Photoanodic properties greatly determine the overall performance of quantum-dot-sensitized solar cells（QDSCs）. In the present report, the microdynamic behaviors of carriers in the nanocomposite thin-film, a Zn Se QD...Photoanodic properties greatly determine the overall performance of quantum-dot-sensitized solar cells（QDSCs）. In the present report, the microdynamic behaviors of carriers in the nanocomposite thin-film, a Zn Se QD-sensitized mesoporous La-doped nano-TiO2 thin-film, as a potential candidate for photoanode, are probed via nanosecond transient photovoltaic（TPV） spectroscopy. The results confirm that the L-Cys ligand has a dual function serving as a stabilizer and molecular linker. Large quantities of interface states are located at the energy level with a photoelectric threshold of1.58 eV and a quantum well（QW） depth of 0.67 eV. This QW depth is approximately 0.14 eV deeper than the depth of QW buried in the Zn Se QDs, and a deeper QW results in a higher quantum confinement energy. A strong quantum confinement effect of the interface state may be responsible for the excellent TPV characteristics of the photoanode. For example, the peak intensity of the TPV response of the QD-sensitized thin-film lasts a long time, from 9.40 × 10^（-7） s to 2.96 × 10^（-4） s,and the end time of the PTV response of the QD-sensitized thin-film is extended by approximately an order of magnitude compared with those of the TiO2 substrate and the QDs. The TPV characteristics of the QD-sensitized thin-film change from p-type to n-type for the QDs before and after sensitizing. These properties strongly depend on the extended diffusion length of the photogenerated carries and the reduced recombination rate of photogenerated electron-hole pairs, resulting in prolonged carrier lifetime and an increased level of electron injection into the TiO2 thin-film substrate.展开更多
文摘通过使用碳纳米管(CNTs)构建三维空间导电网络,改善LiFe PO4颗粒之间的电子传导能力,研究其对LiFe PO4正极材料电化学性能的影响,并与不含CNTs的LiFe PO4正极材料进行了对比。研究结果表明,含有CNTs导电网络的电池极化程度和界面阻抗明显小于不含CNTs的电池。在0.1 C充放电倍率下,前后者首次放电比容量分别为165.6和164.4 m Ah/g,低倍率容量几乎相差不大;而在10 C充放电条件下,前者首次放电比容量达到121.9 m Ah/g,明显高于后者的109.8 m Ah/g;以1 C充电10 C放电循环1 000次,前者容量几乎无衰减,后者衰减27.8%。
基金supported by the Natural Science Foundation of Hebei Province,China(Grant Nos.E2013203296 and E2017203029)
文摘Photoanodic properties greatly determine the overall performance of quantum-dot-sensitized solar cells（QDSCs）. In the present report, the microdynamic behaviors of carriers in the nanocomposite thin-film, a Zn Se QD-sensitized mesoporous La-doped nano-TiO2 thin-film, as a potential candidate for photoanode, are probed via nanosecond transient photovoltaic（TPV） spectroscopy. The results confirm that the L-Cys ligand has a dual function serving as a stabilizer and molecular linker. Large quantities of interface states are located at the energy level with a photoelectric threshold of1.58 eV and a quantum well（QW） depth of 0.67 eV. This QW depth is approximately 0.14 eV deeper than the depth of QW buried in the Zn Se QDs, and a deeper QW results in a higher quantum confinement energy. A strong quantum confinement effect of the interface state may be responsible for the excellent TPV characteristics of the photoanode. For example, the peak intensity of the TPV response of the QD-sensitized thin-film lasts a long time, from 9.40 × 10^（-7） s to 2.96 × 10^（-4） s,and the end time of the PTV response of the QD-sensitized thin-film is extended by approximately an order of magnitude compared with those of the TiO2 substrate and the QDs. The TPV characteristics of the QD-sensitized thin-film change from p-type to n-type for the QDs before and after sensitizing. These properties strongly depend on the extended diffusion length of the photogenerated carries and the reduced recombination rate of photogenerated electron-hole pairs, resulting in prolonged carrier lifetime and an increased level of electron injection into the TiO2 thin-film substrate.
基金financial support by the National Key Research and Development Program of China (2018YFB0104300)National Natural Science Foundation of China (51772262, U20A20336, and 21935009)+6 种基金Natural Science Foundation of Hebei Province (B2020203037)Hunan Innovation Team (2018RS3091)financial support by Fok YingTong Education Foundation of China (171064)Natural Science Foundation of Hebei Province (B2018203297)financial support by the National Natural Science Foundation of China (52022088 and 51971245)Beijing Natural Science Foundation (2202046)financial support by the National Natural Science Foundation of China (51971195)。
