PbS has a see more large exciton Bohr radius of about 20 nm, which can lead to extensive quantum size effects. It has been reported that its absorption range can be tuned by adjusting the particle size of the quantum dots [16, 17]. Until now, as one of the most impressive alternative semiconductors, PbS-sensitized solar cells have been studied by many groups [18–22]. In most of the reported works, PbS quantum dots were grown on TiO2 nanotubes , ZnO nanorod arrays , and TiO2 photoanode with hierarchical pore distribution . Little work has been carried out on large-area single-crystalline TiO2 nanorod array photoanode. Compared to the polycrystal TiO2 nanostructures such as nanotubes  and nanoparticles , single-crystalline TiO2 nanorods grown directly on transparent conductive oxide electrodes provide a perfect solution by avoiding the particle-to-particle hopping that occurs in polycrystalline films, thereby increasing the photocurrent efficiency. In addition to the potential buy Gemcitabine of improving SCH 900776 order electron transport, they enhance light harvesting by
scattering the incident light. In this paper, narrow bandgap PbS nanoparticles and single-crystalline rutile TiO2 nanorod arrays were combined to produce a practical semiconductor-sensitized solar cell. Several sensitizing configurations have been studied, which include the deposition of ‘only PbS’ or ‘only CdS’ and the hybrid system PbS/CdS. Optimized PbS SILAR cycle was obtained, and the uniformly coated CdS layer can effectively minimize the chemical attack of polysulfide electrolytes on PbS layer. Therefore, the performance of sensitized solar cells was stabilized and long lasting. The power conversion efficiency of PbS/CdS co-sensitized solar cell showed an increase of approximately 500% compared with that Flucloronide sensitized by only PbS nanoparticles. Methods Growth of TiO2 nanorod arrays by hydrothermal process The TiO2 nanorod arrays were grown directly on fluorine-doped tin oxide (FTO)-coated glass using the following hydrothermal methods: 50 mL of deionized
water was mixed with 40 mL of concentrated hydrochloric acid. After stirring at ambient temperature for 5 min, 400 μL of titanium tetrachloride was added to the mixture. The mixture was injected into a stainless steel autoclave with a Teflon container cartridge. The FTO substrates were ultrasonically cleaned for 10 min in a mixed solution of deionized water, acetone, and 2-propanol with volume ratios of 1:1:1 and were placed at an angle against the Teflon container wall with the conducting side facing down. The hydrothermal synthesis was conducted at 180°C for 2 h.After synthesis, the autoclave was cooled to room temperature under flowing water, and the FTO substrates were taken out, rinsed thoroughly with deionized water, and dried in the open air.