Synthesis, photophysical, electrochemical, and DFT examinations of two new organic dye molecules based on phenothiazine and dibenzofuran.

K Periyasamy,G Venkatesh,Sultan Erkan,P Sakthivel,P M Anbarasan,P Vennila,S Kaya,Y Sheena Mary

doi:10.1007/s00894-022-05026-w

Abstract

New dyes were developed and produced utilizing distinct electron donors (phenothiazine and dibenzofuran), a π-spacer, and an electron acceptor of cyanoacetohydrazide, and their structures were studied using FT-IR and NMR spectroscopy. Following the synthesis of dye molecules, the photophysical and photovoltaic characteristics were investigated using experimental and theoretical methods. The photosensitizers have been exposed to electrochemical and optical property experiments in order to study their absorption performance and also molecular orbital energies. The monochromatic optical conversion efficiency of (Z)-N-((5-(10H-phenothiazin-2-yl)furan-2-yl)methylene)-2-cyanoacetohydrazide (PFCH) was found higher than that of (Z)-2-cyano-N'-((5-(dibenzo[b,d]furan-4-yl)furan-2-yl)methylene)acetohydrazide (BFCH), with IPCEs of 58 and 64% for BFCH and PFCH, respectively. According to the photosensitizer molecular energy level diagram, the studied dye molecules have strong thermodynamically advantageous ground and excited-state oxidation potentials for electron injection into the conduction band of titanium oxide. It was observed that the ability to attract electrons correlated favorably with molecular orbital energy. While density functional theory calculations were used to examine molecule geometries, vertical electronic excitations, and frontier molecular orbitals, experimental and computed results were consistent. Natural bond orbital and nonlinear optical properties were also calculated and discussed.

Highlights

According to their low cost, compliance with environmental requirements, and ease of product preparation, dye-sensitized solar cells (DSSCs) based on metal-free organic dyes are gaining popularity at the moment [1,2,3]
Aside from carrying transmissions, the self-assembled layer of dye molecules on the surface of titania in DSCs controls the quantities of solar photons harnessed and charges separated to a noticeable extent, controlling the resulting energy production [1,2,3,4,5]
Metal free-organic dyes with high efficiency contain at least donor and acceptor units connected by a conjugated system to form a D- -A framework which allows intramolecular charge transfer within the system

Summary

Introduction

According to their low cost, compliance with environmental requirements, and ease of product preparation, dye-sensitized solar cells (DSSCs) based on metal-free organic dyes are gaining popularity at the moment [1,2,3]. Only the energies of the electronic transitions S0 S1 (absorption) and S1* S0* (emission) have been calculated directly They assumed that long-range correction has been required at the very least for the TD-DFT method, the 6-311G basis set, and the CAM-B3LYP functional level analysis of these dye compounds. These characteristics are appropriate for potentially efficient electron injection. In the molecular electrostatic potential images of PFCH and BFCH, the colors blue and red show electron deficiency and stronger electron rich regions, respectively, and these dye compounds clearly exhibit the polarization effect. The calculated and experimental 1H and 13C NMR peaks revealed the molecular structure of PFCH and BFCH

Conclusion

Method