Development and investigation of new organic electrolytes and complementary counter electrodes for dye sensitized solar cells / by Dalal Aref NourelDine.

Abstract

The aim of this thesis was to find alternative redox shuttles (electrolyte systems) to be used effectively in a DSSC. We were able to synthesize a novel thione -disulfide redox shuttle based on 1-methyl-3-propyl ΓÇô imidazole-2-thione (T) and its oxidized form 2,2ΓÇÖ-dithiobis(1-methyl-3-propyl-2-imidazolinium) ditriflate (DT), and to incorporate it in a DSSC. In addition, we investigated the use of platinum (Pt), cobalt sulfide (CoS), Nickel sulfide (NiS) , copper sulfide(Cu2S) , tungsten oxide (WO3), poly-(3,4-ethylenedioxythiophene) (PEDOT), and multi-walled carbon nanotubes webs (MWCNT webs) deposited on fluorine doped tin oxide (FTO) substrate as complementary counter electrodes for the efficient regeneration of the newly and to be developed electrolyte system. The electro activity of different counter electrodes (CEs) has been evaluated by means of measuring JΓÇôV curves, Tafel plots and impedance spectroscopy. Among the CEs investigated CoS and MWCNT webs based CEΓÇÖs showed much better electro activity towards the regeneration of the electrolyte at the cathode. An efficiency of ╬╖ = 4.12percent has been attained in a DSSC with 20 layers of MWCNT webs, whereas by using a CoS based CE a slightly lower efficiency (╬╖ = 3.99percent) was measured. These results were attributed to the high surface area and electrocatalytic activity of the MWCNT webs.