The influence of the metal cation and the filler on the performance of dye-sensitized solar cells using polymer-gel redox electrolytes
(EN)
Chatzivasiloglou, E.
(EN)
Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείας
(EL)
Chatzivasiloglou, E.
(EN)
New composite PEO-based polymer-gel electrolytes were developed, using propylene carbonate (PC) plasticizer and iodide/triiodide (I-/I-3(-)) redox couple. The iodide anion was introduced in the form of the corresponding metal salts: CsI, RbI and LiI and the influence of the metal cation was examined. The non-volatile and high polar character of the PC plasticizer results to excellent ionic conductivity values of the electrolyte samples (up to 1.6 mS cm(-1)), as well as remarkable stability over time. Linear sweep voltametry measurements revealed noticeable triiodide diffusion coefficient values (in the order of 2 x 10(-6) cm s(-1)). The thermograms confirm the amorphicity of the electrolytes (crystallinity values below 20%). All the experimental results showed that the introduction of inorganic titania filler (Degussa P25) into the polymer matrix reduces even more the crystallinity of the samples and enhances the mobility of the redox couple. Nanocrystalline photoelectrochemical solar cells were fabricated with the newly developed composite electrolytes and were tested with I-V measurements. All cells presented high efficiency values for this type of composite electrolytes, with the best performance attained in the case of the PEO-TiO2-PC(CSI/I-3(-)) electrolyte, with overall energy conversion efficiency (eta) of 2.87% under standard AM1.5 simulated solar irradiation. Our results clearly support the redox couple mobility dependence on the cation nature. (C) 2007 Elsevier B.V. All rights reserved.
(EN)
