Search

Understanding molecular arrangements in mechanistic studies of complex materials is critical but challenging. Here, the authors develop a hierarchical incremental learning protocol to uncover microscopic patterns, improving mechanistic insights obtained

The use of conventional X-ray scattering techniques is challenging to detect donor-acceptor contrast within amorphous intermixing regions. Here, the authors apply neutron scattering and targeted deuteration to enhance the contrast by one order of magnitude and reveal short-range aggregations of d-Y6.

Traps in organic semiconducting crystals are healed when a perfluoropolyether oil is deposited on the surface of these materials, thus making possible the detection of intrinsic features of charge-carrier transport in rubrene and tetracene.

Insight into the singlet–triplet energy gap and molecular structure relationship in polycyclic heteroaromatic molecules enables organic light-emitting diodes based on multiresonance thermally activated delayed fluorescence, with improved efficiency and roll-off.

Chemical doping allows for boosting the conductivity in conjugated polymers but the relationship between doping and the polymers’ complex, multiscale morphology remains elusive. Here the authors report that supramolecular chirality, which up to now had not been considered a parameter relevant to doping, significantly boosts the underpinning redox reaction in conjugated polymer thin films.

Organic radical molecules violating the Aufbau principle are shown to reach high luminescence quantum yield and photostability, with potential applications for deep-red and near-infrared light-emitting sources.

Triplet excited states related to partial molecular structures are shown to mediate spin-flip between lowest singlet and triplet excited states in multiple donor–acceptor charge-transfer-type organic molecules.

By varying the distance between two electrodes bridged by a single molecule, the interaction between charges passing through the molecular junction and their mirror images in the metal contacts can be observed.

The solvent choice for processing organic solar cells impacts layer morphology and ultimately device performance. By controlling the molecular interactions, Zhang et al. realize a solvent-independent morphology that leads to high device efficiency.

Previous descriptions of the charge-transfer absorptions in organic solar cells only involve the charge transfer state and the ground state. Here Chen et al. underline that a third state, i.e., the local absorbing state on the donor and/or acceptor, needs to be considered.

Large acene molecules are common components of organic electronics. Appletonet al.show that embedding pyrazine units in acenes results in unexpected red-shifted optical transitions upon electronegative substitution, which may aid the design of acene-type materials for organic electronics applications.

The material used for the dielectric layer in organic field-effect transistors strongly affects the efficiencies of the resulting devices. The reasons behind this connection, and opportunities to tune the device performance by changing the dielectric material, are now revealed.

Fullerene acceptors are relevant for upscaling industrial production of organic solar cells. Here, authors reveal that for donor-acceptor blends with low energetic offset, charge transfer state dissociation rather than charge transfer state formation presents a bottleneck for free charge generation.

The performance of Y6-containing donor-acceptor active layers in organic solar cells is highly related to the charge-transfer nature in Y6 aggregates. Here, authors study charge-transfer characteristics of excitations of isolated and aggregated Y6 molecules through electroabsorption spectroscopy.

High-performance organic solar cells call for novel designs of acceptor molecules. Here, He et al. design and synthesize a non-fullerene acceptor with an asymmetric structure for diverse donor:acceptor interfacial conformations and report a certificated power conversion efficiency of 18.2%.

Organic solar cells based on non-fullerene acceptors have enabled high efficiencies yet their charge dynamics and its impact on the photovoltaic parameters are not fully understood. Now, Chen et al. provide a general description of non-radiative voltage losses in both fullerene and non-fullerene solar cells.

Low-k dielectric materials are essential to allow continued electronics miniaturization, but their low thermal conductivity limits performance. Here, two-dimensional covalent organic frameworks are shown to combine high thermal conductivity with a low dielectric constant.

The electronic properties of organic molecules are sensitive to structural dynamics, but device control through this phenomenon has not been attained. Bakulinet al. show that the photoconductivity can be modulated by selective excitation of molecular vibrations in an organic optoelectronic device.

The understanding of strain effect on electronic properties of organic semiconductors is crucial for the designs of flexible electronics. Here, Wu et al.characterize the tensile and compressive strain effects on the work function of rubrene single crystals as a benchmark system.

Hybrid perovskite is a promising class of material for optoelectronic applications due to the slow hot-carrier cooling, yet the process is not well-understood in material with Rashba band splitting. Here, the authors reveal spin-flipping and spin-dependent scattering of hot electrons are responsible for accelerating the cooling at longer delays.

Key optoelectronic properties for donor and acceptor organic semiconductors are identified to obtain organic solar cells with reduced open-circuit voltage losses and high power conversion efficiencies.

An organic molecule, 5Cz-TRZ, with multiple donor units supports fast reverse intersystem crossing, allowing fabrication of high-performance organic light-emitting diodes.

Y6, as a non-fullerene acceptor for organic solar cells, has attracted intensive attention because of the low voltage loss and high charge generation efficiency. Here, Zhang et al. find that the delocalization of exciton and electron wavefunction due to strong π-π packing of Y6 is the key for the high performance.

Near-infrared organic light-emitting diodes that operate in the 700 nm region with an external quantum efficiency of almost 10% are reported.

Small molecular additives incorporated into films of conjugate polymers are shown to fill the voids present in the polymer network. As a result, the stability of organic transistors based on these materials is significantly improved.

Semiconducting polymers are usually prepared by transition metal mediated coupling reactions that cause problems for sustainability and biological applications. Here the authors synthesise fused electron deficient polymers that are air stable and have high electron affinities, via metal free aldol polymerisation reactions.

Molecular orientation profoundly affects the performance of donor-acceptor heterojunctions, whilst it has remained challenging to investigate the detail. Using a controllable interface, Ran et al. show that the edge-on geometries improve charge generation at the cost of non-radiative recombination loss.

This work reports a quantitative investigation of the interaction parameter and miscibility of donor and acceptor organic molecules and their relationship with the fill factor and photovoltaic performance of bulk-heterojunction organic solar cells.

The charge-transfer electronic states that form at the interfaces between electron-donor and electron-acceptor components have a key role in the electronic processes in organic solar cells. This Review describes the current understanding of how these charge-transfer states affect device performance.

Non-fullerene acceptors open the way to sensitive organic photodetectors for detecting circularly polarized near-infrared light.

Lessons learned from coherent phenomena in biological photosynthetic systems may be useful to improve energy- and charge-transport in disordered materials. This Review describes coherence and its potential beneficial effects in photovoltaics.