Effects of side substituents in bithiophene spacer on the performance of dye-sensitized solar cells with cobalt electrolyte.

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From: Solar Energy(Vol. 218)
Publisher: Elsevier Science Publishers
Document Type: Report; Brief article
Length: 324 words

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Abstract :

Keywords Dye-sensitized solar cells; Organic sensitizer; Bithiophene spacer; Side substituent; Cobalt electrolyte Highlights * Alkyl/alkylphenyl as side groups have been incorporated into the bithiophene bridge. * Two new carbazole dyes (CzD2 and CzD3) with these spacers were synthesized. * The effects of side groups on the spectral, electrochemical properties were studied. * Their photovoltaic performance with cobalt electrolyte was also investigated. * CzD3 with the bulkiest side groups in the [pi]-bridge yielded the highest PCE (6.20%). Abstract In order to prevent the inter-molecular aggregation and retard electron recombination, blocking side substituents, i.e. alkyl and alkylphenyl, were incorporated into the bithiophene bridge and two new carbazole-based sensitizers (CzD2 and CzD3) were synthesized. A reference dye (CzD1) comprising bithiophene spacer was also synthesized for comparative purposes. Their photophysical, electrochemical, structural and electronic properties were extensively investigated for highlighting the effects of side substituents. Moreover, their photovoltaic properties were evaluated using cobalt-containing electrolyte. The CzD3 with the bulkiest side group yielded the highest power conversion efficiency (PCE) of 6.20% due to the largest open circuit voltage (Voc) and short circuit photocurrent (Jsc). Furthermore, incident photon-to-current efficiency (IPCE) spectra and electrochemical impedance spectroscopy (EIS) analysis were performed to reveal the impact of side substituents on the performance of devices. Therefore, this work demonstrates that incorporating blocking side groups into the [pi]-bridge is an effective way to obtain high PCEs of sensitized cells with cobalt redox. Author Affiliation: (a) Xi'an Modern Chemistry Research Institute, Xi'an, Shaanxi 710065, PR China (b) School of Chemistry and Chemical Engineering, Pulp & Paper Engineering State Key Laboratory of China, South China University of Technology, Guangzhou 510640, PR China (c) Zhuhai Institute of Advanced Technology Chinese Academy of Sciences, Zhuhai, Guangdong 519000, PR China * Corresponding author. Article History: Received 24 October 2020; Revised 2 March 2021; Accepted 3 March 2021 Byline: Zhi-Sheng Wu [wuzhisheng204@163.com] (a,*), Jie Zhang (a), Wang-Jun Guo (a), Ya-Dong Liu (a), Dan-Yang Wan (a), Jin-Xing Long (b), Zheng-Jian Chen (c)

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Gale Document Number: GALE|A657002970