Molecular-Device Co-Engineering of Ultra-Low Dark Current SWIR Organic Photodetectors for High-Quality Blood-Pressure Monitoring and Optical Communication.

The limited noise-responsivity balance in Short-wave infrared (SWIR) organic photodetectors (OPDs) restricts their biomedical and optoelectronic applications. In this study, this challenge is addressed through molecular-device co-engineering by designing two fluorinated narrow-bandgap non-fullerene acceptors (BTT-DTPn and BTT-DTPn-2F) coupled with solvent vapor annealing (SVA), achieving low noise and high detectivity in SWIR OPDs. The optimized devices based on BTT-DTPn-2F, which features enhance π-π stacking due to terminal fluorination, extend its absorption capability to 1300 nm.

Fully non-fused electron acceptor solar cells with 18% efficiency via a synergistic peripheral substituent strategy.

Toward commercialization of organic solar cells (OSCs), photoactive materials that enable high efficiency yet possess low cost should be developed. Fully non-fused ring electron acceptors (FNEAs) that extend the conjugated skeleton with carbon-carbon (C-C) single bonds solely have lower synthetic costs than their fused-ring counterparts. However, the power conversion efficiencies (PCEs) of FNEAs are lagging due to low acceptor crystallinity and difficulty in the formation of fibrillary bi-continuous interpenetrating network morphology.

Revealing the Effect of the Side Chain on the Adsorption Configuration of the Asymmetric Interface Molecule (PFN-Br) on the Acceptor (Y6) Interface.

The side chains of the interface layer materials of organic solar cells play an essential role in promoting dissolution, self-assembly, and energy level regulation. Still, the formation mechanism of these theories needs to be further studied. Theoretical calculation methods can predict and analyze the self-assembly process.

High-Performance Inverted Organic Solar Cells with MXene-Based Interfacial Engineering.

Inverted organic solar cells (OSCs) offer superior operational stability for practical applications, yet their power conversion efficiencies (PCE) lag behind those of conventional devices. This shortfall is primarily due to an excessive downshift in the electron affinity of nonfullerene acceptors, which hinders efficient charge extraction. Here, we introduce an MXene interlayer (TiCOH) to simultaneously optimize the energetic landscape at the ZnO/active layer interface and passivate ZnO surface defects.

Aggregation Optimization of Cathode Interlayer via Incorporating Cellulose Enables High-Performance Organic Solar Cells.

Regulating aggregation and molecular packing of small-molecule cathode interlayer (CIL) materials is a significant but imperceptible issue in the development of high-performance organic solar cells (OSCs). For the celebrity PDINN small molecule, the strong aggregation tendency of the perylene diimide molecular backbone leads to excessive crystallinity when films form, ultimately affecting the morphology and charge transport ability of the films. Herein, we address this issue by developing a hydroxyl-induced anti-aggregation strategy by introducing a suitable amount of hydroxypropyl cellulose (HPC) into the solution of PDINN, and a careful balance is achieved between the film-forming quality and the aggregation of the material.

Platinum Compound on Gold-Magnesia Hybrid Structure: A Theoretical Investigation on Adsorption, Hydrolysis, and Interaction with DNA Purine Bases.

Cisplatin-based platinum compounds are important clinical chemotherapeutic agents that participate in most tumor chemotherapy regimens. Through density-functional theory calculations, the formation and stability of the inorganic oxide carrier, the mechanisms of the hydrolysis reaction of the activated platinum compound, and its binding mechanism with DNA bases can be studied. The higher the oxidation state of Pt (II to IV), the more electrons transfer from the magnesia-gold composite material to the platinum compound.

Environmental remediation approaches by nanoscale zero valent iron (nZVI) based on its reductivity: a review.

The fast rise of organic and metallic pollution has brought significant risks to human health and the ecological environment. Consequently, the remediation of wastewater is in extremely urgent demand and has received increasing attention. Nanoscale zero valent iron (nZVI) possesses a high specific surface area and distinctive reactive interfaces, which offer plentiful active sites for the reduction, oxidation, and adsorption of contaminants.

Beyond Conventional Enhancements: Self-Organization of a Buffer Material on Tin Oxide as a Game-Changer for Improving the Performance of Inverted Organic Solar Cells.

Inverted organic solar cells (OSCs) have garnered significant interest due to their remarkable stability. In this study, the efficiency and stability of inverted OSCs are enhanced via the in situ self-organization (SO) of an interfacial modification material Phen-NaDPO onto tin oxide (SnO). During the device fabrication, Phen-NaDPO is spin-coated with the active materials all together on SnO.

Processing the Interlayer and Optimizing the Active Layer by One-Step Dissolution Compensation in Organic Solar Cells.

Optimized morphology of the active layer and electrode interface is critical for obtaining high-performance organic solar cells. However, achieving this typically involves a multifaceted, sequential process that renders outcomes unpredictable. Here, by exploiting the dissolution compensation, we propose a one-step method that integrates interlayer fabrication and a controllable morphology optimization.

Ni-CoSe heterojunction coated by N-doped carbon for modified separators of high-performance Li-sulfur batteries.

Functional separators modified by transition metal compounds have been proven to be effective in suppressing the shuttle effect of polysulfides and accelerating sluggish electrode dynamics in lithium-sulfur batteries (LSBs). However, the behaviors of heterojunctions composed of transition metals and their compounds in LSBs are still rarely studied. Herein, we report a novel Ni-CoSe heterostructure coated with nitrogen-doped carbon.

Revealing the AcOH-Induced Dissolution Mechanism of Alcohol-Soluble Interlayers.

Water/alcohol-soluble cathode interlayers are widely utilized in organic electronic devices. However, the mechanism by which acetic acid (AcOH) facilitates the solubility of neutral cathode interlayers in water/alcohol remains unclear. This paper focuses on the AcOH-induced dissolution mechanism of neutral cathode interlayer materials and establishes quantitative relationships for chemical reactions.

Chemisorption-Induced Robust and Homogeneous Tungsten Disulfide Interlayer Enables Stable PEDOT-Free Organic Solar Cells with Over 19% Efficiency.

Construction of a high-quality charge transport layer (CTL) with intimate contact with the substrate via tailored interface engineering is crucial to increase the overall charge transfer kinetics and stability for a bulk-heterojunction (BHJ) organic solar cell (OSC). Here, we demonstrate a surface chemistry strategy to achieve a homogeneous composite hole transport layer (C-HTL) with robust substrate contact by self-assembling two-dimensional tungsten disulfide (WS) nanosheets on a thin molybdenum oxide (MoO) film-evaporated indium tin oxide (ITO) substrate. It is found that over such a well-defined C-HTL, WS is homogeneously tethered on the ITO/MoO substrate stemming from the strong electronic coupling interaction between the building blocks, which enables a favorable interfacial configuration in terms of uniformity.

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.

An Anisotropic Hydrogel by Programmable Ionic Crosslinking for Sequential Two-Stage Actuation under Single Stimulus.

As one of the most important anisotropic intelligent materials, bi-layer stimuli-responsive actuating hydrogels have proven their wide potential in soft robots, artificial muscles, biosensors, and drug delivery. However, they can commonly provide a simple one-actuating process under one external stimulus, which severely limits their further application. Herein, we have developed a new anisotropic hydrogel actuator by local ionic crosslinking on the poly(acrylic acid) (PAA) hydrogel layer of the bi-layer hydrogel for sequential two-stage bending under a single stimulus.

Graphene oxide as a multi-functional additive for compatilizer, enhancer, and barrier in ethylene vinyl alcohol copolymer/aramid pulp composites.

To improve the thermal, mechanical, and barrier properties of ethylene vinyl alcohol copolymer (EVOH)/aramid pulp (AP), graphene oxide (GO) was used as a compatilizer, enhancer, and barrier to fabricate EVOH-based composites. The results showed that graphene oxide serves as an ideal compatilizer to reinforce the interfacial action between the EVOH matrix and aramid pulp. The EVOH/AP/GO composite presented the best combination of thermal stability, tensile strength, oxygen barrier, and heat deformation temperature by adding only 1 wt% graphene oxide, compared to those of pure EVOH.

Recent Advances in Halide Perovskite Resistive Switching Memory Devices: A Transformation from Lead-Based to Lead-Free Perovskites.

Due to their remarkable electrical and light absorption characteristics, hybrid organic-inorganic perovskites have recently gained popularity in several applications such as optoelectronics, lasers, and light-emitting diodes. Through this, there has recently been an increase in the use of halide perovskites (HPs) in resistive switching (RS) devices. However, lead-based (Pb-based) perovskites are notorious for being unstable and harmful to the environment.

Efficient Cathode Buffer Material Based on Dibenzothiophene-,-dioxide for Both Conventional and Inverted Organic Solar Cells.

A novel conjugated molecule (PBSON) based on a main chain composed of bis(dibenzothiophene-,-dioxide) fused cyclopentadiene and side chains containing amino groups is presented as an efficient cathode buffer material (CBM) for organic solar cells (OSCs). PBSON showed a deep highest occupied molecular orbital (HOMO) energy level of -6.01 eV, which was beneficial for building hole-blocking layers at the cathodes of OSCs.

Wide Bandgap Conjugated Polymers Based on Difluorobenzoxadiazole for Efficient Non-Fullerene Organic Solar Cells.

Wide bandgap polymers with a donor-acceptor alternating structure play a key role in constructing high-efficiency organic solar cells (OSCs). However, only a handful of high-performance polymers are available owing to the limited choices of acceptor units. 5,6-Difluorobenzo[c][1,2,5]oxadiazole (ffBX) is a promising acceptor unit with high ionization potential, and can afford high charge carrier mobility and strong aggregation for the resulting polymers.

Origin of the Additive-Induced V Change in Non-Fullerene Organic Solar Cells.

Additives are often used to adjust the morphology of the active layer to improve the performance of organic solar cells (OSCs). Here, taking typical high-efficiency non-fullerene systems as examples, the effect of the additive on the device performance in non-fullerene OSCs is systematically investigated. Surprisingly, an unpresented V change is observed in the opposite direction of the two typical systems (PM6:Y6 and PTB7-Th: ITIC) appearing after the incorporation of the additive DIO, which can be affected by the morphological differences as indicated by the several morphological studies.

Accelerating charge transfer via nonconjugated polyelectrolyte interlayers toward efficient versatile photoredox catalysis.

One of the challenges for high-efficiency single-component-based photoredox catalysts is the low charge transfer and extraction due to the high recombination rate. Here, we demonstrate a strategy to precisely control the charge separation and transport efficiency of the catalytic host by introducing electron or hole extraction interlayers to improve the catalytic efficiency. We use simple and easily available non-conjugated polyelectrolytes (NCPs) (i.

High-quality WS film as a hole transport layer in high-efficiency non-fullerene organic solar cells.

Liquid-exfoliated 2D transition metal disulfides (TMDs) are potential substitutes for poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as hole transport layers (HTLs) in Organic Solar Cells (OSCs). Herein, high-yield and high-quality WS flake layers are prepared by comprehensively controlling the initial concentration, sonication processing time and centrifugal speed. The WS layers deposited on transparent indium tin oxide (ITO) without plasma treatment show higher uniformity and conductivity than that formed on ITO after plasma treatment.

Mechanism of the Alcohol-Soluble Ionic Organic Interlayer in Organic Solar Cells.

In this article combining density functional theory (DFT) calculations and corresponding experimental measurements, the adsorption behaviors and working mechanism of the alcohol-soluble ionic organic interlayer on different electrode substrates were studied. The results suggest that, when the ionic organic bipyridine salt interlayer (FPyBr) is adsorbed on the Ag surface, Br will break away from molecule chains and form new chemical bonds with the Ag substrate, as confirmed by both the X-ray photoelectron spectroscopy (XPS) study and DFT study for the first time. Charges are further found to transfer to the Ag substrate from the new interlayer molecular structure without Br, resulting in adsorption dipoles directed from Ag to the interlayer.

Molecular Engineering Enhances the Charge Carriers Transport in Wide Band-Gap Polymer Donors Based Polymer Solar Cells.

The novel and appropriate molecular design for polymer donors are playing an important role in realizing high-efficiency and high stable polymer solar cells (PSCs). In this work, four conjugated polymers (PIDT-O, PIDTT-O, PIDT-S and PIDTT-S) with indacenodithiophene (IDT) and indacenodithieno [3,2-b]thiophene (IDTT) as the donor units, and alkoxy-substituted benzoxadiazole and benzothiadiazole derivatives as the acceptor units have been designed and synthesized. Taking advantages of the molecular engineering on polymer backbones, these four polymers showed differently photophysical and photovoltaic properties.

Optimized Molecular Packing and Nonradiative Energy Loss Based on Terpolymer Methodology Combining Two Asymmetric Segments for High-Performance Polymer Solar Cells.

In this work, a random terpolymer methodology combining two electron-rich units, asymmetric thienobenzodithiophene (TBD) and thieno[2,3-]benzofuran segments, is systematically investigated. The synergetic effect is embodied on the molecular packing and nanophase when copolymerized with 1,3-bis(2-ethylhexyl)benzo[1,2-:4,5-']dithiophene-4,8-dione, producing an impressive power conversion efficiency (PCE) of 14.2% in IT-4F-based NF-PSCs, which outperformed the corresponding D-A copolymers.

Molecular Engineering on Bis(benzothiophene-,-dioxide)-Based Large-Band Gap Polymers for Interfacial Modifications in Polymer Solar Cells.

The development of effectively universal interfacial materials for both conventional and inverted polymer solar cells (PSCs) plays a very crucial role in achieving highly photovoltaic performance and feasible device engineering. In this study, two novel alcohol-soluble conjugated polymers (PBSON-P and PBSON-FEO) with bis(benzothiophene-,-dioxide)-fused aromatics (FBTO) as the core unit and amino as functional groups are synthesized. They are utilized as universal cathode interfacial layers for both conventional and inverted PSCs simultaneously.