Chuang Han,Zhang Chen,Nan Zhang,Juan Carlos Colmenares,Yi-Jun Xu
A simple, low-temperature synthesis approach is reported for planting CdS-sensitized 1D ZnO nanorod arrays on the 2D graphene (GR) sheet to obtain the ternary hierarchical nanostructures, during which graphene oxide (GO) as the precursor of GR acts as a flexible substrate for the formation of ZnO nanorod arrays. The hierarchical CdS-1D ZnO-2D GR hybrids can serve as an efficient visible-light-driven photocatalyst for selective organic transformations. The fast electron transport of 1D ZnO nanorods, the well-known electronic conductivity of 2D GR, the intense visible-light absorption of CdS, the unique hierarchical structure, and the matched energy levels of CdS, ZnO and GR efficiently boost the photogenerated charge carriers separation and transfer across the interfacial domain of hierarchical CdS-1D ZnO-2D GR hybrids under visible light irradiation via three-level electron transfer process. Furthermore, the superior reusability of ternary hybrids is achieved by controlling the reaction parameters, i.e., using visible light irradiation and holes scavenger to prevent ZnO and CdS from photocorrosion. This work demonstrates a facile way of fabricating hierarchical CdS-1D ZnO-2D GR hybrids in a controlled manner and highlights a promising scope of adopting integrative photosensitization and co-catalyst strategy to design more efficient semiconductor-based composite photocatalysts toward solar energy capture and conversion.
In this paper, novel chestnut-like TiO 2 was successfully synthesized by the hydrothermal method. The presence of chestnut-like structure not only increased the density of active sites with a high accessibility, but also facilitated the diffusion of solvent and products. Then, the chestnut-like TiO 2 based thin films on FTO were successfully prepared by the doctor-blade method. Moreover, the thickness of thin films can be adjusted via different repeated times. After that, in order to further improve its photoelectric properties, the adoption of CdS sensitization with different time interval via chemical bath route was studied. Photoelectrochemical (PEC) measurements showed that CdS/TiO 2 photoelectrode under the optimal condition exhibited minimal resistance and the fastest charge transfer rate. The highest photocurrent density can reach 35.1 μ A ⋅ cm − 2 , which is almost 5-fold than that of pure chestnut-like TiO 2 (7.6 μ A ⋅ cm − 2 ) based thin films. The enhanced PEC properties could be ascribed to the improvement of light harvesting and the formation of heterostructure to accelerate the separation of photo-generated electron-hole pairs.
High performance CdS sensitized TiO 2 nanorod arrays based solar cells are fabricated by polymer-assisted layer-by-layer adsorption and reaction (PA-LBLAR) method. The PA-LBLAR method can well control the deposited size of CdS on the TiO 2 nanorod arrays, which are grown on Ti foils by hydrothermal route then transferred to transparent conductive glasses. The UV–vis absorption spectra show that with the increasing deposition times, the absorption spectra of photoelectrodes increased to a broader wavelength range, which is originated by the better coverage and increased size of CdS quantum dots on the TiO 2 nanorod arrays as detected by SEM and TEM images. The highest power conversion efficiency of the cells (AM 1.5 G, 100 mWcm −2 ) up to 2.944% can be obtained with 7 cycles of PA-LBLAR deposition of CdS sensitized layers in the photoelectrodes, which is much higher than that of the best performance of cell with 14 cycles of traditional successive ionic layer adsorption and reaction processes.
Sun Yunfei,Yang Lili,Wei Maobin,Chen Gang,Che Guangbo,Yang Jinghai,Wang Zhe,Gao Zhiyuan
Well aligned CoS NRAs with different length have been grown on ITO substrates by a simple chemical method without any catalyst. The morphology properties of the as grown CoS nanostructures were investigated by SEM and TEM images. From the SEM results measured from the tilt-view, with the reaction time increasing, the length of CoS nanorods increased. However these CoS(6) NRAs partially aggregated, which will decrease the surface area of CoS NRAs. The optimized photovoltaic performance with a Voc of 0.66 V, a Jsc of 1.96 mA/cm 2 , an FF of 0.43, and a η of 0.64 % is obtained from the device based on CoS(4) ANRAs electrode. Although the quantum dot sensitized solar cells (QDSSCs) with CoS NRAs show smaller η values than that of the QDSSC with sputtered Pt counter electrode, the CoS material will be an efficient alternative for the Pt electrode due to its excellent catalytic ability and low cost.
危险品化学品经营许可证（带存储）