Towards green, efficient and stable quantum-dot-sensitized solar cells through nature-inspired biopolymer modified electrolyte

• Published in: Electrochimica acta Vol. 391; p. 138972
• Main Authors: Rasal, Akash S., Korupalli, Chiranjeevi, Getachew, Girum, Chou, Tzung-Han, Lee, Ting-Ying, Ghule, Anil V., Chang, Jia-Yaw
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 20.09.2021
• Subjects: Antioxidant; Bio-polymer additive; Electrolyte; Quantum dots; Solar cells; FTO; DLS; Bio-polymer additive; PDA; R; QD; NADH; DSSCDSSC; XPS; Cys; QDSSCs; Solar cells; NBT; Quantum dots; OCVD; Antioxidant; P-PDA; EIS; TGA; PCE; CV; Electrolyte; Se-PDA; PMS; DA
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2021.138972

•Nature-Inspired Biopolymer, Polydopamine (PDA) serves as an efficient and stable additive to polysulfide electrolyte•For the first time, PDA-based additives are used to control the electron-hole recombination process in quantum dot sensitized solar cells (QDSSCs).•PDA-based additives are effective in the reduction of the Sn2− to S2− species of polysulfide electrolyte.•Higher photovoltaic efficiencies and long-term stabilities are achieved with PDA-based additives compared to that of pristine polysulfide electrolyte. Modifying the polysulfide electrolytes with the polymer additives to suppress the electron-hole recombination process has been proven to be rationally a simple and effective strategy to accomplish efficient and stable quantum dot-sensitized solar cells (QDSSCs). However, compared to the extensively studied organic or inorganic polymer additives, the use of the natural bio-polymer additives in the electrolyte has been less concerned. In this respect, a novel nature-inspired biopolymer, polydopamine (PDA)-based additives are introduced to the polysulfide electrolyte to achieve efficient and stable QDSSCs. Further, the surface and chemical properties of PDA are enriched by functionalization with PEG-NH2 (P-PDA) and subsequent Se doping (Se-PDA). This is the first-ever report using PDA-based additives to regulate the electron-hole recombination dynamics at the TiO2/QDs/electrolyte interface. The QDSSCs fabricated with P-PDA and Se-PDA electrolytes have accomplished higher conversion efficiencies of 7.83% and 8.59%, respectively, compared with that of reference electrolyte (7.62%). Most importantly, PDA-based additives have considerably improved the performance stability of the QDSSCs. The devices that are fabricated with P-PDA and Se-PDA electrolytes displayed 91% and 79% of their original performance after 60 h, respectively; whereas, the liquid electrolyte retained only 11% of its initial performance in the same duration. The long-term stabilities of PDA-based additives are possibly due to the antioxidative property of PDA which may feasibly neutralize the light-induced radicals (R•) in the device. Overall, the novelty of the present work is based on the fabrication of efficient and stable QDSSCs through a cost-efficient and environmentally friendly bio-polymer additive to polysulfide electrolytes. [Display omitted]