Four hemicyanine derivatives, 2-[4-(N-ethyl-N-carboxyethyl)amino]phenylethenyl-1,3,3-trimethyl-3H-indolium iodide (BIDC1), 2-[4-(N,N-dicarboxyethyl)amino]phenylethenyl-1,3,3-trimethyl-3H-indolium iodide (BIDC2), 2-[4-(N-ethyl-N-carboxyethyl)amino]phenylethenyl-1,1,3-trimethyl-1H-benz[e]indolium iodide (BIDC3) and 2-[4-(N,N-dicarboxyethyl)amino]phenylethenyl-1,1,3-trimethyl-1H-benz[e]indolium iodide (BIDC4), have been synthesized and identified with regard to their structures and electrochemical properties. It is found that the absorption spectra of BIDC3 and BIDC4 are broader than that of BIDC1 and BIDC2 because the former two have one more benzene ring on the electron acceptor side. Upon adsorption on a TiO2 electrode, the absorption spectra of the four BIDC dyes are all broadened forward to both red and blue sides compared with their respective spectra in ethanol solution. BIDC2 (or BIDC4), bearing two carboxyl groups, has about two (or three) times more adsorption and a broader absorption spectrum on TiO2 film compared with BIDC1 (or BIDC3), which consequently leads to a better light-to-electricity conversion property. Among the four hemicyanine dyes, BIDC4 generated the highest photoelectric conversion yield of 4.9%, with a short-circuit photocurrent of 21.4 mA cm−2, an open-circuit voltage of 424 mV, and a fill factor of 0.49 under irradiation with 90.0 mW cm−2 white light from a Xe lamp.
合成了 2-[4-(N,N-二羧乙基)
氨基]苯基
乙烯基-1,1,3-三甲基-1H-苯并[e]
吲哚鎓
碘化物(BIDC3)和 2-[4-(N,N-二羧乙基)
氨基]苯基
乙烯基-1,1,3-三甲基-1H-苯并[e]
吲哚鎓
碘化物(BIDC4),并鉴定了它们的结构和电
化学性质。研究发现,BIDC3 和 BIDC4 的吸收光谱比 BIDC1 和 BIDC2 更宽,这是因为前两者的电子受体侧多了一个苯环。吸附到
二氧化钛电极上后,四种 BIDC
染料的吸收光谱与它们在
乙醇溶液中的光谱相比,都向红色和蓝色两侧拓宽。与 BIDC1(或 BIDC3)相比,带有两个羧基的 BIDC2(或 BIDC4)在
二氧化钛薄膜上的吸附量增加了约两倍(或三倍),吸收光谱也更宽,因此光电转换性能更好。在四种半
氰基
染料中,BIDC4 的光电转换率最高,达到 4.9%,在
氙灯 90.0 mW cm-2 的白光照射下,短路光电流为 21.4 mA cm-2,开路电压为 424 mV,填充因子为 0.49。