Designing of Thiophene [3, 2-b] Pyrrole Ring-Based NFAs for High-Performance Electron Transport Materials: A DFT Study

Abstract

Among the blended components of a photoactive layer in organic photovoltaic (OPV) cells, the acceptor is of high importance. This importance is attributed to its increased ability to withdraw electrons toward itself for their effective transport toward the respective electrode. In this research work, seven new nonfullerene acceptors were designed for their possible utilization in the OPVs. These molecules were designed through side-chain engineering of the PTBTP-4F molecule, with its fused pyrrole ringbased donor core and different strongly electron-withdrawing acceptors. To elucidate their effectiveness, the band gaps, absorption characteristics, chemical reactivity indices, and photovoltaic parameters of all of the architecture molecules were compared with the reference. Through various computational software, transition density matrices, graphs of absorption, and density of states were also plotted for these molecules. From some chemical reactivity indices and electron mobility values, it was proposed that our newly designed molecules could be better electrontransporting materials than the reference. Among all, TP1, due to its most stabilized frontier molecular orbitals, lowest band gap and excitation energies, highest absorption maxima in both the solvent and gas medium, least hardness, highest ionization potential, superior electron affinity, lowest electron reorganization energy, as well as highest rate constant of charge hopping, seemed to be the best molecule in terms of its electron-withdrawing abilities in the photoactive layer blend. In addition, in terms of all of the photovoltaic parameters, TP4−TP7 was perceived to be better suited in comparison to TPR. Thus, all our suggested molecules could act as superior acceptors to TPR.

High-Efficiency and Low-Energy-Loss Organic Solar Cells Enabled by Tuning the End Group Modification of the Terthiophene-Based Acceptor Molecules to Enhance Photovoltaic Properties

“…The density of state visualized and calculated by PyMOlyze1.1 software provides us with the contribution of each orbital in the radiation absorption. While TDM was plotted by Multiwfn 3.7 software, plots provide information about charge delocalization and the localization of proposed molecules. The Marcus theory has been used to calculate the intermolecular and intramolecular charge movements, and the reorganization energy has been examined.…”

Theoretical Study on the Construction of Efficient Electron Transport Materials with A–DA′D–A Structures toward Efficient Perovskite Solar Cells

“…In addition, the conversion efficiency of NDI-based molecules as ETM of PSCs is still low and requires further improvement by optimizing the structure of molecular and electronic features. In recent years, the partial binding of electron donors (D) and electron acceptors (A) into conjugated systems have proved to be effective way due to the high charge mobility and effects of self-doping. − Since A–D–A molecules are easily synthesized, have low-lying LUMO energy levels, and exhibit excellent electron mobility, they have been explored extensively in organic solar cells. − Among them, the D unit can be extended to more complex DA′D cores. The basic construction strategies of this A–D–A structure involve designing and optimizing the combination of core units, terminal units, and side chains.…”