Rationalization of excited state energy transfer in D–π–A porphyrin sensitizers enhancing efficiency in dye-sensitized solar cells. Issue 24 (21st October 2021)

• Record Type: Journal Article
• Authors: Krishna, Jonnadula Venkata Suman; Prasanthkumar, Seelam; Dzeba, Iva; Challuri, Vijay; Naim, Waad; Sauvage, Frédéric; Giribabu, Lingamallu
• Is Part Of: Materials advances. Volume 2:Issue 24(2021)
• Page Start: 7922
• Page End: 7931
• Publication Date: 2021-10-21
• Subjects: 620.11
• DOI: 10.1039/d1ma00614b
• Languages: English
• ISSNs: 2633-5409

Abstract

Abstract : Donor–π–acceptor (D–π–A) porphyrin based photo-sensitizers are extensively utilized in dye sensitized solar cells (DSSCs). Abstract : Donor–π–acceptor (D–π–A) porphyrin based photo-sensitizers are extensively utilized in dye sensitized solar cells (DSSCs). However, investigation on how the intramolecular photoinduced energy/electron transfer influences the device performance is still limited. Herein, we report three new D–π–A porphyrin sensitizers (LG8, LG9 and LG10 ) comprising 3-ethynylfluoranthene as the donor and 2, 1, 3-benzothiadiazole (BTD), 2, 3-diphenylquinoxaline (DPQ), and 2, 3-di(thiophen-2-yl)quinoxaline (DTQ) as auxiliary acceptors. LG8 showed more efficient and red-shifted energy transfer between the donor and acceptors, which translates into a higher power conversion efficiency (PCE). UV-visible absorption and fluorescence spectra revealed a large bathochromic shift and a significant quenching of the donor emission confirming an efficient intramolecular energy transfer from the fluoranthene-linked porphyrin to the auxiliary acceptor benzothiadiazole in LG8 . Density functional theory calculations showed that the LUMO of LG8 and LG10 destabilized and matched with the conduction band edge of the anatase TiO2 nanoparticles. As a result, LG8 and LG10 exhibited the best power conversion efficiency ( η ≈ 3.0%) compared to LG9 ( η = 1.50%) owing to faster electron injection from the dye excited states into the conduction band of TiO2 . This work underlines that the modification of the electron donor and the acceptor in D–π–A porphyrin sensitizers has noticeable influence on the photo-physical properties of π-conjugated systems, thereby affecting device performances.