Showing papers on "Pentacene published in 1983"
50 citations
TL;DR: In this paper, the energy spectrum of electrons backscattered from polycrystalline pentacene films has been measured for incident elecron energies between 5 and 40 eV, with an energy resolution ≈150 meV and an angular resoluton ≈5°.
31 citations
TL;DR: In this paper, the authors measured the fluorescence spectra and lifetimes of anthracene, tetracene and pentacene molecules in a host p-terphenyl single crystalline lattice over the temperature range 10-300 K.
Abstract: The fluorescence spectra and lifetimes of anthracene, tetracene and pentacene molecules in a host p-terphenyl single crystalline lattice have been measured over the temperature range 10–300 K. At low temperatures the molecules occupy different sites in the host lattice: five for anthracene (O1, O2, O3, O4, O5), six for tetracene (O1, O2, A1, A2, A3, A4) and four for pentacene (O1, O2, O3, O4). The high-temperature fluorescence spectra are dominated by particular sites (O4/O5 for anthracene, A2/A4 for tetracene and O1/O2 for pentacene) and the temperature dependence of the fluorescence lifetime of these sites is recorded. Neither O4/O5 for anthracene nor A2/A4 for tetracene exhibit a marked temperature dependence whereas the lifetime of O1/O2 for pentacene decreases with increasing temperature with an activation energy of 60–90 cm–1. This temperature dependence is associated with an increased probability for intersystem crossing from O1/O2 to a triplet level (T2) of the pentacene molecule which is located at 16 960 ± 15 cm–1. For anthracene and tetracene T2 is inaccessible from all sites over the entire temperature range and for anthracene the short lifetime reflects the facile transfer of excitation from S1 to T1.
21 citations