Electronic Spectra of C₆₀ Films Using Screened Range Separated Hybrid Functionals

Abstract

We study computationally the electronic spectra of C 60 thin films using the recently developed density functional theory (DFT) framework combining a screened range separated hybrid (SRSH) functional with a polarizable continuum model (PCM). The SRSH-PCM approach achieves excellent correspondence between the frontier orbital's energy levels and the ionization potential and electron affinity of the molecular system at the condensed phase and consequently leads to high quality electronic excitation energies when used in time-dependent DFT calculations. Our calculated excited states reproduce the experimentally main reported spectral peaks at the 3.6−4.6 eV energy range and when addressing excitonic effects also reproduce the red-shifted spectral feature. Notably, we analyze the low-lying peak at 2.7 eV and associate it to an excitonic state.

Spectroscopic Identification of the Charge Transfer State in Thiophene/Fullerene Heterojunctions: Electroabsorption Spectroscopy from GW/BSE Calculations

“…Predictions of the IP and EA of gas phase C 60 from several GW − and TDDFT calculations are available. The experimental IP and EA values in the gas phase are 7.6 and 2.7 eV, respectively.…”

A Computational Study of the Electronic Energy and Charge Transfer Rates and Pathways in the Tetraphenyldibenzoperiflanthene/Fullerene Interfacial Dyad

“…Thus, dielectric screening is addressed consistently by the self-consistent reaction field responding to the dielectric constant, ϵ 0 , within the PCM and by damping the LR exchange in the SRSH functional. The combined SRSH-PCM approach has been shown in previous work to significantly improve RSH-PCM calculations of fundamental gaps and of excited states ,− ,− including CT states in organic semiconductors . SRSH-PCM was also recently successfully applied to interpret the spectral signature of interfacial CT in DBP:C 70 blends …”

“…The electronic structure protocol we use is based on DFT with a screened range separated hybrid (SRSH) functional that addresses dielectric screening by the solid state environment in a polarization-consistent manner. , Combining SRSH with the polarizable continuum model (PCM) is important for obtaining the correct order of the energy levels that correspond to the neutral and CT excited electronic states. SRSH-PCM was previously used successfully to analyze spectral trends in organic systems ,− including fullerenes . We also point out the high density of states in fullerene due to its high symmetry, which calls for an electronic structure level of theory that can capture the correct order of energy levels in such a case.…”

“…SRSH-PCM was previously used successfully to analyze spectral trends in organic systems 7,17−19 including fullerenes. 19 We also point out the high density of states in fullerene due to its high symmetry, which calls for an electronic structure level of theory that can capture the correct order of energy levels in such a case.…”

Simulation Studies on External Electric Field-Dependent Anisotropy of Two-Dimensional Fullerene Nanomaterials qTP C60 and qHP C60: Implications for Photoelectric Nanodevices

“…Owing to these advantageous features, C 60 is considered an irreplaceable material with a great application potential in numerous high-tech fields. , To date, tens of thousands of fullerene derivatives solely based on C 60 have been synthesized, imparting extremely rich properties to the fullerene family and facilitating the development of numerous applications. Fullerenes are super nanomaterials with broad prospects for application as energy, chemical, medical, and basic materials. , Furthermore, the unusual properties of fullerenes suggest their profound impact on chemistry, physics, materials, medicine, microelectronics, and other fields. − …”