Pyrazolone-based charge transport materials: Design, synthesis, DFT predictions, and application in organic solar cell

Abstract

This study presents the design and synthesis of new pyrazolone-based materials featuring anthracene, pyrazolone, fluorene, and pyrene terminal groups, utilizing a cost-efficient synthetic route through HATU-assisted amide coupling reactions. The synthesized PY series structures were characterized using NMR, FT-IR, mass spectrometry, elemental analysis, and thermal analysis techniques, demonstrating thermal stability up to 230 degrees C. Optical properties were assessed via UV-Vis spectroscopy, fluorescence, and cyclic voltammetry (CV). The CV analysis indicated reduction potentials (Ered) of-1.50/-1.26 V for PY-II and-1.39/-1.12 V for PY-V. Density functional theory (DFT) calculations employing the B3LYP functional and the 6-311 + +G(d,p) basis set were conducted to analyse the electronic structure and optoelectronic properties of the PY series. Notably, the band gaps of PY-II and PY-V were determined to be 3.332 and 3.374 eV, with low electron reorganization energies (lambda e) of 0.332 and 0.425 eV, respectively, indicating their potential as it-conjugated building blocks. The photovoltaic performance of bulk-heterojunction organic solar cells (OSCs) fabricated with the ITO/ZnO/PTB7:PY series/ MoO3/Al configuration demonstrated improved fill factors (FF) of 2.3 and 2.5 for PY-II and PY-V, respectively. The findings of this paper highlight the potential of pyrazolone-based compounds as promising candidates for future applications in organic photovoltaics.