Quasi-Solid-State Dye-Sensitized Solar Cells Based on Ru(II) Polypyridine Sensitizers
The Ru(II) polypyridine complexes SA22 and SA25 consisting of anchoring and light harvesting moieties and possessing broad light absorption spectra were used to fabricate and optimize dye-sensitized solar cells (DSSCs). The highly efficient Z960 electrolyte was used as redox-mediator, and the J-V characteristics and incident photon-to-current conversion efficiency (IPCE) data were measured. The solar cells based on these dyes and electrolyte yielded power conversion efficiencies (PCE) of 7% using SA22 and 5% with SA25. The higher-performance sensitizer SA22 was selected to build solar-cell devices, using either the high-thermal-stability Z946 electrolyte or a gel-electrolyte composed of Z946 electrolyte and 2wt% low-molecular-mass organogelator (LMOG) NME-5. The quasi-solid-state electrolyte produced a DSSC with a PCE of 4.7%, whereas that made using Z946 showed 5% efficiency. The quasi-solid-state DSSC was sealed and a stability study was performed using accelerated thermal aging conditions at 70 degrees C for 7days, by which the cell parameters (including PCE, J(sc), V-oc, and FF) retained more than 90% of their original values.