Understanding the Electronic Interactions, Vertical Excitation Analysis, and the Photovoltaic Properties of 5-(2-ethylhexyl)-1,3-di(furan-2-yl)-4H-thieno[3,4-c]pyrrole-4,6-dione

Abstract

Organic photovoltaic (OPV) are a promising new class of photovoltaic as they offer several advantageous features including large surface area to volume ratio, low cost, lightweight properties, and durability. The limitation of OPV that prevented their adoption for use in the past was their low power conversion efficiency (PCE) but that drawback has been solved by the development of the donor-acceptor-donor (D-A-D) system with high conversion efficiencies. Herein, 5-(2-ethylhexyl)-1,3-di (furan-2-yl)-4H-thieno [3,4-c]pyrrole-4,6(5H)-dione (FTPF), a donor-acceptor-donor monomer was investigated for its optoelectronic, excited state, and photovoltaic properties using a density functional theory (DFT) and time-dependent density function theory (TD-DFT) at the B3LYP/6-31+G(d,p) theoretical method. The spectral analysis (FT-IR, UV-vis, and NMR), electronic molecular properties, natural bonding orbitals (MOs and NBOs) analyses, and excitation were studied at this level in gas, hexane, DMF, and THF. The UV-Vis spectrum showed that FTPF exhibited mono-absorption in non-polar gas and hexane, but dual absorptions in polar solvents (DMF and THF) having maximum wavelength (λmax) at 351, 359, 371 and 373 nm in gas, hexane, THF, and DMF respectively, showing a major red shift as solvent became polar. The hole-electron excitation studies of the first five singlet states: S0→S1/S2/S3/S4/S5 in gas and DMF phases showed that S0→S1 is a delocalized π→π* Rydberg excitations originating from the D-A-D C=C π bonds, S0→S2 is π→π* local excitation, while S0→S3 in water occurred as an n→π* from the carbonyl and azolide groups of the acceptor unit, but n→π* charge transfer (CT) in DMF. The S0→S5 in water and S0→S4 are n→π* LE type excitations, while S0→S5 in DMF conformed to a delocalized π→π* excitation extended over the D-A-D conjugated backbone. FTPF provided efficient electron injection in all studied solvent; showing that FTPF is a sure-bet for opto-electronic application.

Interaction of 5-Fluorouracil on the Surfaces of Pristine and Functionalized Ca12O12 Nanocages: An Intuition from DFT

“…Natural bond orbital analysis, developed by Weinhold et al, is an important technique that unravels information on the electron distribution within the intermolecular bonds between atomic species and gives insight into the charge transfer pattern in the studied systems. However, NBO analysis provides adequate knowledge on the bonding orbital type, occupancy level, and also the nature of interactions present in the valence space between the virtual and occupied Lewis orbitals. , There is a loss of electron occupancy from localized filled Lewis NBO into an empty antibonding non-Lewis orbital because of the nature of the interaction . Calculated results for the interaction between the drug and the nanocage are presented in Table .…”

“… 74 , 75 There is a loss of electron occupancy from localized filled Lewis NBO into an empty antibonding non-Lewis orbital because of the nature of the interaction. 76 Calculated results for the interaction between the drug and the nanocage are presented in Table 4 . From the NBO natural charges, pristine Ca 12 O 12 has its Ca atoms to be electron-deficient (1.803 e ), while O atoms are electron-rich (−1.803 e ).…”