Molecular tuning of non-fullerene electron acceptors in organic photovoltaics: a theoretical study

Abstract

Modifying backbone, side chains and end groups of non-fullerene acceptors (NFAs) in organic photovoltaics (OPVs) can tune their properties, and then impact on performance. Hence, understanding how the different functional...

Modulating the organic photovoltaic properties of non-fullerene acceptors by molecular modification based on Y6: a theoretical study

“…This type of method has been widely used in many previous works and achieved good results. 27,35,37 Hence, the electronic structures and related properties in this work were calculated using the optimally tuned screened range separated hybrid (OTSRSH) functional and the polarization continuous model (PCM) for simulating the solid-phase environment of OSCs. [42][43][44] The exchange-correlation energy can be calculated as follows:…”

“…The details of calculating the rate constants have been reported in our previous work. 27,35,37,54,55 All quantum chemistry calculations based on DFT and timedependent DFT (TDDFT) in this work were done using the Gaussian 09 package, 56 and the calculations of electrostatic potential (ESP), charge transfer amount (Dq), and charge transfer distance (Dd) were performed using Multiwfn software, 57,58 and the molecular orbital (MO) and ESP maps were drawn using VMD1.9.3. 59 Table 1 The calculated HOMOÀ1, HOMO, LUMO, LUMO+1 levels (in eV) and HOMO-LUMO gap (H-L gap , in eV), as well as the static e s and dynamic e d dielectric constants for PM6, Y6, AQx-2, Y6-T, Y6-2T, Y6-O, Y6-1O, and Y6-2O Based on the optimized geometries, the main torsion angles are labeled in Fig.…”

“…This type of method has been widely used in many previous works and achieved good results. 27,35,37 Hence, the electronic structures and related properties in this work were calculated using the optimally tuned screened range separated hybrid (OTSRSH) functional and the polarization continuous model (PCM) for simulating the solid-phase environment of OSCs. 42–44 The exchange–correlation energy can be calculated as follows:LR and SR are the long-range and short-range interactions terms, respectively, HF X indicates the Hartree–Fock exchange term, and PBE X and PBE C represent the exchange and correlation terms based on the PBE generalized functional, respectively.…”

“…The details of calculating the rate constants have been reported in our previous work. 27,35,37,54,55…”

“…14 In addition to experimental works, the theoretical calculations and simulations, such as molecular dynamics and electronic structure calculations, are also important for development of organic electronics, such as OSCs. 23–27 By modifying the DA 2 D core unit in Y6, Zheng et al inserted thiophylthiophene between the DA 2 D core and the acceptor unit for obtaining BTP4T-4F, and demonstrated that BTP4T-4F is superior to the prototype Y6 based on the calculated dipole moment (Y6: 0.64 D, BTP4T-4F: 1.14 D), absorption spectra (Y6: 498–797 nm, BTP4T-4F: 524–950 nm), and hole (Y6:6.06 × 10 13 s −1 , BTP4T-4F: 1.02 × 10 14 s −1 ) and electron transfer rates (Y6: 2.62 × 10 14 s −1 , BTP4T-4F: 4.58 × 10 14 s −1 ). 28 Based on quantum chemistry calculations, Li et al designed a series of asymmetric NFAs Y6-C, Y6-N, Y6-O, Y6-Se, and Y6-Si by substituting the two S atoms of one thieno[3,2- b ]thiophene unit in Y6 with C, N, O, Se, and Si atoms, respectively.…”