Graphene Oxide Sponge as Nanofillers in Printable Electrolytes in High-Performance Quasi-Solid-State Dye-Sensitized Solar Cells
Venkatesan, S; Darlim, ES; Tsai, MH ; Teng, H; Lee, YL
A graphene oxide sponge (GOS) is utilized for the first time as a nanofiller (NF) in printable electrolytes (PEs) based on poly(ethylene oxide) and poly(vinylidene fluoride) for quasi-solid-state dye-sensitized solar cells (QSDSSCs). The effects of the various concentrations of GOS NFs on the ion diffusivity and conductivity of electrolytes and the performance of the QS-DSSCs are studied. The results show that the presence of GOS NFs significantly increases the diffusivity and conductivity of the Pes. The introduction of 1.5wt % of GOS NFs decreases the charge-transfer resistance at the Pt-counter electrode/electrolyte interface (Rpt) and increases the recombination resistance at the photoelectrode/electrolyte interface (Rct). QS-DSSC utilizing 1.5 wt % GOS NFs can achieve an energy conversion efficiency (8.78%) higher than that found for their liquid counterpart and other reported polymer gel electrolytes/GO NFs based DSSCs. The high energy conversion efficiency is a consequence of the increase in both the open-circuit potential (Voc) and fill factor with a slight decrease in current density (Jsc). The cell efficiency can retain 86% of its initial value after a 500 h stability test at 60 °C under dark conditions. The long-term stability of the QS-DSSC with GOS NFs is higher than that without NFs. This result indicates that the GOS NFs do not cause dye-desorption from the photoanode in a long-term stability test, which infers a superior performance of GOS NFs as compared to TiO2 NFs in terms of increasing the efficiency and long-term stability of QS-DSSCs.
以海綿狀氧化石墨烯作為可印刷式電解質的奈米填充劑並應用在高效能擬固態染料敏化太陽能電池
在擬固態染料敏化太陽能電池中,海綿狀氧化石墨烯(GOS)首次被應用在含有聚乙二醇和聚偏二氟乙烯膠化劑的印刷型電解質中當作奈米填充劑。本研究中探討不同濃度GOS填充劑對於電解質之離子擴散度與導電率,以及對電池性能之影響。實驗結果顯示,GOS的使用會顯著增加電解質的擴散度與導電率。在電解質中加入1.5 wt.%的GOS會降低電池中白金對電極與電解質界面的電荷轉移阻力,同時增加光電極與電解質界面的再結合阻力;使用此電解質的擬固態染敏電池,相對於液態元件及其他已發表且使用含有石墨烯材料的膠態電池,具有更高的光電轉換效率(8.78%),而此高效能主要是開路電壓和填充因子的增加,以及電流密度略微降低之結果。此外,經過500小時於黑暗中60oC的穩定性測試之後,電池效率仍可保持其初始值的86%。具有GOS填充劑的擬固態電池相較於無填充劑之元件可呈現更佳的長效穩定性,此結果顯示GOS填充劑在測試中不會造成光電極上的染料脫附現象,因而可推斷針對擬固態染敏電池之效率與穩定性等方面,GOS相較於二氧化鈦具有更優異之填充劑表現。