Nanoscale Balance of Energy Loss and Quantum Efficiency for High-Efficiency Polythiophene-Based Organic Solar Cells.

Polythiophene donors offer scalable and cost-effective solutions for the organic photovoltaic industry. A thorough understanding of the structure-property-performance relationship is essential for advancing polythiophene-based organic solar cells (PTOSCs) with high power conversion efficiencies (PCEs). Herein, we develop two polythiophene donors─PTTz-CN and PTTz-CN(T2)─to verify the energy loss-quantum efficiency relationship.

CF-Functionalized Side Chains in Nonfullerene Acceptors Promote Electrostatic Interactions for Highly Efficient Organic Solar Cells.

The advent of next-generation nonfullerene acceptors (NFAs) has propelled major advances in organic solar cells (OSCs). Here we report an NFA design incorporating CF-terminated side chains having varying -(CH)-CF linker lengths ( = 1, 2, and 3) which introduce new intermolecular interactions, hence strong modulation of the photovoltaic response. We report a systematic comparison and contrast characterization of this NFA series with a comprehensive set of chemical/physical techniques versus the heavily studied third-generation NFA, Y6, revealing distinctive and beneficial properties of this new NFA series.

Modulating Aggregation Behavior by Ternary Strategies for Efficient and Stable Thick-Film Organic Solar Cells.

Functional third components targeted to improve a specific property of organic solar cells is an effective strategy. However, introducing a third component to simultaneously improve efficiency and stability and achieve good performance in thick-film devices has rarely been reported. Herein, low diffusion third components IDCN and ID2CN are reported to achieve a power conversion efficiency (PCE) of 18.

Triadic Halobenzene Processing Additive Combined Advantages of Both Solvent and Solid Types for Efficient and Stable Organic Solar Cells.

Solvent additives with a high boiling point (BP) and low vapor pressure (VP) have formed a key handle for improving the performance of organic solar cells (OSCs). However, it is not always clear whether they remain in the active-layer film after deposition, which can negatively affect the reproducibility and stability of OSCs. In this study, an easily removable solvent additive (4-chloro-2-fluoroiodobenzene (CFIB)) with a low BP and high VP is introduced, behaving like volatile solid additives that can be completely removed during the device fabrication process.

Self-Powering Gas Sensing System Enabled by Double-Layer Triboelectric Nanogenerators Based on Poly(2-vinylpyridine)@BaTiO Core-Shell Hybrids with Superior Dispersibility and Uniformity.

Current core-shell hybrids used in diverse energy-related applications possess limited dispersibility and film uniformity that govern their overall performances. Herein, we showcase superdispersible core-shell hybrids (P2VP@BaTiO) composed of a poly(2-vinylpyridine) (P2VP) (5-20 wt %) and a barium titanate oxide (BaTiO), maximizing dielectric constants by forming the high-quality uniform films. The P2VP@BaTiO-based triboelectric nanogenerators (TENGs), especially the 10 wt % P2VP (P2VP@BaTiO)-based one, deliver significantly enhanced output performances compared to physically mixed P2VP/BaTiO counterparts.

Chalcogen Atoms Regulate the Organic Solar Cell Performance of B-N-Based Polymer Donors.

Donor polymers play a key role in the development of organic solar cells (OSCs). B-N-based polymer donors, as new types of materials, have attracted a lot of attention due to their special characteristics, such as high (T), small Δ, and easy synthesis, and they can be processed with real green solvents. However, the relationship between the chemical structure and device performance has not been systematically studied.

Sensitive Organic Photodetectors With Spectral Response up to 1.3 µm Using a Quinoidal Molecular Semiconductor.

Detecting short-wavelength infrared (SWIR) light has underpinned several emerging technologies. However, the development of highly sensitive organic photodetectors (OPDs) operating in the SWIR region is hindered by their poor external quantum efficiencies (EQEs) and high dark currents. Herein, the development of high-sensitivity SWIR-OPDs with an efficient photoelectric response extending up to 1.

An A-D-A'-D-A-Type Narrow Bandgap Electron Acceptor Based on Selenophene-Flanked Diketopyrrolopyrrole for Sensitive Near-Infrared Photodetection.

Near-infrared organic photodetectors possess great application potential in night vision, optical communication, and image sensing, but their development is limited by the lack of narrow bandgap organic semiconductors. A-D-A'-D-A-type molecules, featuring multiple intramolecular charge transfer effects, offer a robust framework for achieving near-infrared light absorption. Herein, we report a novel A-D-A'-D-A-type narrow bandgap electron acceptor named DPPSe-4Cl, which incorporates a selenophene-flanked diketopyrrolopyrrole (Se-DPP) unit as its central A' component.

Three-in-One Strategy Enables Single-Component Organic Solar Cells with Record Efficiency and High Stability.

Single-component organic solar cells (SCOSCs) with covalently bonding donor and acceptor are becoming increasingly attractive because of their superior stability over traditional multicomponent blend organic solar cells (OSCs). Nevertheless, the efficiency of SCOSCs is far behind the state-of-the-art multicomponent OSCs. Herein, by combination of the advantages of three-component and single-component devices, this work reports an innovative three-in-one strategy to boost the performance of SCOSCs.

Tethered Trimeric Small-molecular Acceptors through Aromatic-core Engineering for Highly Efficient and Thermally Stable Polymer Solar Cells.

Polymer solar cells (PSCs) rely on a blend of small molecular acceptors (SMAs) with polymer donors, where thermodynamic relaxation of SMAs poses critical concerns on operational stability. To tackle this issue, tethered SMAs, wherein multiple SMA-subunits are connected to the aromatic-core via flexible chains, are proposed. This design aims to an elevated glass transition temperature (T) for a dynamical control.

Acceptor-only oligomers with high coplanarity enable efficient and stable organic solar cells.

Acceptor-only oligomers are developed as guest components to construct oligomer-assisted active layers for high performance organic solar cells. Due to the high planarity and structural similarity with the host polymer donor, BDD-based acceptor-only oligomers formed an alloy phase with PM6 and optimized the phase morphology effectively, achieving a stable device displaying 18% efficiency.

High-Precision Tailored Polymer Molecular Weights for Specific Photovoltaic Applications through Ultrasound-Induced Simultaneous Physical and Chemical Events.

It is highly challenging to reproducibly prepare semiconducting polymers with targeted molecular weight tailored for next-generation photovoltaic applications. Once such an easily accessible methodology is established, which can not only contribute to overcome the current limitation of the statistically determined nature of semiconducting polymers, but also facilitate rapid incorporation into the broad synthetic chemists' toolbox. Here, we describe a simple yet robust ultrasonication-assisted Stille polymerization for accessing semiconducting polymers with high-precision tailored molecular weights (from low to ultrahigh molecular weight ranges) while mitigating their interbatch variations.

Multifunctional Acrylic Polymers with Enhanced Adhesive Property Serving as Excellent Edge Encapsulant for Stable Optoelectronic Devices.

Pendant groups in acrylic adhesive polymers (Ads) have a profound influence on adhesive and cohesive properties and additionally on encapsulant application. However, a systematic investigation to assess the impact of the pendant groups' length and bulkiness is rare, and there is not even a single report on applying Ads as interfacial adhesion promotors and encapsulation materials simultaneously. Herein, we have developed a series of multifunctional methacrylic polymers, namely, R--Ads, with varying pendant length and bulkiness (R = methyl (C1), ethyl (C2), propyl (C3), butyl (C4), pentyl (C5), hexyl (C6), isobutyl (iC4), and 2-ethylhexyl (2EH)).

Thickness Tolerance in Large-Area Organic Photovoltaics with Fluorine-Substituted Regioregular Conjugated Polymer.

Large areas and simple processing methods are necessary for the commercialization of organic photovoltaics (OPVs). However, the efficiency drop due to the variation in thickness of OPVs limits their large-scale applications. Regioregular polymers with good crystallinity and packing properties that exhibit high charge mobility and extraction ability can help overcome these limitations.

Octafluoronaphthalene as a thermal-annealing-free volatile solid additive enables high-performance organic solar cells.

A thermal annealing-free solid additive octafluoronaphthalene was developed for high-performance organic solar cells. In an additive-modified device, an impressive power conversion efficiency of 18.59% from 17.

Constructing High-Performance Ternary Device Using Analogous Polymer Donors.

Both ternary copolymerization and ternary blending are effective methods to fine-tune polymer structure and manipulate thin-film morphology to improve device performance. In this work, three D-A-A-A (D: donor, A: acceptor) terpolymer donors (FY1, FY2, and FY3) are synthesized by introducing BDD (1,3-bis(2-ethylhexyl)-5,7-di(thiophen-2-yl)benzo[1,2-c:4,5-c']dithiophene-4,8-dione) units into the D-A alternating copolymer PM6 backbone. Owing to the promoted conjugated planarity and excellent absorption of BDD, the obtained terpolymers display an extended absorption range and enhanced π-π stacking orientation, which is a promising third component in ternary device.

Electronic Configuration Tuning of Centrally Extended Non-Fullerene Acceptors Enabling Organic Solar Cells with Efficiency Approaching 19 .

In the molecular optimizations of non-fullerene acceptors (NFAs), extending the central core can tune the energy levels, reduce nonradiative energy loss, enhance the intramolecular (donor-acceptor and acceptor-acceptor) packing, facilitate the charge transport, and improve device performance. In this study, a new strategy was employed to synthesize acceptors featuring conjugation-extended electron-deficient cores. Among these, the acceptor CH-BBQ, embedded with benzobisthiadiazole, exhibited an optimal fibrillar network morphology, enhanced crystallinity, and improved charge generation/transport in blend films, leading to a power conversion efficiency of 18.

Conformational Locking Control of 2D Outer Side Chains via Fluorine Atom Positioning for Improving the Thermal Stability of Organic Solar Cells.

Alongside high power conversion efficiencies (PCEs), device stability, especially thermal issues, is another key factor for the successful commercialization of nonfullerene acceptor (NFA)-based organic solar cells (OSCs). Considering the significant effects of the side-chain engineering of NFAs on molecular packing and/or locking strongly associated with the thermal stability of OSCs, herein, we present two new isomeric NFAs with 4-fluoro- and 2-fluoro-substituted hexylphenyl two-dimensional (2D) outer side chains ( and , respectively). In contrast with the having a horizontal stretching conformation, exhibits a diagonal stretching conformation of the 2D outer side chains and a higher dipole moment, resulting in a huge difference in their crystalline/aggregation characteristics, i.

Regulating the Sequence Structure of Conjugated Block Copolymers Enables Large-Area Single-Component Organic Solar Cells with High Efficiency and Stability.

Single-component organic solar cells (SCOSCs) based on conjugated block copolymers (CBCs) by covalently bonding a polymer donor and polymer acceptor become more and more appealing due to the formation of a favorable and stable morphology. Unfortunately, a deep understanding of the effect of the assembly behavior caused by the sequence structure of CBCs on the device performance is still missing. Herein, from the aspect of manipulating the sequence length and distribution regularity of CBCs, we synthesized a series of new CBCs, namely D18(20)-b-PYIT, D18(40)-b-PYIT and D18(60)-b-PYIT by two-pot polymerization, and D18(40)-b-PYIT(r) by traditional one-pot method.

An electron acceptor with an intrinsic quinoidal core for bulk-heterojunction organic solar cells and photodetectors.

An electron acceptor based on a quinoidal dipyrrolopyrazinedione core was synthesized for organic solar cells and photodetectors. A power conversion efficiency of 6.7% and a specific detectivity of 4.

Naphthalene diimide-based random terpolymers with axisymmetric and asymmetric electron acceptors for controllable morphology and enhanced fill factors in all-polymer solar cells.

All-polymer solar cells (all-PSCs), based on p-type polymer donors and n-type acceptors as the active layer, offer exceptional promise because of excellent thermal stability, superior film formation, and good mechanical stress as a unique bulk heterojunction (BHJ) solar cell combination. Therefore, tuning the molecular composition between polymers is crucial for optimizing power conversion efficiency (PCE) in these all-PSC systems. In this study, we synthesized a series of naphthalene diimide (NDI)-based random terpolymers P(NDI-BDD10), P(NDI-TPD10), P(NDI-TT10), and P(NDI-2FQ10) with axisymmetric (BDD, TPD) and asymmetric (TT, 2FQ) electron acceptors.

Revealing the Molecular Weight Effect on Highly Efficient Polythiophene Solar Cells.

Polythiophenes (PTs) are promising electron donors in organic solar cells (OSCs) due to their simple structures and excellent synthetic scalability. Benefiting from the rational molecular design, the power conversion efficiency (PCE) of PT solar cells has been greatly improved. Herein, five batches of the champion PT (P5TCN-F25) with molecular weights ranging from 30 to 87 kg mol were prepared, and the effect of the molecular weight on the blend film morphology and photovoltaic performance of PT solar cells was systematically investigated.

Geometry design of tethered small-molecule acceptor enables highly stable and efficient polymer solar cells.

With the power conversion efficiency of binary polymer solar cells dramatically improved, the thermal stability of the small-molecule acceptors raised the main concerns on the device operating stability. Here, to address this issue, thiophene-dicarboxylate spacer tethered small-molecule acceptors are designed, and their molecular geometries are further regulated via the thiophene-core isomerism engineering, affording dimeric TDY-α with a 2, 5-substitution and TDY-β with 3, 4-substitution on the core. It shows that TDY-α processes a higher glass transition temperature, better crystallinity relative to its individual small-molecule acceptor segment and isomeric counterpart of TDY-β, and a more stable morphology with the polymer donor.

High-Performance Electrochemical and Photoelectrochemical Water Splitting at Neutral pH by Ir Nanocluster-Anchored CoFe-Layered Double Hydroxide Nanosheets.

Highly efficient electrocatalysts for the oxygen evolution reaction (OER) in neutral electrolytes are indispensable for practical electrochemical and photoelectrochemical water splitting technologies. However, there is a lack of good, neutral OER electrocatalysts because of the poor stability when H accumulates during the OER and slow OER kinetics at neutral pH. Herein, we report Ir species nanocluster-anchored, Co/Fe-layered double hydroxide (LDH) nanostructures in which the crystalline nature of LDH-restrained corrosion associated with H and the Ir species dramatically enhanced the OEC kinetics at neutral pH.