Chemically Enhanced Raman Scattering Enabled by Organic Semiconductor Molecules with Deep Lowest Unoccupied Molecular Orbitals.

Organic semiconductor materials (OSMs) have emerged as innovative platforms for surface-enhanced Raman scattering (SERS). For now, SERS activity has been established in only a few materials like thiophene-based derivatives, and the potential of the broader OSM library is largely untapped. Systematic exploration of energy level alignment between analytes and the OSM substrates is highly desirable for further material screening and optimization.

Spin-Orbital Ordering Effects of Light Emission in Organic-Inorganic Hybrid Metal Halide Perovskites.

Organic-inorganic hybrid metal halide perovskites carrying strong spin-orbital coupling (SOC) have demonstrated remarkable light-emitting properties in spontaneous emission, amplified spontaneous emission (ASE), and circularly-polarized luminescence (CPL). Experimental studies have shown that SOC plays an important role in controlling the light-emitting properties in such hybrid perovskites. Here, the SOC consists of both orbital (L) and spin (S) momentum, leading to the formation of J (= L + S) excitons intrinsically involving orbital and spin momentum.

Perylene Bisimide-Functionalized Triphenylmethyl Radicals Showing High Stability and Reversible Electrochemical Redox Properties.

This study presents a series of triphenylmethyl monoradicals incorporating varying numbers of peripheral perylene bisimide (PBI) substituents (1PBI-TTM⋅, 2PBI-TTM⋅ and 3PBI-TTM⋅). The incorporation of electron-withdrawing PBI substituents significantly enhances the stability of these carbon radicals, enabling them to display exceptional electrochemical redox reversibility. Notably, the electronic interplay between the PBI substituents and the central triphenylmethyl core facilitates unique and reversible multi-step redox reactions.

Achieving Ultra-Narrow-Band Deep-Red Electroluminescence By a Soliton-type Dye Squaraine.

Due to the soliton-like electronic structural characteristics, cyanine dyes typically exhibit spectral behaviors such as large molar extinction coefficients, narrow spectra, and high fluorescence efficiency. However, their extensive applications as emitters in electroluminescence are largely ignored due to their serious emission quenching in the aggregation state. Herein, it is reported a squaraine dye (a type of cyanine) SQPhEt.

Lighting Up Nonemissive Azobenzene Derivatives by Pressure.

Pressure-induced emission (PIE) is a compelling phenomenon that can activate luminescence within nonemissive materials. However, PIE in nonemissive organic materials has never been achieved. Herein, we present the first observation of PIE in an organic system, specifically within nonemissive azobenzene derivatives.

Band-like transport in solution-processed perylene diimide dianion films with high Hall mobility.

It is crucial to prepare high-mobility organic polycrystalline film through solution processing. However, the delocalized carrier transport of polycrystalline films in organic semiconductors has rarely been investigated through Hall-effect measurement. This study presents a strategy for building strong intermolecular interactions to fabricate solution-crystallized p-type perylene diimide (PDI) dianion films with a closer intermolecular π-π stacking distance of 3.

Influence of Interaction between Electrolyte with Side-Chain Free Conjugated Polymer on the Performance of Organic Electrochemical Transistors.

Organic electrochemical transistors (OECTs) offer significant advantages in electrophysiological applications, primarily due to their ability to facilitate ionic-to-electronic conversion and establish a direct interface with the surrounding aqueous environments by using organic mixed ionic-electronic conductors. This study employs a side-chain free n-type conducting polymer, poly(benzodifurandione) (PBFDO), as the channel material in OECTs to scrutinize the interplay between various ion concentrations in electrolytes and the conjugated polymer and to assess their subsequent impact on device performance. Our findings reveal that PBFDO-based OECTs demonstrate superior transfer characteristics, attributed to their high conductivity and remarkable stability in aqueous solutions.

Nanoarchitectonics on Electrosynthesis and Assembly of Conjugated Metallopolymers.

In contrast to edge-on and face-on orientations, end-on uniaxial conjugated polymers have the theoretical possibility of providing a macroscopic crystalline film. However, their fabrication is insurmountable due to sluggishly thermodynamic equilibrium states. Herein, we report the programmatic pathway to fabricate nanoarchitectonics on end-on uniaxial conjugated metallopolymers by surface-initiated simultaneous electrosynthesis and assembly.

A theoretical study on π-stacking and ferromagnetism of the perylene diimide radical anion dimer and tetramer.

Ferromagnetism is rare in pure organic materials. Recently, the perylene diimide radical anion (PDI) salt prepared through solvothermal reduction by hydrazine hydrate has shown room-temperature ferromagnetism in our work [Jiang , , 2022, , 2108103]. Based on this, herein we conduct a theoretical study based on density functional theory (DFT) to reveal the stacked geometries between two NHPDI monomers for low-spin (LS) and high-spin (HS) states and their magnetic exchange interactions () using Yamaguchi's approximate spin projection.

Extremely Stable Perylene Bisimide-Bridged Regioisomeric Diradicals and Their Redox Properties.

Excellent stability is an essential premise for organic diradicals to be used in organic electronic and spintronic devices. We have attached two tris(2,4,6-trichlorophenyl)methyl (TTM) radical building blocks to the two sides of perylene bisimide (PBI) bridges and obtained two regioisomeric diradicals (1,6-TTM-PBI and 1,7-TTM-PBI). Both of the isomers show super stability rather than the monomeric TTM under ambient conditions, due to the increased conjugation and the electron-withdrawing effects of the PBI bridges.

Chemical doping of unsubstituted perylene diimide to create radical anions with enhanced stability and tunable photothermal conversion efficiency.

N-doping of perylene diimides (PDIs) to create stable radical anions is significant for harvesting photothermal energy due to their intensive absorption in the near-infrared (NIR) region and non-fluorescence. In this work, a facile and straightforward method has been developed to control the doping of perylene diimide to create radical anions using organic polymer polyethyleneimine (PEI) as a dopant. It was demonstrated that PEI is an effective polymer-reducing agent for the n-doping of PDI toward the controllable generation of radical anions.

A Nitroxide Radical Conjugated Polymer as an Additive to Reduce Nonradiative Energy Loss in Organic Solar Cells.

Nonfullerene-acceptor-based organic solar cells (NFA-OSCs) are now set off to the 20% power conversion efficiency milestone. To achieve this, minimizing all loss channels, including nonradiative photovoltage losses, seems a necessity. Nonradiative recombination, to a great extent, is known to be an inherent material property due to vibrationally induced decay of charge-transfer (CT) states or their back electron transfer to the triplet excitons.

Correction: lncRNA PSMB8-AS1 promotes colorectal cancer progression through sponging miR-1299 to upregulate ADAMTS5.

This corrects the article DOI: 10.4149/neo_2022_220111N42.

The Multiplicity of π-π Interactions of Fused-Ring Electron Acceptor Polymorphs on the Exciton Migration and Charge Transport.

Efficient long-range exciton migration and charge transport are the key parameters for organic photovoltaic materials, which strongly depend on the molecular stacking modes. Herein, we extracted the stacked structures of the archetype fused-ring electron acceptor molecule, ITIC, based on the information on four polymorphic crystals and investigated the relationship between molecular stacking modes and exciton migration/charge transport properties through the intermolecular Coulomb coupling and charge transfer integral calculation. Experimentally, the thin film texture is crystallized through a post-annealing treatment through grazing-incidence wide-angle X-ray scattering (GIWAXS) measurements, which lead to the enhanced exciton migration through exciton-exciton annihilation in the femtosecond transient absorption (fs-TA) measurements.

Sulfone-Embedded Heterocyclic Narrowband Emitters with Strengthened Molecular Rigidity and Suppressed High-Frequency Vibronic Coupling.

Sulfone-embedded heterocyclics are of great interest in organic light-emitting diodes (OLEDs), however, exploring highly efficient narrowband emitters based on sulfone-embedded heterocyclics remains challenging. Herein, five emitters with different sulfur valence state and molecular rigidity, namely tP, tCPD, 2tCPD, tPD and tPT, are thoroughly analysed. With restricted twisting of flexible peripheral phenyl by strengthening molecular rigidity, molecular emission spectra can be enormously narrowed.

The Causal Effect of Reproductive Factors on Breast Cancer: A Two-Sample Mendelian Randomization Study.

Several studies have shown that female reproductive factors are associated with breast cancer (BC), but the results differ. We conducted two-sample MR in the present work. The raw data applied in the MR study were all from the Genome-wide association study (GWAS) database.

High-efficiency blue-emission crystalline organic light-emitting diodes sensitized by "hot exciton" fluorescent nanoaggregates.

Sensitizing fluorescent materials is an effective way to maximally use excitons and obtain high-efficiency blue organic light-emitting diodes (OLEDs). However, it is a persistent challenge for present amorphous thin-film OLEDs to improve photon emission under low driving voltage, severely impeding the development of OLED technology. Here, we propose a novel OLED architecture consisting of a crystalline host matrix (CHM) and embedded "hot exciton" nanoaggregates (HENAs), which effectively sensitize blue dopant (D) emission.

Recent Progress of Organic Semiconductor Materials in Spintronics.

Spintronics, a new discipline focusing on the spin-dependent transport process of electrons, has been developing rapidly. Spin valves are the most significant carriers of spintronics utilizing the spin freedom of electrons. It is expected to pierce "Moore's Law" and become the core component in processors of the next generation.

An Efficient Blue-Emission Crystalline Thin-Film OLED Sensitized by "Hot Exciton" Fluorescent Dopant.

Crystalline thin-film organic light-emitting diodes (C-OLEDs) can achieve a large light emission and a low Joule-heat loss under low driving voltage due to the high carrier mobility of the crystalline thin films. However, it is urgent for the C-OLEDs to improve their external quantum efficiency (EQE). Here, a novel strategy is proposed using a doped "hot exciton" material to sensitize a high PLQY blue emitter in C-OLEDs.

Origin of Photovoltaics in Organic Solar Cells at Negligible Energy Level Offsets─An Insight of the Charge Accumulation Effect.

Reducing the energy level offset is one of the key elements of low open-circuit voltage loss in organic solar cells. However, the origin of charge separation driving force at negligible energy level offsets still remains unexplained. Herein, from the perspective of built-in potential caused by charge accumulation, we discuss the nonequilibrium energy level displacement as current passing with distinct variable current densities.

Comprehending radicals, diradicals and their bondings in aggregates of imide-fused polycyclic aromatic hydrocarbons.

Quantum effects such as ferromagnetism were regarded as rare in organic materials. When reduced to radical states, imide-fused polycyclic aromatic hydrocarbons (IPAHs) have shown room-temperature ferromagnetism in our recent work, to be a potential candidate as ferromagnetic semiconductor. Here, we use variational Davydov ansatz parametrized by density functional theory to investigate the structural and optical properties of IPAHs and their radicals at both molecule and aggregate levels.

A solution-processed n-type conducting polymer with ultrahigh conductivity.

Conducting polymers (CPs) with high conductivity and solution processability have made great advances since the pioneering work on doped polyacetylene, thus creating the new field of 'organic synthetic metals,. Various high-performance CPs have been realized, which enable the applications of several organic electronic devices. Nevertheless, most CPs exhibit hole-dominant (p-type) transport behaviour, whereas the development of n-type analogues lags far behind and only a few exhibit metallic state, typically limited by low doping efficiency and ambient instability.

Stability of the Charged Nonfullerene Acceptors.

As an electric current passes through an organic semiconductor, a small number of organic molecules will inevitably act as a polaron state that is similar to an ionic charged state. The continuous device operation of organic semiconducting molecules is directly associated with the stability of the charged state. Herein, we choose the high-performance Y-series of nonfullerene acceptors to investigate the stability by a spectro-electrochemical technique.