Multi-faceted investigation of ZnO nanoparticles with 1-ethyl-3-methylimidazolium iodide for enhancing DSSC performance

This study presents a comprehensive experimental and computational investigation of ZnO nanoparticles with 1-ethyl-3-methylimidazolium iodide (EmimI) to enhance the performance of dye-sensitized solar cells (DSSCs). Two distinct ZnO morphologies, star-like (ZnO-S) and plate-like (ZnO-P), were synthesized and characterized. ZnO-P exhibited a higher specific surface area (6.06 m² g⁻¹) and a wider bandgap (3.31 eV) compared to ZnO-S (1.86 m² g⁻¹, 3.19 eV). When integrated into DSSCs with EmimI-based electrolytes, ZnO-P achieved a maximum efficiency of 9.86% after 3 h of dye immersion, while ZnO-S reached 8.38% after 1 h. Molecular dynamics simulations revealed that EmimI enhances iodide ion mobility and suppresses charge recombination by competitively blocking triiodide adsorption sites at the ZnO interface. The simulations also demonstrated strong interactions between Emim⁺ cations and the ZnO surface, optimizing electrolyte penetration and charge transport. These findings provide mechanistic insights into the role of ZnO morphology and EmimI in improving DSSC efficiency, offering a pathway for the design of high-performance solar energy devices.