School of Electronic Science and Engineering, Southeast University, Nanjing, 210096, China.
Nanoscale. 2011 Feb;3(2):674-7. doi: 10.1039/c0nr00591f. Epub 2010 Dec 6.
An efficient photoelectrode is fabricated by sequentially assembling 2.5 nm and 3.5 nm CdSe quantum dots (QDs) onto a TiO2 film. As revealed by UV-vis absorption spectroscopy, two sizes of CdSe QD can be effectively adsorbed on the TiO2 film. With a broader light absorption range and better coverage of CdSe QDs on the TiO2 film, a power conversion efficiency of 1.26% has been achieved for the TiO2/CdSe QD (2.5 nm)/CdSe QD (3.5 nm) cell under the illumination of one Sun (AM 1.5G, 100 mW cm(-2)). Electrochemical impedance spectroscopy shows that the electron lifetime for the device based on TiO2/CdSe QD (2.5 nm)/CdSe QD (3.5 nm) is longer than that for devices based on TiO2/CdSe QD (2.5 nm) and TiO2/CdSe QD (3.5 nm), indicating that the charge recombination at the interface is reduced by sensitizing with two kinds of CdSe QDs.
通过将 2.5nm 和 3.5nm 的 CdSe 量子点（QD）依次组装到 TiO2 薄膜上，制备了一种高效的光电电极。紫外可见吸收光谱表明，两种尺寸的 CdSe QD 可以有效地吸附在 TiO2 薄膜上。由于 CdSe QD 在 TiO2 薄膜上的光吸收范围更广且覆盖更好，因此在 1 个太阳（AM 1.5G，100mWcm(-2)）的照射下，TiO2/CdSe QD（2.5nm）/CdSe QD（3.5nm）电池的功率转换效率达到了 1.26%。电化学阻抗谱表明，基于 TiO2/CdSe QD（2.5nm）/CdSe QD（3.5nm）的器件的电子寿命长于基于 TiO2/CdSe QD（2.5nm）和 TiO2/CdSe QD（3.5nm）的器件，这表明通过两种 CdSe QD 的敏化作用，减少了界面处的电荷复合。
