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Organic polymer nanomechanics has been explored through precise nanometre-scale stiffness measurements in a high-mobility semiconducting polymer. Higher eigen-mode atomic force microscopy is used to measure nanomechnical variations in the film texture, as well as the nanoscale order in the material.

Abstract The electrochemiluminescence (ECL) behavior of a multiresonance thermally activated delayed fluorescence molecule has been investigated for the first time by means of ECL‐voltage curves, newly designed ECL‐time observatory, and ECL spectroscopy. The compound, Mes3DiKTa, shows complex ECL behavior, including a delayed onset time of 5 ms for ECL generation in both the annihilation pathway and the coreactant route, which we attribute to organic long‐persistent ECL (OLECL). Triplet‐triplet annihilation, thermally activated delayed fluorescence and uncompensated solution resistance cannot be ruled out as contributing mechanisms to the ECL. A very long ECL emission decay was attributed to OLECL as well. The absolute ECL efficiencies of Mes3DiKTa were enhanced and reached 0.0013% in annihilation route and 1.1% for the coreactant system, which are superior to those of most other organic ECL materials. It is plausible that ECL materials with comparable behavior as Mes3DiKTa are desirable in applications such as ECL sensing, imaging, and light‐emitting devices.

A low singlet-triplet energy gap, necessary for delayed fluorescence organic semiconductors, results in a small radiative rate that limits performance in OLEDs. Here, the authors show that it is possible to reconcile these conflicting requirements in materials that can access both high oscillator strength intramolecular excitations and intermolecular charge transfer states.

Spiro compounds are widely used as host matrices in organic light‐emitting diodes (OLEDs). Here, inspired by the recent developments in thermally activated delayed fluorescence (TADF) materials, the potential as a light emitter of two spiro‐configured organic semi‐conductors is investigated, constructed by the association of quinolinophenothiazine (QPTZ) or indoloacridine (IA) as the electron‐rich fragment and diphenylphosphine oxide fluorene as the electron‐poor fragment. By comparison with structural analogues lacking phosphine oxides, the crucial role played by these electron‐accepting substituents not only on the photo‐physical properties but also on the device performances is evidenced. Despite a very low quantum yield in solution, these two compounds unexpectedly display good emission properties when incorporated as a pure layer in OLEDs, thus highlighting the role of intermolecular effects.

Designing conjugated polymers with high charge carrier mobility and fluorescence quantum efficiency, though attractive for optoelectronics, remains challenging. Here, the authors report a strategy for designing donor-acceptor copolymers whose optoelectronic properties exceed the state-of-the-art.

Thermally activated delayed fluorescence is a mechanism for enhancing the efficiency of organic light emitting diodes by harvesting triplet excitons, but there is still a need to design more efficient materials. Here, the authors rationally design and characterize a series of π-extended boron- and nitrogen-doped nanographenes as promising candidates.

Photochromic molecules offer the unique opportunity to demonstrate multifunctional devices with light-tunable electrical characteristics. Gobbi et al. build light-switchable electronic heterojunctions based on atomically precise, photo-reversible molecular superlattices on graphene and MoS2.

Two-dimensional material heterostructures enable unique electronic features by introducing periodic potentials. Here, Gobbiet al. use a monolayer supramolecular lattice with a tunable one-dimensional periodic potential to modify the electronic structure of graphene.

In this paper we describe the mechanism of light emission through thermally activated delayed fluorescence (TADF)—a process able to ideally achieve 100% quantum efficiencies upon fully harvesting the energy of triplet excitons, and thus minimizing the energy loss of common (i.e., fluorescence and phosphorescence) luminescence processes. If successful, this technology could be exploited for the manufacture of more efficient organic light-emitting diodes (OLEDs) made of only light elements for multiple daily applications, thus contributing to the rise of a sustainable electronic industry and energy savings worldwide. Computational and theoretical studies have fostered the design of these all-organic molecular emitters by disclosing helpful structure−property relationships and/or analyzing the physical origin of this mechanism. However, as the field advances further, some limitations have also appeared, particularly affecting TD-DFT calculations, which have prompted the use of a variety of methods at the molecular scale in recent years. Herein we try to provide a guide for beginners, after summarizing the current state-of-the-art of the most employed theoretical methods focusing on the singlet−triplet energy difference, with the additional aim of motivating complementary studies revealing the stronger and weaker aspects of computational modelling for this cutting-edge technology.

The original version of this article incorrectly listed an affiliation of Sara Bonacchi as ‘Present address: Institut National de la Recherche Scientifique (INRS), EMT Center, Boulevard Lionel-Boulet, Varennes, QC, J3X 1S2, 1650, Canada’, instead of the correct ‘Present address: Department of Chemical Sciences - University of Padua - Via Francesco Marzolo 1 - 35131 Padova - Italy’. And an affiliation of Emanuele Orgiu was incorrectly listed as ‘Present address: Department of Chemical Sciences, University of Padua, Via Francesco Marzolo 1, Padova, 35131, Italy’, instead of the correct ‘Present address: Institut National de la Recherche Scientifique (INRS), EMT Center, Boulevard Lionel-Boulet, Varennes, QC, J3X 1S2, 1650, Canada’. This has been corrected in both the PDF and HTML versions of the article.

We report a joint experimental and theoretical study on the electronic structure and the solid-state organisation of bis(naphthoquinone)-tetrathiafulvalene (BNQ-TTF) as a promising ambipolar semiconductor. Accordingly, organic field-effect transistors (OFETs) fabricated with this material show both hole and electron transport for the first time in TTF derivatives. [ABSTRACT FROM AUTHOR]