Resonant Raman spectra of diindenoperylene thin films

Abstract

Resonant and preresonant Raman spectra obtained on diindenoperylene (DIP) thin films are interpreted with calculations of the deformation of a relaxed excited molecule with density functional theory (DFT). The comparison of excited state geometries based on time-dependent DFT or on a constrained DFT scheme with observed absorption spectra of dissolved DIP reveals that the deformation pattern deduced from constrained DFT is more reliable. Most observed Raman peaks can be assigned to calculated A(g)-symmetric breathing modes of DIP or their combinations. As the position of one of the laser lines used falls into a highly structured absorption band, we have carefully analyzed the Raman excitation profile arising from the frequency dependence of the dielectric tensor. This procedure gives Raman cross sections in good agreement with the observed relative intensities, both in the fully resonant and in the preresonant case.

Plasmon resonance modulated photoluminescence and Raman spectroscopy of diindenoperylene organic semiconductor thin film

“…1a) appeared at 520, 634, 1284, 1395, 1459 and 1608 cm À 1 . Except for the intense Raman peak at 520 cm À 1 and a broad 2 phonon band around 960 cm À 1 originating from the Si substrate [16], all other Raman cross-sections can be assigned to the in-plane C-C stretching vibrations and C-H bending modes of a DIP molecule [4,17]. The PL from DIP increases towards larger Stokes shift, saturating the detector above 2750 cm À 1 .…”

Structure and Morphology of Organic Semiconductor–Nanoparticle Hybrids Prepared by Soft Deposition

“…The sharp peaks (shown by arrows in Figure 9) superimposed on the broad PL peak correspond to the Raman lines showing different vibrational modes of DIP. 71,72 All data were normalized with respect to the Raman peak for Si at 520 cm −1 for comparison.…”

Spectroscopic Assessment of Charge Mobility in Organic Semiconductors

“…(4), 2 1 i q = since the HF vibrations are not thermally populated, and the variance of qi is determined by zero-point oscillations, making the HF Raman intensity nearly temperatureindependent. 35 In contrast, the LF vibrations are populated at room temperature, and we expect decrease of LF Raman intensity with cooling due to the decrease of 2 i q . 35 To summarize, Eqs.…”

“…In those studies, analysis of the (pre-) resonant Raman intensities in the HF and LF ranges was exploited to extract information about local 29,30 and non-local 31,32 electron-phonon coupling, respectively. Although earlier attempts to associate the Raman intensities to the contributions of intramolecular modes to local electron-phonon interaction were made for other OSs, [33][34][35][36] further extension of this approach to address the dynamic disorder and estimate µ in OSs is lacking.…”