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Singlet fission has emerged as a promising strategy to avoid the loss of extra energy through thermalization in solar cells. A family of dimers consisting of nitrogen‐doped pyrene‐fused acenes that undergo singlet fission with triplet quantum yields as high as 125 % are presented. They provide new perspectives for nitrogenated polycyclic aromatic hydrocarbons and for the design of new materials for singlet fission., Come Together: By introducing dibenzodiazahexacene moieties in a dimeric architecture, a new type of singlet fission material was obtained. Solvent‐dependent triplet quantum yields of up to 125 % were achieved.

In this contribution, we focused on integrating a phenylene-bridged dibenzodiazahexacene dimer (o-DAD), which is singlet fission (SF) active, onto single-walled carbon nanotubes (SWCNTs) as a low-energy sink for energetically low lying excited states that stem from SF. Spectroscopic and microscopic assays assisted in documenting that SWCNT/o-DAD feature high stability in THF as a result of electronic interactions between the individual constituents. For example, statistical Raman analysis underlined n-doping of SWCNTs in the presence of o-DAD. Fluorescence spectroscopy prompted an energy transfer between the individual constituents, a conclusion that was exclusively derived from the quenching of the o-DAD-centered fluorescence. Excitation spectroscopy with a focus on the SWCNT fluorescence confirmed independently this conclusion by showing o-DAD-centered features. Our work was rounded off by time-resolved transient absorption measurements with SWCNT/o-DAD, in which evidence was gathered for the sequential o-DAD-centered SF with an efficiency of 112% followed by a unidirectional energy transfer from o-DAD to SWCNT and a rapid deactivation. The energy transfer efficiency from SF products such as (S1S0)CT and 1(T1T1) exceeded the 100% threshold with values of 115%, which is conventionally found in energy transfer schemes.

Herein, we describe the synthesis of a hole transporting material based on a partially planarised quart-p-phenylene core incorporating tetraketal and diphenylamine substituents that show optimal energy levels and solubility for perovskite solar cell applications. The triple-cation perovskite devices incorporating such quart-p-phenylene derivatives show power-conversion efficiencies, short circuit currents, open circuit voltages, and fill factors that are comparable to those of spiro-OMeTAD.

We use pyrene-4,5,9,10-tetraketone molecules with substituents of varying bulkiness in the 2,7 positions to probe the generality and versatility of the previously reported on-surface coordination of two diketones with a single metal atom, leading to one-dimensional coordination polymers. Three different low index surfaces of group 11 metals (Cu, Ag and Au) are used to provide both the support and the metal atoms for metal-organic coordination. By real space visualisation with single molecule resolution employing scanning tunnelling microscopy we investigate the molecular self-assembly and show how this can be substantiated with the formation of metal-organic linear and cyclic oligomers, depending on the employed substrate.

The synthesis and characterisation of two pyrene-fused phenazinothiadiazole derivatives with different substituents is described. Light-emitting diodes incorporating such derivatives display red to near-infrared electroluminescence with emission peaks at wavelengths as long as 721 nm, illustrating that pyrene-fused bisphenazinothiadiazoles can serve as deep red and NIR emitters.

Polycyclic aromatic hydrocarbons that extend over 2 nm in one dimension are seen as monodisperse graphene nanoribbons, which have attracted significant attention for a broad range of applications in organic electronics and photonics. Herein we report the synthesis of a stable bisthiadiazole-capped pyrene-containing nanoribbon with 18 linearly fused rings (NR-18-TD). Thanks to the presence of alternating tert-butyl and tri-iso-butylsilyl groups, NR-18-TD is highly soluble in organic solvents and therefore its structure and fundamental optoelectronic, redox and electrical properties could be unambiguously established. This work illustrates that NR-18-TD is a promising soluble NR-based n-type semiconductor for applications in organic electronics. The authors are grateful to the Basque Science Foundation for Science (Ikerbasque), POLYMAT, the University of the Basque Country (Grupo de Investigación GIU17/054 and SGIker), Gobierno de España (Ministerio de Economía y Competitividad CTQ2016-77970-R and CTQ2015-71936-REDT), Gobierno Vasco (BERC program), CICECO-Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (FCT ref. UID/CTM/50011/2013), Diputación Foral de Guipúzcoa (OF215/2016(ES)) and the FP7 framework program of the European Union (Marie Curie Career Integration Grant No. 618247 (NIRVANA)). This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement no. 664878. This project has also received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement no. 722951)

The properties of graphene nanoribbons are highly dependent on structural variables such as width, length, edge structure, and heteroatom doping. Therefore, atomic precision over all these variables is necessary for establishing their fundamental properties and exploring their potential applications. An iterative approach is presented that assembles a small and carefully designed molecular building block into monodisperse N-doped graphene nanoribbons with different lengths. To showcase this approach, the synthesis and characterisation of a series of nanoribbons constituted of 10, 20 and 30 conjugated linearly-fused rings (2.9, 5.3, and 7.7 nm in length, respectively) is presented. We are grateful to the Basque Science Foundation for Science (Ikerbasque), POLYMAT, the University of the Basque Country (SGIker), the Deutsche Forschungsgemeinschaft (MA 5215/4-1), Gobierno de Espana (Ministerio de Economia y Competitividad CTQ2016-77970-R and CTQ2015-71936-REDT), Gobierno Vasco (BERC program and PC2015-1-01(0637)), Diputacion Foral de Guipuzcoa (OF215/2016(ES)), CICECO-Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (FCT ref. UID/CTM/50011/2013), ON2 (NORTE-07-0162-FEDER-000086), and the FP7 framework program of the European Union (ERA Chemistry, Marie Curie Career Integration Grant No. 618247 (NIRVANA)). This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 664878. This project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement no. 722951).

A pyrene-fused phenazinothiadiazole that shows electron mobilities (μe= 0.016 cm2V−1s−1) two orders of magnitude higher than those reported for pyrene-fused pyrazaacenes is described.

The synthesis, optoelectronic properties and near-infrared electroluminescent heterojunctions of a twisted and soluble 7,8,15,16,23,24-hexaazatrianthrylene derivative are reported.

Semiconductor organometallic halide (CH 3 NH 3 PbX 3 , X=Cl, Br, I) perovskites (HPVK) have been emerged as a potential gain media to construct a new generation of active photonic devices. Indeed, during the last three years a significant effort has been carried out to implement HPVK-based optical amplifiers or lasers with improved quality factors. In particular, minimization of the threshold of stimulated emission has been an important concern to decrease the power consumption, and hence to enhance the performances of the device. For this purpose strategies include a suitable integration of the semiconductor in a photonic structure, or the optimization of the material. Here we propose a novel approach to develop optical amplifiers by an appropriate passivation of HPVK layers incorporated in an optical waveguide. For this purpose, geometrical parameters were firstly properly optimized to demonstrate amplification of stimulated emission with a threshold as a low as 2 nJ. In addition, the passivation of traps of the semiconductor by introducing organic additives (twisted hexaazatrinaphthylene and bisthiadiazolefused tetraazapentacenequinone) resulted in a further reduction of the threshold (down to four fold). These results provide a novel scheme to enhance the applications of perovskite active devices.

The authors wish to thank the EPSRC for funding. PJS thanks the Royal Society for a Wolfson Research Merit Award. Star-shaped conjugated systems with varying oligofluorene arm length and substitution patterns of the central BODIPY core have been synthesised, leading to two families of compounds, T-B1-T-B4 and Y-B1-Y-B4, with T- and Y-shaped motifs, respectively. Thermal stability, cyclic voltammetry, absorption and photoluminescence spectroscopy of each member of these two families were studied in order to determine their suitability as emissive materials in photonic applications. Publisher PDF

Twisted two-dimensional aromatic frameworks have been prepared by overcrowding the nodes with bulky and rigid substituents. The highly distorted aromatic framework with alternating out-of-plane substituents results in diminished interlayer interactions that favor the exfoliation and dispersion of individual layers in organic media. We are grateful to the Basque Science Foundation for Science (Ikerbasque), POLYMAT, the University of the Basque Country (SGIker), the Deutsche Forschungsgemeinschaft (AU 373/3-1 and MA 5215/4-1), Gobierno de Espana/FEDER (Ministerio de Economia y Competitividad, CTQ2015-71936-REDT, CTQ2016-77970-R, and ENE2015-66975-C3), Gobierno Vasco (BERC program, PC2015-1-01(06-37), and IT1069-16), Diputacion Foral de Guipuzkoa (2015-CIEN-000054-01), CICECO-Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (FCT ref. UID/CTM/50011/ 2013), ON2 (NORTE-07-0162-FEDER-000086), the Fund of Scientific Research-Flanders (FWO), the Internal Funds KU Leuven, the Belgian Federal Science Policy Office (IAP-7/05), and the Nanoscale and Microscale Research Centre (NMRC, University of Nottingham, UK) for access to TEM. We have received funding for the research leading to these results from the European Union Seventh Framework Programme as a European Research Area Action (ERA-Chemistry) and a Marie Curie Action (Career Integration Grant No. 618247) and from the European Union Framework Programme for Research and Innovation Horizon 2020 as a Future and Emerging Technologies Action (FET Open) under Grant Agreement No. 664878 (2D-INK).

The synthesis and characterization of a tetraazapentacenequinone fused to two thiadiazoles is reported. This linear derivative constituting seven fused rings shows a very low LUMO level (-4.46 eV) and a low HOMO-LUMO gap (1.77 eV). Its high solubility, endowed by four triisopropylsilyl groups, allows the fabrication of air-stable field-effect transistors by liquid deposition methods that show electron mobilities up to 2.42 × 10(-3) cm(2) V(-1) s(-1) without any device optimization.

The authors thank EPSRC for fi nancial support from the UP-VLC project grant (EP/K00042X/1). P.J.S. and I.D.W.S. also acknowledge a Royal Society Wolfson Research Merit Award. Star-shaped organic semiconductors with boron dipyrromethene (BODIPY) cores are color-conversion materials for blue LED-based visible light communications. The difference between 0 and 1 bits is resolved in colour-converted data links at 100 Mb s−1. The BODIPY modulation bandwidth is eight times higher than that measured using conventional phosphor color converters. Publisher PDF

The search for new organic electron‐donor and electron‐acceptor materials has attracted enormous interest since the early 1970s. Since then, a vast number of different families of compounds have been developed and undoubtedly, among the electron donors, sulfur‐containing molecules represent an important series of compounds (e.g. derivatives of TTF and thiophene). In some cases, the larger chalcogen atoms, selenium and tellurium, have also been incorporated into the structures by substituting the sulfur atoms partially or completely to obtain more extensive intermolecular interactions and improved charge transport properties. In this chapter, we focus on the presentation of the main series of chalcogen‐rich electron donors and, when suitable, on a critical comparison of the properties of these materials by substitution with different chalcogen atoms. In the second edition of this chapter, we have incorporated the most relevant literature since the publication of the first edition, as well as a wider perspective of the application of these chalcogen‐rich compounds as electron donors

The efficiency of perovskite optoelectronic devices is increased by a novel method; its suitability for perovskite solar cells, light-emitting diodes, and optical amplifiers is demonstrated. The method is based on the introduction of organic additives during the anti-solvent step in the perovskite thin-film deposition process. Additives passivate grain boundaries reducing non-radiative recombination. The method can be easily extended to other additives.

A new terthiophene–diketopyrrolopyrrole (DPP) copolymer has been synthesised in which the central thiophene ring within the terthiophene repeat unit is attached to a fused tetrathiafulvalene (TTF). The electrochemical and absorption data of the polymer, p(DPP-TTF), are presented, and the multi-redox states are investigated by UV-vis spectroelectrochemistry. Bottom gate/bottom contact field effect transistors were fabricated from films of p(DPP-TTF) annealed at 200 °C. The material, which under these conditions forms a fibrous structure, exhibited hole mobilities of 4 ± 2 × 10−2 cm2 V−1 s−1 with an on/off ratio of 1 × 104. The transistors showed little sign of degradation over 15 days of exposure under ambient conditions, demonstrating excellent air-stability. This characteristic is attributed to the incorporation of the TTF unit into the polymer.

Star-shaped nanographenes are large monodisperse polycyclic aromatic hydrocarbons that extend in size beyond the nanometer and have shown a lot of promise in a wide range of applications including electronics, energy conversion and sensing. Herein we report a new family of giant star-shaped N-doped nanographenes with diameters up to 6.5 nm. Furthermore, the high solubility of this SNG family in neutral organic solvents at room temperature allowed a complete structural, optoelectronic and electrochemical characterisation, which together with charge transport studies illustrate their n-type semiconducting character.

The chemical processing of low-dimensional carbon nanostructures is crucial for their integration in future devices. Here we apply a new methodology in atomically precise engineering by combining multistep solution synthesis of N-doped molecular graphene nanoribbons (GNRs) with mass-selected ultra-high vacuum electrospray controlled ion beam deposition on surfaces and real-space visualisation by scanning tunnelling microscopy. We demonstrate how this method yields solely a controllable amount of single, otherwise unsublimable, GNRs of 2.9 nm length on a planar Ag(111) surface. This methodology allows for further processing by employing on-surface synthesis protocols and exploiting the reactivity of the substrate. Following multiple chemical transformations, the GNRs provide reactive building blocks to form extended, metal-organic coordination polymers. This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreements No. 946223 and No. 899895. Financial support was provided by the German Research Foundation (DFG) through the TUM International Graduate School of Science and Engineering (IGSSE), Excellence Cluster e-conversion, and the priority programme 1928 COORNETs, the China Scholarship Council (CSC) and the European Research Council (ERC) (no. 722951). This project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (Grant Agreement No. 722951). This work was carried out with support from the Basque Foundation for Science (Ikerbasque), POLYMAT, the University of the Basque Country, Gobierno Vasco (BERC programme). Technical and human support provided by SGIker of UPV/EHU and European funding (ERDF and ESF) is acknowledged. Open Access funding enabled and organized by Projekt DEAL.