Application of deep eutectic solvent from phenol and choline chloride in electrolyte to improve stability performance in dye-sensitized solar cells

• Published in: Journal of molecular liquids Vol. 277; pp. 157 - 162
• Main Authors: Nguyen, Phuong Tuyet, Nguyen, Thuy-Duy Thi, Nguyen, Vinh Son, Dang, Diem Thi-Xuan, Le, Hung Minh, Wei, Tzu-Chien, Tran, Phuong Hoang
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.03.2019
• Subjects: Deep eutectic solvent; DFT calculation; Green chemistry; Liquid electrolyte; DFT calculation; Green chemistry; Deep eutectic solvent; Liquid electrolyte
• ISSN: 0167-7322; 1873-3166
• DOI: 10.1016/j.molliq.2018.12.114

In this study, we aim to develop an efficient, eco-friendly and cost-effective electrolyte solvent mixture for Dye-sensitized Solar Cells (DSCs) by using a deep eutectic solvent (DES). A high-purity choline chloride–phenol DES was synthesized and characterized by Fourier-transform infrared and nuclear magnetic resonance spectroscopy; thermogravimetric analysis and differential scanning calorimetry. The resulting product was mixed with acetonitrile, a typical volatile electrolyte solvent, at various ratios for use as electrolyte in DSCs. The photovoltaic parameters (Jsc, Voc, fill factor, efficiency) of these DSC devices were monitored to investigate their long-term performance. The performance of DES-added cells was initially less efficient, but more stable after more than 1000 h, compared to that of the DES-free cells. DES helped to stabilize and improve the photovoltaic performance of DSCs, particularly the short circuit current, due to the effect of the choline and phenol groups of DES binding on the TiO2 surface, as shown by the density functional theory (DFT) calculation. The optimal results were achieved with electrolyte containing 20% DES (efficiency = 6.9% with stable performance for more than 1000 h). [Display omitted] •An eco-friendly DES mixed with liquid electrolyte for stable DSC performance.•Efficiency of DSC with 20% DES increased from 6.92% to 7.75% after 1300 h.•Co-adsorption of choline and phenyl on surface of TiO2 was calculated by the DFT.•The DES helped stabilize the current and improve the voltage of the DSC devices.