Two-Dimensional Diffusion of Excitons in a Perylene Diimide Monolayer Quenched by a Fullerene Heterojunction

Abstract

The structural and functional properties of organic heterojunctions play a vitally important role in the operation of organic devices, but their properties are difficult to measure directly due to the buried interfaces that are typically formed. We have grown model heterojunctions consisting of two monolayer-thick organic semiconductors and used these bilayers to explore the two-dimensional dynamics of excitons. The heterostructures are formed by sequential deposition of monolayers of perylene-3,4,9,10-tetracarboxylic-3,4,9,10-diimide (PTCDI) and fullerene (C60) on hexagonal boron nitride (hBN). The morphology of these bilayers was characterized using atomic force microscopy and showed clear differences in the C60 growth kinetics on hBN and PTCDI. The variation in the fluorescence of PTCDI-C60 heterostructures with increasing fullerene coverage showed a reduction in intensity consistent with exciton diffusion and quenching. We use a simple model for the intensity dependence to determine the two-dimensional exciton diffusion length in a PTCDI monolayer, finding a value of 17 ± 3 nm for this parameter.

Effect of masses of active layers of C60-4-methylphenylhydrazone N-isoamylisatin fullerene heterostructures on their rectifying characteristics

“…Solar energy is not the only area of application of organic materials. Organic field effect transistors (OFET) over the past 5 years have been widely used due to the control of the initial chemical composition of the substance [6,7]. In particular, OFETs using carbon materials (fullerenes) as a basis are effectively used due to the high electron mobility (11 cm 2 V -1 s -1 ) [8].…”

Recent Progress and Challenges in Perylene Small Molecules, Assemblies and Composites for Photocatalytic Hydrogen Evolution

“…In the last decade, PDI based n‐type organic semiconductors have attracted great attention in photocatalytic hydrogen evolution (half reaction) from water [15] . Perylene derivatives have extended π‐conjugation, rigid planar backbones, high charge‐carrier mobilities, extraordinary photochemical and thermal stabilities, appreciable and tunable visible light absorption, strong self‐assembly properties, low‐lying frontier molecular orbitals and near‐unity fluorescence quantum yields [19–23] . Perylene framework offers several positions for the attachment of substituents around the core, namely, the “imide”, “bay”, “ortho”, and the “peri” positions and hence provide wide possibilities for structural tunability [24] .…”

Triplet Excitation and Electroluminescence from a Supramolecular Monolayer Embedded in a Boron Nitride Tunnel Barrier

“…The FLG provides semitransparent top- and bottom-electrodes, and the hBN layers allow carrier injection via tunnelling under an applied bias, while suppressing quenching from the FLG contacts . PTCDI is a planar molecule and is adsorbed parallel to the hBN substrate in 2D islands stabilized by hydrogen bonding . The islands have monolayer height and typical lateral dimensions of 5–10 μm, and for the deposition parameters we use (see Supporting Information) a surface coverage of 50%.…”

“…13 PTCDI is a planar molecule and is adsorbed parallel to the hBN substrate in 2D islands stabilized by hydrogen bonding. 14 The islands have monolayer height and typical lateral dimensions of 5−10 μm, and for the deposition parameters we use (see Supporting Information) a surface coverage of 50%. The molecular ordering within the islands is resolved using atomic force microscopy (AFM), which reveals lattice vectors close to the expected value 14 (see Figure 1b).…”

“…14 The islands have monolayer height and typical lateral dimensions of 5−10 μm, and for the deposition parameters we use (see Supporting Information) a surface coverage of 50%. The molecular ordering within the islands is resolved using atomic force microscopy (AFM), which reveals lattice vectors close to the expected value 14 (see Figure 1b). At a large scale, individual monolayer PTCDI islands may be identified using optical microscopy during the transfer process (Figure 1c).…”