Organic solar cells (OSCs) fabricated under ambient air are essential for scalable and low-cost production, however, their power conversion efficiencies (PCEs) remain much lower than those of devices processed in nitrogen atmospheres. Herein, we introduce a solid additive, 3,5-dichloroiodobenzene (DCIB), to enable efficient air-processed OSCs with 65% relative humidity. DCIB improves molecular packing in the active layer, reducing energetic disorder and thereby enhancing exciton diffusion, charge transport, and suppressing recombination. Benefiting from compact molecular packing, DCIB-treated PM6:L8-BO-based OSC achieved an PCE of 19.53% under ambient-air processing, outperforming the 1,8-diiodooctane (DIO)-treated device with a PCE of 17.30%. Notably, the devices still delivered a high PCE of 18.30% at an active-layer thickness of 300 nm, indicating excellent thickness tolerance. The encapsulated DCIB-treated devices retained 95% of their initial efficiency after 300 h of continuous illumination under ambient air, whereas the DIO-treated devices retained only 35%. As a preliminary assessment of scalability, an unoptimized 120 cm2 module fabricated in air achieved a PCE of 11.60%. DCIB also demonstrated good universality, enabling D18:L8-BO-based devices to achieve a PCE of 20.32% under ambient air. These results demonstrate that DCIB is an effective solid additive for realizing high-performance thick-film OSCs under ambient-air processing.

The development of effective small-molecule acceptors (SMAs) processed by non-halogenated solvents has become crucial for realizing eco-friendly and high-performance transparent organic photovoltaics (TOPVs). In this study, a pentacyclic fused-ring ultra-narrow bandgap acceptor (BZ-OEG) was designed and synthesized, featuring a benzotriazole core modified with oligo(ethylene glycol) (OEG) side chains. BZ-OEG demonstrates favorable solubility in o-xylene, which enables the fabrication of binary organic photovoltaics (OPVs) based on PTB7-Th:BZ-OEG from an o-xylene solution, achieving a power conversion efficiency (PCE) of 11.7%. To further improve the device performance, PA-2Br was incorporated as a guest acceptor. Strong pi-pi stacking and halogen bonding interactions between PA-2Br and BZ-OEG optimized the light-harvesting capability and molecular packing of the blend film, forming an acceptor alloy phase that effectively suppressed voltage losses and improved charge carrier dynamics. As a result, the optimized opaque ternary device based on PTB7-Th:BZ-OEG:PA-2Br attained a PCE of 13.2%. Furthermore, TOPVs employing the same ternary system as the active layer achieved a PCE of 4.60% while maintaining an average visible transmittance (AVT) of 70.0%. This study presents a viable strategy for the fabrication of high-performance TOPVs processed from non-halogenated solvents.

Moisture in the air can harm the photovoltaic performance of organic photovoltaic (OPV) devices due to the serious charge recombination induced by moisture. The interface between the electron transport layer (ETL) and the top electrode is easily invaded by moisture since it is the outermost interlayer of the device. Here, we report an effective strategy to enhance the moisture resistance of the device by modifying the interface between the ETL of ZnO nanoparticles (ZnO NPs) and the electrode with a coordination interlayer. This strategy dramatically strengthens the adhesion between the ZnO NPs layer and the Ag electrode, thereby reducing the invasion of moisture at the interface and enhancing the device's stability in air. After introducing the coordination interlayer, the power conversion efficiency (PCE) of the unencapsulated devices increased substantially from 0.1% to 16.3% when measured under open-air conditions. Notably, the unencapsulated devices retained 85% and 56% of the initial PCE after 14 days and 1 year of storage in the air, respectively.

Developing ultra-narrow bandgap electron acceptors is an effective approach to achieving transparent organic photovoltaics (TOPVs). In this study, two phenazine based non-fullerene acceptors, namely PA-2H and PA-2Br, are synthesized by merging core bromination and extended conjugation. Applying extra ethylene double bonds as π bridge makes the absorption onsets of films red shift to 1021 and 1041 nm for PA-2H and PA-2Br, respectively. Single-crystal data illustrated that PA-2Br exhibits a tight and ordered 3D network packing with improved charge transport, different from the 2D step-like packing of PA-2H. Therefore, PA-2Br-based opaque organic photovoltaics achieves an excellent power conversion efficiency (PCE) of 13.7%. Notably, the TOPV attains a PCE of 4.60% with an average visible transmittance (AVT) of 70.2%, which exhibits promise in efficient TOPVs. This work demonstrates the importance of core bromination in the design of high-performance ultra-narrow bandgap electron acceptors and provides the opportunity to fabricate efficient TOPVs.

Artificial photoreceptor-based retinal prostheses are a therapeutic strategy for the treatment of retinal degenerative diseases. Currently, it is challenging to construct an artificial retinal prosthesis based on a biocompatible neural interface using simple methods to achieve efficient neuronal stimulation under low light intensity and simulate visual resolution. Here, we demonstrate an effective strategy to dramatically enhance the sensitivity and selectivity of neuronal stimulation by constructing an antibody-modified photovoltaic biointerface between artificial photoreceptor devices and neuronal cells. Neurons cultured on the antibody-modified photovoltaic biointerface can be successfully activated through light irradiation with a light intensity lower than 5 mW cm-2, which is dramatically lower than the required light intensity of 1-Sun conditions for traditional artificial retinal prostheses. Benefiting from the antibody-modified interface for specific targeting, an arrayed distribution of neurons was achieved on the biointerface with Au arrays. This study develops an artificial photoreceptor system for synergistic integration of guided cellular growth and enhanced neural photoactivation, proposing a potential method for retinal prostheses and visual restoration.

Organic solar cells (OSCs) have achieved power conversion efficiencies (PCEs) exceeding 20%, yet the transition from lab to market remains challenging. This study proposes a systematic molecular engineering paradigm for developing cost-effective polymer donors, exemplified by PPT-3, specifically engineered for semitransparent solar windows. Using simple monocyclic aromatic units, we simplified the synthesis, enabling scalable production from milligrams to 20 g. Opaque OSCs based on PPT-3 achieved PCEs exceeding 18%, with excellent batch-to-batch reproducibility across multiple scales, including three Stille batches (0.2-5.0 g) and four direct-arylation batches (0.2-20.0 g). Moreover, ambient blade-coated semitransparent modules achieved a record PCE of 6.69%, an average visible transmittance of 40.30%, and a light-utilization efficiency of 2.70% over a 120 cm2 active area. This work demonstrates the first scalable synthesis of highperformance polymers (PCE >18%) via a tin-free polymerization route, offering a transformative pathway for advancing OSCs from lab-scale research to commercial viability.

Photochromic transparent photovoltaic is a promising candidate for developing smart windows in the building-integrated photovoltaic field. However, most reported photochromic solar cells must employ liquid electrolyte in the device to achieve the photochromic function. Herein, solid-state photochromic semitransparent organic photovoltaics (ST-OPVs) based on a photochromic molecule with bisthienylethene (BTE) unit are reported. ST-OPVs show a transmittance change of up to 6.10% under light irradiation, demonstrating a power conversion efficiency (PCE) of 5.21% and an average visible transmission of over 50%. The coloration-decoloration process is reversible under UV irradiation and thermal annealing. After five coloration-decoloration cycles, the photochromic ST-OPVs can maintain 66.6% of the initial PCE. This work presents a promising application of photochromic molecules in ST-OPVs, providing a feasible strategy for photochromic photovoltaics.

Three-dimensional (3D) spatial light detection enables the localization and orientation estimation of light sources in space. Conventional approaches often rely on active systems, such as using structured light, which is complex, bulky, and computationally intensive. Here, we report a passive spatial light detection system based on vertically stacked transparent photodetector arrays. By capturing imaging differences across multiple transparent layers positioned at distinct imaging planes, the system reconstructs angular and positional information on incident light. The transparent nature of the photodetectors allows integration with other optical modules, such as hyperspectral cameras, enabling multidimensional light-field sensing within a compact footprint. This straightforward stacking architecture, combined with a lightweight image processing algorithm, offers a scalable route toward low-power, space-efficient multidimensional sensing platforms.

Ultrathin organic photovoltaics (OPVs) have great application prospects in the field of wearable electronics, such as electronic tattoos, electronic skins, etc. In this study, we report substrate-free ultrathin OPVs with a thickness of approximately 200 nm. The freestanding OPV devices achieve a power conversion efficiency of 11.6% and a power-per-weight ratio of 109.4 W g-1, with a weight of 1.06 g m-2. The ultrathin OPVs can self-adhere to various surfaces with complex and curved structures, ensuring excellent conformity. Notably, the ultrathin OPV devices demonstrate remarkable mechanical flexibility, maintaining 90% of their initial power conversion efficiency after 1000 compression-stretching cycles and are capable of bending to a radius of less than 2 μm. These attributes make ultrathin OPVs a crucial advancement in expanding the application landscape for wearable electronics and other special applications with ultraflexible and ultralight requests.

Reducing active layer thickness is an effective method to improve the average visible transmission (AVT) and color rendering index (CRI) of transparent organic photovoltaics (TOPVs). However, the high‐transparency TOPVs with ultrathin active layers often suffer from substantial charge recombination, resulting in low power conversion efficiency (PCE). Here, we report a ternary strategy of introducing a UV‐absorbing molecule (TPA‐TPD) into near‐infrared absorbing TOPVs, which can significantly suppress the charge recombination when reducing the thickness of the active layer in TOPVs. Due to its good miscibility and charge transfer properties with the receptors, the aggregation of the receptors was suppressed, and the active layer was preferentially oriented in face‐on orientation. The prepared TOPV exhibits an efficiency of 1.03% with a record AVT of 89% and a CRI of 98.1. This work provides a valuable reference for the fabrication of optoelectronic devices with ultrathin active layers.

The all-solution process is an essential technology for large-scale production and cost reduction of transparent organic photovoltaics (TOPVs). However, this process still involves the sequential deposition of a transport layer and a transparent electrode on the active layer, increasing the process complexity. In this work, we demonstrate a silver nanowires (AgNWs): PDINO dual-function transparent electrode that achieves the functions of electron transport and collection through a single coating step. The all-solution-processed TOPV with dual-function electrodes achieved a power conversion efficiency (PCE) of 13.2% and fill factor (FF) of 77.4%, comparable to the performance of the device prepared with the thermal-evaporation top electrode, and represents the highest PCE and FF reported to date for all-solution-processed TOPVs. Notably, the 12 cm2 semitransparent mini-module devices achieved an impressive PCE of up to 9.64% and high fill factor of 69.0% by using the AgNWs: PDINO dual-functional electrodes under open-air conditions. The study demonstrates the potential of using AgNWs: PDINO dual-function transparent electrodes as a simple and scalable method for fabricating efficient and all-solution-processed TOPVs.

While perylene diimide derivatives such as PDINN and PDINO have demonstrated excellent efficiency as electron transport layers (ETLs) in organic photovoltaic (OPV) devices, the parent compound PDIN exhibits limited solubility in methanol due to its extended conjugated aromatic structure, restricting its practical application. Herein, a sulfur-containing ETL, PDIN-SO, synthesized via a facile one-step process is reported by introducing sulfur dioxide (SO2) gas to PDIN. This straightforward synthetic approach yields a compound with exceptional methanol solubility, addressing a key limitation of conventional materials. OPV devices with PDIN-SO as the ETL demonstrated performance comparable to those utilizing established ETL materials, including PFN-Br and PDINO. Notably, PDIN-SO-based devices exhibited remarkable tolerance to variations in sulfur content, indicating robust processing versatility. When implemented with a PM6: BTP-eC9: L8-BO active layer, optimized devices achieved an impressive power conversion efficiency (PCE) of 18%. This work demonstrates that PDIN-SO, with its simplified synthesis pathway, excellent solubility, and outstanding device performance, represents a promising ETL material that can accelerate the development of high-efficiency, stable OPVs.

High-quality single-layer dispersions have long been a critical prerequisite for fabricating uniform monolayer coatings of two-dimensional (2D) materials, which unfortunately demand extensive processing steps such as iterative exfoliation and exhaustive purification. Here, using graphene oxide (GO) as the first prototypical 2D material, we demonstrate a "stick-and-tear" strategy to rapidly produce near-complete, precisely single-layer coatings on diverse substrates directly from crude GO suspensions, which contain heterogeneous structures and aggregates of various geometries and ionic impurities. In the "stick" step, only the soft, compliant components of the unpurified crude suspension (e.g., few- and single-layer sheets or loose aggregates) can conform to and strongly adhere to the substrate. During the subsequent "tear" step, excess layers, wrinkles, and overlapping regions are selectively removed by gentle sonication. It is demonstrated that the process works over a broad range of GO concentrations, solution pH values, and can tolerate salt concentrations well above the maximal levels of typical GO synthesis. Monolayer coatings on SiO2/Si, glass, indium-tin oxide (ITO)/glass, and curved metal surfaces have been demonstrated. As a proof-of-concept of potential uses, such precise monolayer coating of GO is demonstrated to be an effective hole-transport-layer on ITO for high-performance organic photovoltaic devices. The strategy's material-agnostic nature is further validated by producing dense monolayer coatings of Ti3C2Tx MXene directly from its crude suspensions. By leveraging inherent mechanical contrasts in 2D materials, this work establishes a rapid, scalable pathway to precise monolayer coatings, circumventing conventional purification bottlenecks and opening avenues for functional devices with diverse colloidal 2D materials.

With the advantages of low cost, high transparency and high conductivity, metal mesh electrodes are emerging as promising transparent electrodes in the electronics industry. However, due to the large spacing of the mesh, it is difficult to efficiently collect photogenerated carriers from the active layer, which makes metal mesh electrodes inapplicable to organic photovoltaic (OPV) devices. In this work, we report an ultrathin copper/silver (Cu/Ag) mesh transparent electrode with suitable mesh spacing by ultraviolet lithography technology. The mesh spacing and width can be fine-adjusted to tune the transparency and improve the charge collection efficiency. When the spacing was 5 μm and the width was 1 μm, the mesh electrode exhibited an average visible transmittance (AVT) of 85% with a sheet resistance (Rs) of ∼200 Ω/sq. Adopting this mesh electrode as the bottom transparent electrode, the ITO-free OPV was fabricated with a champion efficiency of 14.2%. Notably, the semitransparent device was also established with an efficiency of 8.3% and an AVT of 30.3% by using the ultrathin Cu/Ag mesh transparent electrode.

The spontaneous spreading (SS) process is one of the solution-processed technologies for preparing organic photovoltaics (OPVs). As a broadly used solvent in OPV preparation, chloroform is rarely applied in the SS process since the chloroform-based active layer solution generally forms a wrinkled film, which limits the performance of the devices. In this work, an SS process is developed with amphiphilic additives to prepare efficient OPVs using chloroform as the solvent. By adding amphiphilic additives into the chloroform solution, the interfacial tension between the chloroform solution and water can be tuned finely, and a uniform active layer film can be formed on the water surface. Adopting SS-PM6:Y6 film as the active layer, the SS-OPV is successfully prepared in open-air conditions, and the device performance is comparable to the device prepared by the spin-coating method. Notably, the OPV device using recycled SS-PM6:Y6 film is also demonstrated to present an efficiency of over 14%.

The spontaneous spreading (SS) process offers a unique solution-processed platform for fabricating organic photovoltaics (OPVs) under open-air conditions. Yet its development is hindered by limited strategies to achieve uniform film thickness and homogeneous phase morphology. In this work, an SS process is developed using the green solvent o-xylene and mediated by solid additives to regulate interfacial tension, enabling the formation of uniform SS-films on the water surface. The aromatic solid additive phenanthrene (PAT) extended the drying time of the wet film, effectively suppressed excessive acceptor aggregation, enhanced molecular packing order, and optimized phase-separated morphology for the SS-film. The OPV device with SS-film as the active layer achieved a champion efficiency of 16.4%. To the best of current knowledge, this is the first attempt to introduce solid additives in SS-processed OPVs, offering a versatile strategy to simultaneously adjust film-forming kinetics and phase morphology. This study presents a simple approach to fabricating solution OPVs with solution processability and reproducibility.

PEDOT:PSS is one of the best hole transport materials in organic photovoltaics (OPV). However, due to poor wettability, the aqueous PEDOT:PSS (a-PEDOT) is not applicable for inverted structured OPV as a hole transport layer (HTL) on top of the active layer. In this work, organic solvent-based PEDOT:PSS (o-PEDOT) with improved wettability was prepared by the solvent-replacement method through centrifugal ultrafiltration, dialysis membrane, and thermal evaporation. Adopting o-PEDOT as the HTL on the top surface of the active layer, the inverted OPVs were successfully prepared through a solution process. Importantly, due to good conductivity and suitable work function, the o-PEDOT can also act as the interconnection layer (ICL) in air-processed tandem OPV devices. The tandem device achieved a champion PCE of 15%, among the best reports of solution-processed homotandem OPV under open-air conditions. The flexible tandem OPV using o-PEDOT as an ICL was also demonstrated, with an efficiency of over 14%.

Transparent photovoltaic (TPV) devices have great potential to be applied as smart windows in construction and agriculture fields. TPVs with an average visible transmission (AVT) exceeding 50% are among the strong candidates to build lighting windows since the champion efficiency has already exceeded 10%. However, it is still a challenge in TPVs that semiconductors are generally expensive and transparency is difficult to further enhance, particularly for device AVT exceeding 70%. In this work, we develop a set of fullerene-based heterojunctions to harvest the light. By utilizing the low-cost fullerene as the light-absorbing material and combining it with the transparent electrode, the fabricated TPV device can achieve an AVT of 72.1% with a PCE exceeding 1%. Notably, the device with an AVT of 82% is also successfully demonstrated. This study provides an effective approach for building low-cost and efficient TPV devices.

Wavelength recognition is one of the important functions of photodetectors. However, wavelength recognition of the reported photodetectors generally depends on light intensity, which limits the practical applications. Here, a light intensity-independent wavelength recognition scheme based on vertically stacked transparent photodetectors is reported. By analyzing light intensity attenuation behavior in the multiple stacked photodetectors, the wavelength of incident light can be accurately determined. Due to the high transparency of the detectors, the multiple stacked detectors allow incident light to pass through. Meanwhile, since the attenuation coefficients at different wavelengths are attributed to the detector's absorption characteristics, the intensity of incident light and its wavelength can be determined by analyzing the attenuation coefficients measured through each stacked detector. Consistent wavelength values obtained at different light intensities verify the light intensity-independence of the multistacked detector system.

Bio-artificial photosynthetic systems can reduce CO2 into multicarbon compounds by simulating natural photosynthesis. Here, inspired by organic photovoltaic structures, we demonstrate a bio-artificial photosynthetic system based on the hybridization of polymer semiconductor films and bacteria. The study suggests that the polymer-based semiconductor film can efficiently drive the non-photosynthetic bacteria to convert CO2 to acetate. By systematically characterizing the charge transport behavior of the bio-artificial photosynthetic system, the bulk-heterojunction structure and charge transport layers are proven to enhance the system performance markedly. The scalable floating artificial bio-leaf system can produce acetate to gram scale in a week. Notably, the semiconductor film is easy to recycle and maintains stable performance, showing good sustainable production capability of the system. A quasi-solid-state artificial bio-leaf is successfully prepared using agar to simulate the morphology and function of natural leaves. Last, the acetate production converted from CO2 was used to grow yeast for food production, thus achieving a complete simulation of natural photosynthesis.