D ‐A‐D‐based Unsymmetrical Thiosquaraine Dye for the Dye‐Sensitized Solar Cells

Alkyl group-wrapped thiosquaraine dye exhibited better light harvesting property than its corresponding oxo-counterpart,that is, squaraine dyes. However, formation of triplet state caused insufficient charge injection process which led to decreased dye-sensitized solar cell device performance. AbstractIn dye-sensitized solar cell, modulating the electronic properties of the sensitizer by varying the donor, π-spacer, acceptor and anchoring groups help optimizing the structure of the dye for better device performance. Here, a donor–acceptor–donor-based unsymmetrical thiosquaraine sensitizer (SQ5S) has been designed and synthesized. Photophysical, electrochemical, theoretical and photovoltaic characterizations ofSQ5S dye have been compared with its oxygen analog,SQ5. The incorporation of the sulfur atom in the acceptor unit ofSQ5S dye showed an intense peak at 688  nm, which was 38 nm of red-shifted and showed the panchromatic light harvesting response with the onset of 850 nm compared withSQ5 dye. The LUMO and HOMO energy levels are well aligned with the conduction band of TiO2 and the redox potential of electrolyte for the charge injection and the dye-regeneration processes, respectively. Photovoltaic efficiency of 1.51% (VOC 610  mV,JSC 3.07  mA cm−2,ff 81%) has been achieved forSQ5S dye, whereasSQ5 showed the  device performance of 5.43% (VOC 723  mV,JSC 9.3  mA cm−2,ff 80%). The decreased device performance forthe dye SQ5S has been attributed to ...

Source: Photochemistry and Photobiology - January 9, 2023 Category: Science Authors: Avinash P. Jadhav, Ambarish Kumar Singh, Ashakiran Maibam, Sailaja Krishnamurty, Kothandam Krishnamoorthy, Jayaraj Nithyanandhan Tags: Special Issue Research Article Source Type: research