双染料复合敏化SnO_2纳米多孔膜光电极的研究

Dye Cosensitization of Nanoporous SnO 2 Photoelectrode

研究 了五甲川 菁和联吡 啶钌双 染料复合 敏化 Ｓｎ Ｏ２ 纳米 结构 电极 的光 电化 学行 为． 结果表明， 五甲川菁 在５５０ ～７ ００ ｎ ｍ 范围 有强吸 收带，而 联吡啶钌 在４００ ～６ ００ ｎ ｍ 吸光 性好， 它们 在电极表面的 共吸附使 吸 光 范 围 几 乎 覆 盖 整 个 可 见 和 近红 外 光 区 ． 它 们 的 激 发 态 能级 为 － ０９１ Ｖ（ ｖｓ Ｎ Ｈ Ｅ） 和 － ０６ Ｖ（ ｖｓ Ｎ Ｈ Ｅ） ，都高 于 Ｓｎ Ｏ２ 纳 米粒 子的 导 带位 置， 有利 于它 们 的激 发态 电 子注入 Ｓｎ Ｏ２ 纳米粒 子的导 带，即 各自 吸收不 同波 长范围 的光， 共同产 生阳 极光电 流． 因而 这种双 染料复合敏 化比单一 五甲川 菁染料或 联吡啶钌 敏化效 果有更显 著的 提高， 同时 光电 转化 率得 到明 显改善，最 高单色光 量子转换 效率（ Ｉ Ｐ Ｃ Ｅ） 可达 ６８ ％

The photoelectrochemical behavior of the nanostructure SnO 2 porous film cosensitized by a cyanine dye (PMC) and cis di(thiocyanato)bis(2,2′ bipyridyl 4,4′ dicarboxylate)ruthenium(Ⅱ) dye (RuL 2(SCN) 2) have been investigated. The ground state level and the excited state level of the dyes were determined by cyclic voltammetry and optical absorption spectroscopy. The results showed that the excited state levels of both dyes matched the conduction band edge of SnO 2 nanoparticle. The optical absorption band of PMC situates in the region of 550 to 700 nm and that of RuL 2(SCN) 2 in the region of 400 to 600 nm. Therefore the cosensitization of these two dyes can widen the optical absorption region. As a result, the photocurrent intensity of nanostructure SnO 2 electrode was increased obviously by co sensitization in both visible and near infra red regions. Consequently the light to electricity conversion efficiency was improved evidently. The maximum value of IPCE has reached 68%.