Effective redox shuttles for polymer gel electrolytes-based quasi-solid-state dye-sensitized solar cells in outdoor and indoor applications: Comprehensive comparison and guidelines

Various redox shuttle-mediated polymer gel electrolytes (PGEs) were utilized individually to fabricate quasi-solid-state (QSS) dye-sensitized solar cells (DSSCs) for outdoor and indoor applications. The power conversion efficiency (PCE) of QSS DSSCs based on I₃⁻/I⁻-mediated PGEs was comparable with liquid electrolyte-devices under both 1-sun and 1000 lux compact fluorescent light (CFL) (compact fluorescent lamp) illuminations. The PCEs for QSS-DSSCs based on cobalt/copper complex-mediated PGEs were not comparable with their liquid electrolyte DSSCs under 1-sun condition, but, comparable, even higher for cobalt complex-mediated PGE devices, under CFL light. The PCE for organic dye-sensitized cobalt PGE devices was in the range of 23%–30% under 200–2000 lux CFL illuminations. The remarkable PCEs of 27.5% and 25.0% were obtained for cobalt and copper complex-mediated PGE-based QSS DSSCs using organic sensitizers, respectively, under 1000 lux CFL light. This result specifies that the mass transport limitation of Co-/Cu-complexes in PGEs can only be applicable for 1-sun illumination, not for ambient lighting. The outstanding efficiency under CFL ambient light and high stability under 50 °C make us optimistic for future commercial utilization of metal-complex-mediated PGE-QSS DSSCs as a safe power source for the internet of things and low-powered autonomous electronic devices.