A novel charge extraction method for the study of electron transport and interfacial transfer in dye sensitised nanocrystalline solar cells
A novel charge extraction method for the study of electron transport and interfacial transfer in dye sensitised nanocrystalline solar cells
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DOI：
10.1016/s1388-2481(00)00097-7
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发表时间：
2000-09-01
影响因子：
5.4
通讯作者：
Wijayantha, KGU
中科院分区：
文献类型：
--
作者：
Duffy, NW;Peter, LM;Wijayantha, KGU
提出了一种新的电荷提取方法，用于研究染料敏化纳米晶电池（Gratzel电池）中光生电子的输运、俘获和反反应。在开路下照射电池，直到达到稳态，其中光生速率和电子与三碘化物的反反应速率相等。然后中断照明，并且在使用固态开关使电池短路之前，允许电子密度在黑暗中衰减给定的时间。对于高效率电池，在短路时测量的积分电流与膜中剩余的电子电荷密切对应。需要小的修正来解释反反应和基底充电。照明中断和短路电荷提取之间的延迟时间系统地变化，以跟随电子浓度的衰减。电子电荷随时间变化的分析表明，电子与I-3（-）的反反应在电子密度上是二级反应，这与I-2（-）作为中间体的形成是一致的。同时测量的电荷和光电压衰减曲线表明，陷阱态密度随陷阱深度呈指数下降。(C)2000年由Elsevier Science S.A.出版。
A novel charge extraction method has been developed to study the transport, trapping and back reaction of photogenerated electrons in dye sensitised nanocrystalline cells (Gratzel cells). The cell is illuminated at open circuit until a steady state is reached in which the rates of photogeneration and of back reaction of electrons with tri-iodide are equal. The illumination is then interrupted, and the electron density is allowed to decay for a given time in the dark before short circuiting the cell using a solid state switch. For high efficiency cells, the integrated current measured at short circuit corresponds closely to the remaining electronic charge in the film. Small corrections are required to account for back reaction and substrate charging. The delay time between interruption of the illumination and short circuit charge extraction is varied systematically to follow the decay of electron concentration. Analysis of the time dependence of the electron charge indicates that the back reaction of electrons with I-3(-) is second order in electron density, which is consistent with the formation of I-2(-) as an intermediate. Simultaneous measurement of the charge and photovoltage decay curves shows that the density of trap states decreases exponentially with trap depth. (C) 2000 Published by Elsevier Science S.A.