Prof. Marsan 小組與Grätzel在今年解決二個染敏電池的老問題：
(1)電解質：三碘離子與碘離子所組成的電解液會腐蝕陰極上的銀線，而且碘液本身在可見光部份具有高的吸光係數會降低可用的光子量。此外，因為碘液本來的化學電位，使的大部分的DSSC的電壓約為0.7 V附近。
(2)白金電極，白金的價格昂貴，而且現階段以使用濺鍍和燒結法為主。但對於導電塑膠材料而言，加熱的溫度無法太高，白金不易附著其上。
因為Marson小組發展出(1)非碘液的電解質，其效率高達6.4%；(2)非白金電極，以CoS來取代白金，在ITO/PEN的系統中高達7%。
資料來源：Nature Chemistry ；JACS comm.
Abstract:
(1)
Dye-sensitized solar cells (DSCs) have achieved impressive conversion efficiencies for solar energy of over 11% with an electrolyte that contains triiodide/iodide as a redox couple. Although triiodide/iodide redox couples work efficiently in DSCs, they suffer from two major disadvantages: electrolytes that contain triiodide/iodide corrode electrical contacts made of silver (which reduces the options for the scale up of DSCs to module size) and triiodide partially absorbs visible light. Here, we present a new disulfide/thiolate redox couple that has negligible absorption in the visible spectral range, a very attractive feature for flexible DSCs that use transparent conductors as current collectors. Using this novel, iodide-free redox electrolyte in conjunction with a sensitized heterojunction, we achieved an unprecedented efficiency of 6.4% under standard illumination test conditions. This novel redox couple offers a viable pathway to develop efficient DSCs with attractive properties for scale up and practical applications.
(2)
In summary, we have demonstrated, for the first time, that CoS is very effective in catalyzing the reduction of triiodide to iodide in a DSC, superseding the performance of Pt as an electrocatalyst.
For the first time, CoS deposited ITO/PEN films were used as the counter electrodes in DSCs yielding 6.5% efficiency under full sunlight in conjunction with a Z907 sensitizer and an eutectic melt electrolyte. Remarkable cell stability under prolonged light soaking and thermal stress was demonstrated rendering CoS an extremely interesting candidate to replace Pt in photoelectrochemical cells employing the iodide/triiodide redox couple. This breakthrough will contribute to lowering the cost of the DSC, fostering large-scale lightweight outdoor applications of mesoscopic sensitized solar cells.
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