Resonance Raman Spectra of a Perylene Bis(dicarboximide) Chromophore in Ground and Lowest Triplet States

Abstract

Resonance Raman spectroscopy is employed to probe the ground (S0) and lowest triplet (T1) excited states of a perylene bis(dicarboximide) (PDI) dimer. Four bands at ~1324, 1507, ~1535, and 1597 cm(-1) are signatures of the T1 excited state; a fifth band at ~1160 cm(-1) is tentatively assigned. Density functional calculations of an asymmetrically substituted PDI monomer match the experimental bands of the PDI dimer in both S0 and T1 states. The match supports a T1 excited state that is localized on a single PDI moiety of the dimer. The normal modes of the asymmetrically substituted PDI are correlated with ones calculated for the unsubstituted PDI in the D2h point group. Patterns in the Raman intensities are consistent with an A-term mechanism of enhancement. The positions of six bands are predicted for the resonance Raman spectrum of unsubstituted PDI in its T1 excited state. The spectra and normal-mode analysis reported here are expected to facilitate future studies of singlet fission in PDI crystals or other assemblies.

Supramolecular organic nanofibers with highly efficient and stable visible light photooxidation performance

“…[14] Therefore, we can utilize the 1602 cm -1 /1318 cm -1 Raman intensity ratio as an effective marker to monitor the degree of π-π stacking in PDI. [26] The relative intensity of 1602 cm -1 to 1318 cm -1 in nano PDI sample was about 0.67, which was higher than that of bulk PDI (0.44), indicating higher order π-π stacking in nano PDI. Fig.…”

Photo-Induced Doping in a Graphene Field-Effect Transistor with Inkjet-Printed Organic Semiconducting Molecules

“…The results of the Raman measurements for PDI-C6 modified graphene are presented in Figure 2a. PDI-specific peaks could be determined precisely in the spectra of both PDI-C6 samples (PDI-C6 powder and PDI-C6 layer on graphene), their locations being determined as 1305 and 1383 cm −1 (in-plane ring "breathing"), 1354 cm −1 (out-of-plane C-C stretching), 1462 cm −1 (ring deformation), and 1581 cm −1 (in-plane C-C stretching), respectively [24,25]. As far as PDI-C6 molecule consists of seven benzene rings, it has the vibration mode both for in-plane and out of plane C-C, which are clearly observed via Raman for both powder and thin film on the graphene surface that can interfere the D and G-bands of graphene.…”

“…It should be noted that in the presence of graphene, the luminescence background observed for PDI powder is quenched, which allows one to measure a clear Raman signal on emitting molecules [29]. The emission background is eliminated by charge transfers from PDI to graphene [25]. cm −1 (out-of-plane C-C stretching), 1462 cm −1 (ring deformation), and 1581 cm −1 (in-plane C-C stretching), respectively [24,25].…”

“…The emission background is eliminated by charge transfers from PDI to graphene [25]. cm −1 (out-of-plane C-C stretching), 1462 cm −1 (ring deformation), and 1581 cm −1 (in-plane C-C stretching), respectively [24,25]. As far as PDI-C6 molecule consists of seven benzene rings, it has the vibration mode both for in-plane and out of plane C-C, which are clearly observed via Raman for both powder and thin film on the graphene surface that can interfere the D and G-bands of graphene.…”

Resonance Raman study of the J-type aggregation process of a water soluble perylene bisimide

“…Moreover, RR spectroscopy has been adopted in the field of biosensors to accurately measure the strength of host-guest complexations. 36,37 Even though RR has been utilized for the characterization of a plethora of supramolecular systems, PBIs have only been analyzed by Raman spectroscopy as individual molecules 38,39 and not in their J aggregated state. This spectroscopic method is very powerful especially due to the selectivity to a particular chromophore: by tuning the excitation wavelength to the absorption band of a particular chromophore in a chemical system, chromophore-related vibrations only are substantially enhanced.…”