Tuning of end-groups in diketopyrrolopyrrole-based acceptors molecules for organic photovoltaics

Abstract

In this computational approach, four small novel acceptor molecules of A2-D-A1-D-A2 type have been designed (S1-S4) by the replacement of terminal acceptor groups (A2) of R molecule with four different types of electron accepting-units. The photovoltaic aspects of molecules have been studied by using DFT based method i.e. B3LYP/6–31 G (d, p). The energy level of ground and excited state, bandgap (Egap), excitation energy, transition density matrix (TDM), absorption maxima (λmax), light-harvesting efficiency (LHE), the density of states (DOS), open circuit voltage (VOC) and many other optoelectronic properties of molecules have been investigated in this research. Out of all the newly suggested molecules, S2 has exhibited the highest red-shift in λmax (815 nm), the lowest excitation energy (1.52 eV), small band gap and ionization potential, and the highest oscillator strength (1.97). The VOC of the studied acceptor molecules was calculated with regard to the PTB7-Th donor, and the findings showed that all of the newly suggested molecules displayed a higher VOC and a greater FF than that of R molecule. Consequently, the findings of these calculations show that our computational investigations give profound insights to support a realistic implementation of OSCs with the accepted acceptor molecules examined.

Keywords

• Density Functional Theory
• Small molecules solar cell
• Non-fullerene optoelectronics
• And diketopyrrolopyrrole-based small molecules