All-solid-state nanocomposite electrolytes composed of an ionic polymer with polar groups and surface-modified SiO2 nanoparticles for dye-sensitized solar cells

Abstract

Solid-state electrolytes based on ionic polymer (IP)–SiO₂ nanocomposite are prepared for dye-sensitized solar cells (DSCs). An IP with a cationic main chain and polar ester and carbonyl groups is synthesized from 2,3-dichloropropionic acid methyl ester and N,N′-carbonyldiimidazole. SiO₂ nanoparticles are chemically modified by silane coupling agents KH550 and KH570. The polar groups in the IP and on the surface of the modified SiO₂ can facilitate the ionization of iodide in the electrolyte and increase the number of charge carriers. Moreover, according to the principle of ‘like dissolves like’, SiO₂ modified by polar groups can be compatible with the IP and yield a long-term stability for the electrolyte. Eventually, the solid-state electrolyte containing IP and modified SiO₂ achieves a high conductivity of 3.05 mS cm⁻¹. The all-solid-state DSCs with the composite electrolyte have favorable stability and photo-to-current conversion efficiencies of 5.03% at 30 mW cm⁻² and 4.86% at 100 mW cm⁻².