When molecular dimers, crystalline films or molecular aggregates absorb a photon to produce a singlet exciton, spin-allowed singlet fission may produce two triplet excitons that can be used to generate two electron-hole pairs, leading to a predicted ∼50% enhancement in maximum solar cell performance. The singlet fission mechanism is still not well understood. Here we report on the use of time-r...

The history and development of pyrazineand pyridine-type heteroacenes and their use in solid-state organic electronics are discussed and reviewed. The larger N-heteroacenes are potential electronor hole-transporting materials and should therefore complement acenes in organic electronics. As they feature electronegative nitrogen ring atoms in their molecular skeleton, issues with oxidation shoul...

The ultrafast spectroscopy of single domains of polycrystalline films of TIPS-pentacene, a small-molecule organic semiconductor of interest in electronic and photovoltaic applications, is investigated using transient absorption microscopy. Individual domains are distinguished by their different polarization-dependent linear and nonlinear optical responses. As compared to bulk measurements, we s...

Charge transfer states in blends of organic semiconductors have significant importance for the functioning of organic optoelectronic devices, but are also interesting from the perspective of fundamental research as many of their properties as well as their influence on the photophysics of the material are not yet completely understood. We report on a time-resolved photoluminescence study of the...

We present an original hybrid QM/MM scheme merging the many-body Green's function GW formalism with classical discrete polarizable models and its application to the paradigmatic case of a pentacene crystal. Our calculated transport gap is found to be in excellent agreement with reference periodic bulk GW calculations, together with properly parametrized classical microelectrostatic calculations...

The application of organic electronic materials for the detection of ionizing radiations is very appealing thanks to their mechanical flexibility, low-cost and simple processing in comparison to their inorganic counterpart. In this work we investigate the direct X-ray photoconversion process in organic thin film photoconductors. The devices are realized by drop casting solution-processed bis-(t...

We report the doping induced changes of the electronic structure of tetracene and pentacene probed by electron energy-loss spectroscopy in transmission. A comparison between the dynamic response of undoped and potassium-intercalated tetracene and pentacene emphasizes the appearance of a new excitation feature in the former gap upon potassium addition. Interestingly, the momentum dependency of t...

Singlet fission, the conversion of a singlet excitation into two triplet excitations, is a viable route to improved solar-cell efficiency. Despite active efforts to understand the singlet fission mechanism, which would aid in the rational design of new materials, a comprehensive understanding of mechanistic principles is still lacking. Here, we present the first study of singlet fission in crys...

In this paper, the fabrication and characterisation of pentacene-based photoconductors using indium tin oxide electrodes obtained by ion beam sputtering are discussed. The photoelectric properties of pentacene under red (632 nm) and ultraviolet (365 nm) illuminations were investigated. We have shown that the photocurrent was dependent on the wavelength, bias voltage and illumination side of the...