Nanosecond pump and probe observation of bimolecular exciton effects in rubrene single crystals

Abstract

Transient grating pump and probe experiments are used to investigate excitonic processes on the nanosecond time scale in rubrene single crystals. We find that bimolecular interactions cause a photoinduced excited state density on the order of 0.5 × 1020 cm−3—corresponding to an average distance of ∼3 nm between individual states—to decrease by a factor of 2 after 2 ns, following a typical power-law decay. We assign the observed power-law decays to high-density interactions between excited states. Because of the high efficiency singlet exciton fission observed in rubrene, these bimolecular interactions are likely those between triplet excitons or between coherent quantum superpositions of a singlet and a pair of triplet-excitons.

Two Birds with One Stone: Tailoring Singlet Fission for Both Triplet Yield and Exciton Diffusion Length

“…Singlet fission in single‐crystalline TIPS‐pentacene is found to be fastest with a decay constant τ SF of ≈5 ps, whereas the singlet fission time in tetracene is the slowest with τ SF ≈120 ps, agreeing well with other studies . Singlet fission in the rubrene crystal is measured to be ≈70 ps consistent with previously reported values ranging from 20 to 80 ps . Despite the differences in fission rate and DE SF , singlet fission efficiency has been reported to be close to 100% in all three crystals .…”

3D Electron Diffraction Structure Determination of Terrylene, a Promising Candidate for Intermolecular Singlet Fission

“… [97] Terrylene is positioned between rubrene and tetracene. SF has been experimentally observed in crystals of both rubrene[ 98 , 99 , 100 , 101 , 102 , 103 ] and tetracene. [ 104 , 105 , 106 , 107 , 108 , 109 , 110 ] SF with a high triplet yield has also been observed in thin films of terrylene derivatives with different packing motifs.…”

High-Throughput Pressure-Dependent Density Functional Theory Investigation of Herringbone Polycyclic Aromatic Hydrocarbons: Part 1. Pressure-Dependent Structure Trends

“…There are three aryl-substituted oligoacenes in the HB motif that show varying pressure-dependent behavior: 9,10-diphenylanthracene (DPANTR01), rubrene (QQQCIG04), and 5,7,12,14-tetraphenylpentacene (VEBJES) (structures shown in Figure a–c). These structures are of interest to device manufacturers because they have shown high-charge carrier mobilities as well as possible singlet fission activity. ,− The structure of DPANTR01 contains an anthracene backbone with two phenyl groups substituent at the 9 and 10 positions tilted by ∼66° with the anthracene backbone. The unit cell of DPANTR01 is from the most stable α-polymorph, which is monoclinic with the C 2/ c space group. , Rubrene has a tetracene backbone and four phenyls substituent at the 5, 6, 11, and 12 positions.…”