Designing of high‐performance dye‐sensitized solar cells by using a new electrolyte based on deep eutectic solvents

The present research is aimed to develop an efficient electrolyte based on deep eutectic solvents (DESs) for dye-sensitized solar cells (DSSCs). In this regard, the performance of the propylene carbonate (PC) and tetrabutylammonium iodide (TBAI) based DES (PC/TBAI-DES) as a new electrolyte solvent for DSSCs is evaluated for the first time. Herein, the effects of various electrolyte components, namely the amount of acetonitrile (AN), iodine, and 1-ethyl-3-methylimidazolium iodide (EmimI), are investigated. The optimal conditions are achieved with an electrolyte composition of 0.1 M of iodine and EmimI in a binary mixture of PC/TBAI-DES and AN (volume ratio 80:20). The DSSCs based on this electrolyte attained a significant conversion efficiency of 10.04% (Jsc = 21.94 mA cm2, Voc = 0.78 V, and FF = 0.58) under 1 sun (AM 1.5) illumination. Moreover, a detailed view of the molecular arrangement of PC/TBAI-DES solution near the titanium dioxide and platinum solid surfaces as electrodes of DSSCs is investigated using molecular dynamics simulations. Besides, the interaction parameters between TBAI ion pair and PC molecule are determined through density functional theory.