Terminal Modulation in Search of a Balance between Hole Transport and Electron Transfer at the Interface for BODIPY-Based Organic Solar Cells

Abstract

Organic solar cells (OSCs) have made rapid advances in power conversion efficiency during the past decades, which is boosted partly by the various designs of new materials, especially in donor materials. However, as one kind of famous fluorescence materials, 4,4′-difluoro-4-bora-3a,4a-diaza-s-indacenes (BODIPY)based materials are seldom applied in OSCs until its conjugated molecules have been synthesized and designed as donors recently.Here, we designed a series of BODIPY molecules by terminal modulation based on a reported one and probed their potential promising properties for donor materials in OSCs by means of quantum chemical calculations and molecular dynamics simulations. Many important parameters pertaining to short circuit density (J SC ) such as capability of light absorption, dipole moment transition between the ground and excited states, hole mobility evaluated on the basis of predicted crystal structures, charge-transfer rate (k inter-CT ), and charge recombination rate (k inter-CR ) computed based on local interface geometries of donor/fullerene selected from molecular dynamics simulation results except for some elemental properties were investigated in detail from a theoretical perspective. The results reveal that the terminal modulation through increasing π-conjugation length is feasible. Notably, it is beneficial to balance the ability of hole transport and charge transfer when considering the π-conjugation length and planarity of donor materials. Finally, we hope that this work can pave the way to the design of potential near-infrared donor materials.

Halogenation of the Side Chains in Donor‐Acceptor Based Small Molecules for Photovoltaic Applications: Energetics and Charge‐Transfer Properties from DFT/TDDFT Studies

“…[70,[97][98] In our case, on the other hand, a single value for l is used for both CT and CR processes, and this procedure has worked well for other systems, as shown in the literature. [99][100][101] l values of A1-A12/PCBM systems are in the range of 0.50-0.53 eV, and hence, ls for parent SMs and halogen-substituted SMs are very close to each other.…”

PCDTBT8‐Doped PffBT4T‐2OD‐Based Ternary Solar Cells with Enhanced Open‐Circuit Voltage, Fill Factor, and Charge Separation Efficiency

“…Higher EAs can contribute to the more accessible combination of holes and electrons, so a higher EA enables electron injection. [ 31,32 ] The IPs and EAs of the PffBT4T‐2OD and PCDTBT8 molecules with different units are shown in Table 2 . PffBT4T‐2OD has a relatively low IP and a relatively high EA, indicating that PffBT4T‐2OD is more favorable for electron and hole injection than PCDTBT8.…”

Theoretical Insight into Multiple Charge-Transfer Mechanisms at the P3HT/Nonfullerenes Interface in Organic Solar Cells

“…Another crucial factor relating to the final rate in Marcus theory is the electronic coupling ( V ). As in our previous works, ,, the site-energy corrected method and generalized Mulliken–Hush method was, respectively, used to calculate V for charge transfer and recombination processes. The two methods were carried out in ADF and Q-Chem 4.0 software, respectively.…”