The influence of driving force on intramolecular electron transfer: A theoretical study of subphthalocyanine‐AzaBODIPY‐C₆₀ supramolecular triad

Abstract

The driving force of electron transfer is one of important factors for initializing inter‐ and intramolecular charge separation. In this work, the main goal is to understand how driving force determines electron transfer pathway in subphthalocyanine‐AzaBODIPY‐C60 supramolecular triad. Experimental observations have suggested that there are only two intramolecular charge transfer states (subPC+‐AzaBODIPY−‐C60 and subPC+‐AzaBODIPY‐C60−) after photon absorption, where subPC is the donor. Through the calculations by using tuned long range corrected density functionals with polarizable continuum model, we find two more new intramolecular charge transfer states: subPC−‐AzaBODIPY+‐C60 and subPC‐AzaBODIPY+‐C60−, where AzaBODIPY is the donor. We compare the HOMO/LUMO energy of subPC, AzaBODIPY, and C60 monomers to their corresponding orbital energy in the triad. The results indicate that the driving force (HOMO/LUMO energy offsets) is not enough for electron transfer from AzaBODIPY to subPC or C60, which can explain why subPC−‐AzaBODIPY+‐C60 and subPC‐AzaBODIPY+‐C60− intramolecular charge transfer states cannot be observed in the experiment. In addition, this work may provide a simple and practical method to find the intramolecular charge transport pathway of a supramolecule.

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

“…The DHL value closely relates to the driving force of CR and charge transfer energy that determines V OC . 23,58 More interestingly, the difference in DHL among IM-4F, IT-4F and IO-4F OPV systems agree well with the e  V OC difference. For instance, the increase in DHL from IT-4F to IO-4F OPV systems (0.41 eV) corresponds to an increase in e  V OC from 0.856 to 1.26 eV.…”

Recent advances in subphthalocyanines and related subporphyrinoids

“…Geometry, electronic structure, electrochemical and spectroscopic features of SubPcs have been thoroughly investigated by theoretical calculations. 211–233 A detailed study on a series of three SubPc-Cl derivatives bearing different peripheral substituents ( i.e. perhydrogenated, trinitro- and tri- t -butyl SubPc) at Hartree–Fock (HF) and density functional theory (DFT) levels using STO-3G and 6-31G basis sets has been reported by Ferro et al 211 The calculated geometries of the unsubstituted derivative were found to be in accordance with the experimental data from X-ray diffraction studies, and no substantial changes were detected with respect to the substituted derivatives.…”

Theoretical Study on Functionalizing A–D–A Type Non‐Fullerene Acceptor by Fused Rings and Side Chains for Organic Solar Cells

“…[ 49 ] The ΔHL value closely relates to the CT energy that determines V OC . [ 33,51 ] The trend of ΔHL is consistent with that of V OC . The experimentally measured V OC for OSCs based IDTIC and IDTTIC were 0.84 and 0.92 V, [ 16 ] respectively, and the ΔHL for IDTIC and IDTTIC systems were 2.158 and 2.187 eV, respectively.…”

“…The great LUMO/HOMO energy offset between electron donor and acceptor in heterojunction provides sufficient driving force for ED. [50] For instance, the ΔHL of PBDB-T:ITIC-OE and PBDB-T:ITIC are 2.113 and 2.133 eV, respectively, corresponding to electron transfer efficiency of 74% and 90%, respectively. [49] The ΔHL value closely relates to the CT energy that determines V OC .…”