly store sunlight generated electricity in daylight and reversibly release it at night time, has a huge potential for future applications. This review summarizes the development of several types of mainstream integrated photorechargeable ESSs and introduces different working mechanisms for each photorechargeable ESS in detail. Several general perspectives on challenges and future development in the field are also provided. [ABSTRACT FROM AUTHOR]

A proof‐of‐concept tandem solar cell using Sb2S3 and Sb2Se3 as top and bottom cell absorber materials is demonstrated. The bandgaps of Sb2S3 and Sb2Se3 are 1.74 and 1.22 eV, perfectly satisfying the requirement of tandem solar cells. The application of few‐layer graphene enables high transmittance and excellent interfacial contact in the top subcell. By controlling the thickness of the top cell for maximizing the spectral application, the tandem device delivers a power conversion efficiency of 7.93%, which outperforms the individually optimized top cell (5.58%) and bottom cell (6.50%). Mechanistical investigation shows that the tandem device is able to make up voltage loss in the subcells, which is a critical concern in the current antimony chalcogenide solar cells. This study provides an alternative approach to enhancing the energy conversion efficiency of antimony selenosulfide. [ABSTRACT FROM AUTHOR]

To improve the crystallinity and overall film quality of the light absorbing layer is vital to further enhance the performance of sulfide Kesterite Cu2ZnSnS4 (CZTS) solar cells, especially for all solution‐processed devices using ball‐milling processed CZTS that generally leads to poor crystallization. In this work, a novel treatment method involving high‐boiling‐point solvent (HBPS), via simply spinning oleic acid (OA) solution onto CZTS precursor film coupled with an elongated annealing duration, was for the first time reported that enabled not only reduced surface roughness, but considerably increased crystalline of CZTS film. This is corroborated by an enhanced XRD intensity by eight ‐fold in conjunction with a five‐fold increased steady‐state PL intensity, the latter of which also indicates an improved CdZnS/CZTS heterojunction quality. Combined with all solution‐processed buffer layer and contact material, device using HBPS‐treated ball‐milling processed CZTS absorber yielded a power conversion efficiency of 6.1%, which is the highest reported for all solution‐processed pure‐sulfide CZTS solar cells. The HBPS‐treatment approach developed in this work is simple and effective, and in principle can promisingly be applied to any film to work synergistically with thermal annealing treatment, leading to simultaneously enhanced crystallinity and overall film quality while maintaining its planeness. A one‐step high‐boiling‐point solvent treating method is developed to form nearly micron‐sized pure‐sulfide Cu2ZnSnS4 large grains. Oleic Acid is spin‐coated onto CZTS precursor before annealing, combining with extended annealing duration, to enhance crystallinity, enlarge grain size and reduce surface roughness of CZTS film simultaneously. Based on this high‐boiling‐point solvent treatment. all solution‐processed (sputtering‐free) CZTS solar cell achieves competitive photovoltaic performance. [ABSTRACT FROM AUTHOR]

The earth‐abundant and environmentally‐friendly CuSbS2 solar cells have been struggling with low device performance, especially poor open circuit voltage (Voc). In this work, post‐annealing treatment of the CuSbS2/CdS heterojunction performed on CuSbS2‐based solar cells was firstly reported. With this treatment, we demonstrated CuSbS2 solar cells with a record Voc of 622 mV. The improvement of device performance was found peaked at 250°C post‐annealing which mainly benefits from the significantly boosted open‐circuit voltage and short‐circuit current. The study of microstructure by high‐resolution transmission electron microscopy revealed that such improvement could be attributed to the formation of epitaxial CuSbS2/CdS hetero‐interface upon heat treatment, which reduces the interface defect density that may lead to reduced Voc deficit. Besides, results of photoluminescence and time‐resolved photoluminescence measurements also indicated improved electrical properties of completed devices with higher photoluminescence intensity and longer minority carrier lifetime. We demonstrated significant improvement in efficiency (particularly in the Voc and Jsc) for CuSbS2 solar cells by post‐heat treatment of the CuSbS2/CdS heterojunction. The underlying correlation between post‐heat treatment and device performance reveals that the post‐heat treatment on the heterojunction leads to (1) the transformation from amorphous to epitaxial relationship of CuSbS2/CdS hetero‐interface and (2) simultaneously improved absorber quality. [ABSTRACT FROM AUTHOR]

Abstract: In this research, a new route of surface passivation is reported by introducing hydrogen from the atomic layer deposited (ALD) Al2O3 layer into pure sulfide Cu2ZnSnS4 (CZTS) solar cells. Different amounts of hydrogen are incorporated into the Cu2ZnSnS4/CdS interface through controlling the thickness of the ALD‐Al2O3 layer. The device with three cycles of ALD‐Al2O3 yields the highest efficiency of 8.08% (without antireflection coating) with improved open‐circuit voltage of up to 70 mV. With closer examination on the passivation route of ALD‐Al2O3, it is revealed by the surface chemisty study that the Al2O3 can be etched away by ammonium hydroxide in the CdS buffer deposition process. Instead, the hydrogen is detected within a shallow depth from the CZTS surface, and makes a significant difference in the measured distribution of contact potential difference and device performance. This may be interpreted by the effect of hydrogen passivation of the CZTS surface by curing dangling bonds at the surface of CZTS grains. This work may provide a new direction of further improving the performance of kesterite solar cells. [ABSTRACT FROM AUTHOR]