单晶二氧化钛纳米线的制备及其在柔性染料敏化太阳能电池中的应用

采用强碱水热法制备单晶二氧化钛纳米线(SCTNW),在高压高温和强碱作用下,二氧化钛颗粒的(010)晶面被NaOH溶液侵蚀,生成钛酸钠(Na2Ti4O9);经过酸洗后,生成钛酸水合物(H2Ti4O9·H2O),钛酸水合物之间通过氢键连接成线状;烧结失水后,最终形成SCTNW.通过透射电子显微镜(TEM)、选区电子衍射(SAED)、X射线能量散射谱(EDS)和X射线衍射(XRD)等手段进行表征和测试,分析了SCTNW的形成过程,探讨了水热时间对SCTNW形成的影响;将获得的SCTNW共混在二氧化钛纳米颗粒的胶体中,采用刮涂法在柔性钛箔上制备了染料敏化太阳能电池(DSSC)光阳极,通过扫描电子显微镜(SEM)、交流阻抗谱(EIS)、紫外-可见(UV-Vis)分光光度计和电池光电性能等表征和测试,探讨了SCTNW的共混量对柔性DSSC光电性能的影响.实验结果表明:当共混7.5%(w)的SCTNW时,所制备的柔性DSSC在100mW·cm-2模拟太阳光照下,光电转换效率达到6.48%.     

Stabilities of flexible electrochemical capacitors based on polypyrrole/carbon fibers in different gel electrolytes

Flexible electrochemical capacitors(ECs) are vitally important as the emerging flexible electronics.We have prepared polypyrrole doped with counter ion of Cl-on carbon fibers(PPy-Cl/CFs) via the simple electrochemical deposition method.The flexible ECs based on PPy-Cl/CFs electrodes have been assembled by using H_3PO_4/poly(vinyl alcohol)(PVA),H_2SO_4/PVA,LiClO_4/PVA,KCl/PVA and Li Cl/PVA as gel electrolytes.The capacitive properties of ECs have been systematically evaluated with electrochemical methods.The results show that the cells with H_3PO_4/PVA electrolyte exhibit good cyclic stability(91.5% retention after 15000 cycles) although PPy-Cl/CFs has moderate specific capacitance in H_3PO_4/PVA(41.6 m F·cm~(-1) or 52.0 F·cm~(-3)).However,the ECs in other electrolytes have poor cyclic stability.Further electrochemical analysis reveals that the doping/dedoping processes of PPy-Cl/CFs are different in the five electrolytes,and X-ray photoelectron spectra demonstrate that the ratios of counter anions in PPy's oxidized states to those in reduced states are obviously different when PPy-Cl/CFs are kept in reduced or oxidized states in the five electrolytes.The results also illustrate why the capacitors using H_3PO_4/PVA as electrolyte exhibit good cyclic stability.Furthermore,a light emitting diode(LED) with a threshold voltage of 2.5 V can be lighted by three ECs connected in series.