Direct Nanocoupling between Sulfide- and Oxide-Semiconductors by a Photodeposition Technique

利用TiO_2的光致性、光催化性和表面超亲水性，开发了一种简单而通用的光沉积技术，用于金属硫化物量子点与TiO_2的非尺度耦合。金属硫化物- tio_2耦合体系具有以下特点：(1)在较短的时间内可在TiO_2上直接形成大量的金属硫化物，且具有良好的重现性；(2)金属硫化物量子点的能带能可通过辐照时间或表面改性剂浓度广泛调节；(3)金属硫化物量子点不仅可以沉积在介孔TiO_2纳米晶膜的外表面，而且可以沉积在介孔TiO_2纳米晶膜的内表面，而不会堵塞孔。（四）简单的低温溶液技术使生产成本低，（五）该技术具有广泛的可能性，可以将TiO_2与适合应用于太阳能转换的窄间隙金属硫化物偶联。这些独特的特性使所得到的异杂阳极作用体系具有优异的光催化剂性能和用于水制氢的QD-SSC和QD-SPEC电池的光阳极性能。

Simple and versatile photodeposition techniques taking advantage of the photoinduced properties of TiO_2, photocatalysis and surface superhydrophilicity, have been developed for coupling metal sulfide QDs and TiO_2 at a nonoscale. The coupled metal sulfide-TiO_2 systems possess the following characteristics : (I) a large amount of metal sulfides can be directly formed on TiO_2 during a fairly short period with excellent reproducibility, (II) the band energies of metal sulfides QDs are widely tunable by irradiation time or surface modifier concentration, (III) metal sulfide QDs can be deposited on not only the external surfaces but also the inner ones of mesoporous TiO_2 nanocrystalline films without pore-blocking, (IV) the simple solution-based technique at low temperature enables the low-cost production, (V) this technique has a wide possibility for coupling TiO_2 and narrow gap metal sulfides suitable for the applications to the solar energy conversion. These unique features produce the excellent performances of the resulting heteronanojunaction systems as photocatalysts and the photoanodes for QD-SSC and QD-SPEC cells for hydrogen production from water.