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M‐series molecules are one kind of promising acceptor‐donor‐acceptor (A‐D‐A)‐type acceptors for constructing high‐performance organic solar cells (OSCs). However, their power conversion efficiencies (PCEs) are lagging behind that of current state‐of‐the‐art OSCs, limited by the relatively low fill factor (FF) and photocurrent. Herein, combined strategies of layer‐by‐layer (LBL) deposition and interface engineering are conducted to systematically improve light utilization and thus PCEs for M36‐based OSCs. Through choosing a proper processing solvent, a PCE of 17.3% with an FF of 77.9% is achieved for the resulting LBL devices, much higher than those (15.9%/74.0%) from the blend‐casting devices. The improvement is assigned to the favorable morphological evolution that facilitates carrier generation and transport as well as reduces charge recombination. More importantly, light‐harvesting of the active layers can be enhanced upon employing a self‐assembled monolayer of (2‐(9H‐carbazol‐9‐yl)ethyl)phosphonic acid (2PACz) instead of the widely used PEDOT:PSS as the hole‐selecting layer, due to the decreased parasitic absorption of the former. Consequently, 2PACz‐based LBL devices exhibit significantly increased photocurrent, affording a PCE up to 18.2%, which is the highest among the reported A‐D‐A‐type acceptor‐based OSCs. These results deliver important strategies to enhance the performance of OSCs and thus highlight the great potential of M‐series acceptors for practical applications. [ABSTRACT FROM AUTHOR]

Porphyrin derivatives are widely used as donors in organic solar cells (OSCs) due to their excellent optical and electrochemical properties. Although porphyrins can be functionalized at the meso‐ and β‐positions, only meso‐functionalized porphyrins have been reported as OSCs. Consequently, a direct comparison of the properties of porphyrins functionalized at these two positions is needed. The synthesis of two similar D–π–A–π–D materials is described herein and these compounds contain benzothiadiazole as the acceptor core and two Ni‐porphyrins as donors functionalized at the meso‐ and β‐positions to give RC19 and RC20, respectively. The optical and electrochemical properties of these compounds are reported. All‐small‐molecule OSCs based on RC19:TOCR1 and RC20:TOCR1 active layers show power conversion efficiencies (PCEs) of 13.72% and 5.20%, respectively. It should be noted that the PCE of 13.72% obtained for RC19:TOCR1 devices is, to one's knowledge, the highest value reported for porphyrin‐based binary OSCs. The higher PCE obtained for RC19 is due to its higher photon harvesting ability, more efficient exciton dissociation and charge transfer, balanced charge transport, and lower bimolecular and trap‐assisted recombination. [ABSTRACT FROM AUTHOR]

The goal of bifacial technology is to increase the efficiency of solar cells (SC) by capturing albedo sunlight and converting it to electrical energy. The use of triple‐cation mixed‐halide perovskite solar cells (PSC) has sparked a lot of curiosity and could be the potential for improved power conversion efficiency (PCE) associated with traditional PSCs. Herein, n–i–p‐configured triple‐cation mixed‐halide‐based bifacial PSC is studied using the SC capacitance simulator 1D tool. Through our simulation, the impact of thickness in electron and hole transport layers (ETL and HTLs), defect density, doping density, and the thickness of the light‐harvesting layer on the device performance is examined. With an optimal design, the device exhibits an absolutely staggering efficiency of 25.28% from the front side and around 17.19% from the rear. This cell, due to its high albedo absorption, linearly enhances the short‐circuit current; hence, it overcomes the classical current‐matching limit of ordinary PSCs. The proposed device FTO/TiO2/[Cs0.05(MA0.17FA0.83)0.95Pb(I0.83Br0.17)3]/CuSbS2 has a remarkable efficiency that increases linearly with albedo, making it very appealing for new, high‐efficiency solar applications. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSC) are a potential candidate for next‐generation photovoltaic technology. Despite the significant advancements in the field of PSCs, the ongoing development of stable and efficient metal halide perovskite materials, along with their successful integration into photovoltaic applications, remains challenges. These challenges originate from the diverse range of device structures and perovskite compositions, requiring meticulous consideration and optimization. Traditional trial‐and‐error methods are characterized by their sluggishness and labor‐intensive nature. Recently, the emergence of extensive datasets and advancements in computer hardware have facilitated the utilization of machine learning (ML) across multiple domains, including in various fields for material discovery and experimental optimization. Herein, the fundamental procedure of ML is briefly introduced, and latest progress of ML in the materials development and solar cell fabrication is comprehensively reviewed. The utilization of ML in PSCs at all stages of design can be categorized into four main areas: screening perovskite material, fabrication process optimization, device structure optimization, and understanding mechanism. The challenges and outlooks on the future development of ML are finally discussed. It is highly expected that this review can offer valuable guidance for the design and development of highly efficient and stable PSCs. [ABSTRACT FROM AUTHOR]

Herein, FTO/TiO2/Sb2S3/Au solar cell characteristics via SCAPS‐1D modeling are examined. The research begins with device modeling of the Sb2S3 conventional solar cell based on experimental data, which results in excellent agreement with the power conversion efficiency recorded in the literature of ≈4.72%. The influence of several factors on the characteristics of conventional solar cells is then investigated, including Sb2S3 thickness, carrier concentration, bulk and interface defects, and buffer layer type (TiO2, WS2, and CdS). An optimal efficiency of 9.97%, open‐circuit voltage (Voc) of 0.96 V, short‐circuit current (Jsc) of 19.69%, and fill factor (FF) of 52.26% are found for the FTO/WS2/Sb2S3/Au optimized solar cell. Finally, the influence of NiO as the back surface field and parasitic resistance (Rs and Rsh) on the performance of Sb2S3 solar cells is investigated. The innovative solar cell design (FTO/WS2/Sb2S3/NiO/Au) with NiO thickness of 20 nm, Rs < 2 Ω cm−2, and Rsh > 700 Ω cm−2 yields a high efficiency of more than 14.38%, FF > 68.93%, Voc > 1 V, and Jsc > 20.67 mA cm−2. These qualities allow for the large‐scale manufacture of a solar cell by including it in a manufacturing workflow. [ABSTRACT FROM AUTHOR]

The electrical properties of hole transport layers (HTL) are critical factors for the high performance of lead sulfide quantum dot solar cells (PbS CQDSCs). Herein, the impacts of doping the organic HTL PTB7‐Th with lithium bis(trifluoromethanesulfonimide) (LiTSFI) on the performance of quantum dot solar cells are explored and a notable enhancement in the fill factor is observed. A series of analytical characterizations of the doped HTLs are performed and it is found that doping with LiTFSI significantly deepens the Fermi level of the HTL, thereby improving the charge separation ability within the devices. Additionally, the conductivity of doped HTL is also improved. By optimizing the doping conditions, the doped device achieves a maximum power conversion efficiency of 12.68%. This doping strategy of organic HTL promotes the development of lead sulfide quantum dot solar cell techniques. [ABSTRACT FROM AUTHOR]

Tin oxide has been the mainstream as the electron transport layer for highly efficient perovskite solar cells due to advantages such as high mobility, high transmittance, and strong UV stability. Realizing high‐quality SnO2 layer at low temperature can widen the range of potential applications on both rigid and flexible substrates. Herein, a seed‐assisted growth strategy is developed for the preparation of SnO2 layer at low temperature (100 °C) and the seeds in precursor solution provide preferential nucleation sites. The SnO2 layer via seed‐assisted growth exhibits higher conductivity and mobility which are more than twice those of control samples because of enhanced crystallinity. The resulting solar cells show high Voc of 1.189 V, contributing to a high power conversion efficiency of 25.26%. To current knowledge, this is the highest efficiency for perovskite solar cells with SnO2 layer formed at low temperature (≤100 °C). Contributed by the high‐quality SnO2 layer prepared at low temperature, a high power conversion efficiency over 22% for flexible perovskite solar cells is also achieved. [ABSTRACT FROM AUTHOR]

Solvent additive can be used to regulate active layer morphology and improve photovoltaic performance of organic solar cells (OSCs). Herein, the PM6:Y6:PC71BM ternary bulk heterojunction OSCs are prepared by introducing 1,8‐diiodooctane (DIO) and 1‐chloronaphthalene (CN) as binary additives. On the basis of optimizing the photovoltaic performance with CN additive, the addition of trace amounts of DIO additive further improves the molecular packing of active layer and induces Y6:PC71BM acceptor on the surface of active layer. With the optimized active layer morphology, the CN and DIO binary additives restrict carrier recombination and improve charge transport efficiently, and the prepared PM6:Y6:PC71BM ternary OSCs with binary additives demonstrate a high short‐circuit current density of 27.15 mA cm−2 and a fill factor of 76.79%, and yield an improved power conversion efficiency of 17.53%, which is higher than that of devices without additives (16.50%) and with DIO (16.79%) or CN additive (17.21%). Binary solvent additives engineering provides an effective strategy to finely regulate active morphology and boost photovoltaic performance of ternary OSCs. [ABSTRACT FROM AUTHOR]

Developing new polymerized small molecular acceptor (PSMA) is pivotal for improving the performance of all‐polymer solar cells. On the basis of this newly developed CH‐series small molecule acceptors, two PSMAs are reported herein (namely PZC16 and PZC17, respectively). To reduce the molecular torsion caused by the traditional aromatic π‐bridges, non‐aromatic conjugated units (ethynyl for PZC16 and vinylene for PZC17) are adopted as the linkers and their effect on the photo‐physical properties as well as the device performance are systematically investigated. Both polymer acceptors exhibit co‐planar molecular conformation, along with broad absorption ranges and suitable energy levels. In comparison with the PM6:PZC16 film, the PM6:PZC17 film exhibits more uniform phase separation in morphology with a distinct bi‐continuous network and better crystallinity. The PM6:PZC17‐binary‐based devices exhibit a satisfactory PCE of 16.33%, significantly higher than 9.22% of the PZC16‐based devices. Impressively, PM6:PZC17‐based large area device (ca. 1 cm2) achieves an excellent PCE of 15.14%, which is among the top performance for reported all‐polymer solar cells (all‐PSCs). [ABSTRACT FROM AUTHOR]

Organic solar cells (OSCs) are a promising low‐cost thin‐film photovoltaic technology while the fabrication of transparent conductive oxide (TCO) and metal electrodes still remains a factor that hinders the scaling‐up and commercialization of OSCs. Carbon‐based materials are regarded as potential alternatives due to their excellent properties, such as low cost, solution processibility, high conductance, and good chemical stability. In this mini‐review, the recent progress of carbon‐based materials such as graphite, carbon nanosheets, graphene, and carbon nanotubes to replace the TCO and metal electrodes of OSCs is surveyed. The preparation methods of different carbon‐based materials are also discussed. Based on current progress, we summarize the outlooks and challenges of carbon‐based electrodes. We anticipate this mini‐review will inspire more research efforts to develop high‐performance and OSC‐matched carbon materials for more efficient and stable carbon‐electrode‐based OSCs. [ABSTRACT FROM AUTHOR]

A group of regioregular polymer acceptors is synthesized by polymerizing Y6 moieties with different linker units including thiophene, vinylene, 2,2'‐bithiophene, and thieno[3,2‐b]thiophene, and their optoelectrical properties and photovoltaic performances are studied systematically. It is found that the linker units have significant impacts on the backbone planarity, conjugation, and hence optoelectrical properties of polymer acceptors. The vinylene‐based PYF‐V‐o polymer shows a smaller dihedral angle between the end groups and vinylene units and a more rigid polymer backbone, thus affording bathochromic absorption and better electron‐transporting capacity. As a result, the PM6:PYF‐V‐o based all‐polymer solar cells (all‐PSCs) are able to achieve the highest power conversion efficiency of 16.4% with an unprecedented small voltage loss of 0.49 V. Moreover, the PM6:PYF‐V‐o blend exhibits good resistance to environmental stressors and the air‐processed PM6:PYF‐V‐o cells can still maintain a high efficiency of 16.1%, which is the best air‐processed all‐PSC efficiency reported to date. This study provides the structural‐property guidance that can be used to facilitate the development of polymer acceptors for all‐PSCs. [ABSTRACT FROM AUTHOR]

Recently, the strategy of polymerized small‐molecule acceptors (PSMAs) has attracted extensive attention for applications in all‐polymer solar cells (all‐PSCs). Although side‐chain engineering is considered as a simple and effective strategy for manipulating polymer properties, the corresponding effect on photovoltaic performance of PSMAs in all‐PSCs has not been systemically investigated. Herein, a series of PSMAs based on the benzotriazole (BTz)‐core fused SMAs with different N‐alkyl chains including branched 2‐butyloctyl, linear n‐octyl, and methyl on the BTz unit, namely PZT‐C12, PZT‐C8, and PZT‐C1, respectively, is presented. Comparative studies show that the size of alkyl chains has a significant impact on the solid‐state behavior of PZT polymers, which in turn affects their light absorption and charge transporting capacities, and subsequently the all‐PSC performances. When combining with the polymer donor PBDB‐T, PZT‐C1 affords a champion power conversion efficiency of 14.9%, compared to 13.1% of PZT‐C12, and 13.8% of PZT‐C8 in the resultant all‐PSCs, mainly benefiting from its better crystallinity and the more favorable blend morphology. This work emphasizes the importance of optimizing side‐chain substituents on PSMAs for improving the device efficiency of all‐PSCs. [ABSTRACT FROM AUTHOR]

A dataset containing 599 data points from 146 publications on 2D/3D perovskite solar cells is analyzed using machine learning. The predictive models are developed for power conversion efficiency (PCE) using eXtreme Gradient Boosting regression, random forest regression and artificial neural networks while association rule mining is used to analyze the stability data to identify the descriptors leading to high stability 2D/3D cells. A predictive model is also developed for the bandgap to predict the missing values in the dataset for the use in PCE predictions. Models for both bandgap and PCE predictions are quite successful. The thickness of inorganic layer (n), radius of anion (Rx), and 2D cation (Rm) are found to be the most important descriptors for bandgap predictions; n and Rm, together with the bandgap, are found to be deterministic for PCE in regular cells while the bandgap, n, and conduction band energy of hole transport layer are the most influential descriptors in inverted structures. Association rule mining analysis for the stability indicates that the cells with layered perovskite structures are more stable while the 2D and 3D cations leading to the most stable cells are found to be butylammonium and formamidinium‐Cs mixed cation respectively. [ABSTRACT FROM AUTHOR]

All‐polymer solar cells (all‐PSCs) progressed tremendously due to recent advances in polymerized small molecule acceptors (PSMAs), and their power conversion efficiencies (PCEs) have exceeded 15 %. However, the practical applications of all‐PSCs are still restricted by a lack of PSMAs with a broad absorption, high electron mobility, low energy loss, and good batch‐to‐batch reproducibility. A multi‐selenophene‐containing PSMA, PFY‐3Se, was developed based on a selenophene‐fused SMA framework and a selenophene π‐spacer. Compared to its thiophene analogue PFY‐0Se, PFY‐3Se shows a ≈30 nm red‐shifted absorption, increased electron mobility, and improved intermolecular interaction. In all‐PSCs, PFY‐3Se achieved an impressive PCE of 15.1 % with both high short‐circuit current density of 23.6 mA cm−2 and high fill factor of 0.737, and a low energy loss, which are among the best values in all‐PSCs reported to date and much better than PFY‐0Se (PCE=13.0 %). Notably, PFY‐3Se maintains similarly good batch‐to‐batch properties for realizing reproducible device performance, which is the first reported and also very rare for the PSMAs. Moreover, the PFY‐3Se‐based all‐PSCs show low dependence of PCE on device area (0.045–1.0 cm2) and active layer thickness (110–250 nm), indicating the great potential toward practical applications. [ABSTRACT FROM AUTHOR]

Due to the impressive optoelectronic properties, metal–halide perovskites (MHPs) have drawn much attention in the field of next‐generation photovoltaics, and perovskite solar cells (PSCs) based on MHPs as light absorbers have reached a certified power conversion efficiency (PCE) of 25.5% in 2020. Despite the great progress, it is still challenging to fabricate high‐quality MHP films. Due to the "soft" ionic nature of MHPs, their polycrystalline films suffer from inevitable residual strain, which is found to not only be fatal to photovoltaic performance of PSCs, but also seriously accelerate the degradation of MHP film. As a result, understanding of strain in MHPs and the key role of strain engineering in improving the photovoltaic performance of PSCs have recently been extensively investigated. Herein, the recent progress of strain engineering in MHPs and their PSCs is systematically summarized. First, the origin of strain in MHPs and the impact of strain on the optoelectronic characteristics of MHPs are carefully discussed. Thereafter, the up‐to‐date studies focusing on strain engineering in PSCs are comprehensively reviewed. At last, the current challenges and future prospects in this field are highlighted. [ABSTRACT FROM AUTHOR]

The synthesis of a series of novel A-π-D-π-A oligomers bearing either electron-donating dithieno[3,2- b :2′,3′- d ]silole (DTS) or dithieno[3,2- b :2′,3′- d ]pyrrole (DTP) units linked through a bithiophene π-bridge with the electron-withdrawing methyldicyanovinyl (DCV) or N-ethylrhodanine (Rh) groups is described. In order to evaluate the effects of different donor-acceptor combinations on various physical properties of the oligomers they are comprehensively studied by UV–Vis spectroscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and cyclic voltammetry (CV). Replacing the DTS by DTP as well as the DCV by Rh leads to increasing of HOMO energy levels and slight decreasing of LUMO energy levels, respectively. The DTP-based oligomers have a red shift in absorption spectra and an increased solubility as compared to the DTS-based analogs. Replacing the acceptor DCV unit by Rh also results in significantly higher solubility, but the Rh-based oligomers exhibit weaker intermolecular interactions, poorer optical absorption of sun light as well as lower charge carrier mobility in blends. Altogether, the structural improvement of the DTS-DCV and DTP-DCV blends upon annealing correlates well with the observed photovoltaic performances in organic solar cells. These results give more insight how to fine-tune and predict physical properties and photovoltaic performance of small A-π-D-π-A molecules having different donor-acceptor combinations in their chemical structures and thus providing a molecular design guideline for the next generation of high-performance photovoltaic materials. [ABSTRACT FROM AUTHOR]

• A terpolymer PF1 was developed by incorporating fluorinated BFT into PM6 backbone. • Introducting BFT can effectively tailor the molecular aggregation properties. • The PF1:Y6-based OSCs achieved a power conversion efficiency of up to 17.3%. Regulating molecular aggregation state via chemical modification of photovoltaic materials to optimize the blend morphology is an effective and challenging strategy to improve the photovoltaic performance of organic solar cells (OSCs). In this work, we demonstrate a random terpolymerization strategy by incorporating 1,3-bis(5-bromo-4-fluorothiophen-2-yl)-5,7-bis(2-ethylhexyl)-4H,8H-benzo[1,2-c:4,5-c']bisthiophene-4,8-dione (BFT, 30 mol%) unit with fluorinated π-bridges into the molecular backbone of PM6 and develop a terpolymer PF1. Benefiting from the strong electronegativity of fluorine atom and noncovalent interaction of F---S, the energy levels, molecular ordering, and aggregation properties of the polymer donors are precisely regulated. Notably, in the active layer film based on PF1: Y6, the π-π stacking distance can reduce to 3.51 Å, which is significantly smaller than that of PM6:Y6 (3.65 Å) and boosts the effective exciton dissociation and charge transport, thereby effectively optimize the photovoltaic properties of the related devices. As a result, the PF1:Y6-based OSCs achieved a power conversion efficiency (PCE) of up to 17.3%, which is much higher than that of the controlled OSCs based on PM6:Y6 (PCE = 16.2%). These results demonstrate high-efficiency OSCs enabled by regulating molecular aggregation via terpolymerization strategy. [ABSTRACT FROM AUTHOR]

This article explores the effect of bimetallic plasmonic nanocomposites in the solar absorber layers of thin-film organic solar cells (TFOSCs) for possible improvement in harvesting solar energy. To achieve this goal, a new nanocomposite composed of Nickel and Zinc (Ni: Zn) was successfully synthesized by the use of a chemical reduction processes. The effect of bimetallic nanocomposites was studied using a photoactive medium, which comprises of poly-(3-hexylthiophene) (P3HT) [6,6]-phenyl C61 butyric acid methyl ester (PC61BM) blend and doped with Ni:Zn at different concentrations. Consequently, an improved power conversion efficiency value up to 4.78% was found at 1% Ni:Zn bimetallic concentration by weight compared to reference solar cell. This is a clear indication of the influence of Ni:Zn bimetallic nanoparticles on the performance of TFOSC. These effects have been realized by the occurrence of local surface plasmon resonance (LSPR) phenomenon caused by Ni: Zn nanoparticles in polymer medium. • Bimetallic metal nanocomposite is used to improve photons harvesting in organic solar cell. • Power conversion efficiency of OSC has improved by over 80% from LSPR effect. • Ni:Zn nanocomposite is environmentally stable for roll to roll device fabrication. [ABSTRACT FROM AUTHOR]