Cu2S film onto FTO glass substrate was obtained to function as counter electrode for polysulfide redox reactions in CdS/CdSe co-sensitized solar cells by sintering after spraying a metal chalcogenide complex, N4H9Cu7S4 solution. Relative to Pt counter electrode, the Cu2S counter electrode provides greater electrocatalytic activity and lower charge transfer resistance. The prepared Cu2S counter electrode represented nanoflower-like porous film which was composed of Cu2S nanosheets on FTO and had a higher surface area and lower sheet resistance than that of sulfided brass Cu2S counter electrode. An energy conversion efficiency of 3.62% was achieved using the metal chalcogenide complex-mediated fabricated Cu2S counter electrode for CdS/CdSe co-sensitized solar cells under 1 sun, AM 1.5 illumination.
Semiconductor sensitized solar cells(SSSCs) are promising candidates for the third generation of cost-effective photovoltaic solar cells and it is important to develop a group of robust, environment-friendly and visible-light-responsive semiconductor sensitizers. In this paper, we first synthesized bismuth vanadate(Bi VO4) quantum dots by employing facile successive ionic layer adsorption and reaction(SILAR) deposition technique, which we then used as a sensitizer for solar energy conversion. The preliminary optimised oxide SSSC showed an efficiency of 0.36%, nearly 2 orders of magnitude enhancement compared with bare Ti O2, due to the narrow bandgap absorption of Bi VO4 quantum dots and intimate contact with the oxide substrate. This result not only demonstrates a simple method to prepare Bi VO4 quantum dots based solar cells, but also provides important insights into the low bandgap oxide SSSCs.
Yi LiJun ZhuHui ChuJunfeng WeiFeng LiuMei LvJunwang TangBing ZhangJianxi YaoZhipeng HuoLinhua HuSongyuan Dai
The mechanism of the conversion of titanate nanotubes into nanoribbons is of considerable interest.The details of the transformation processes involved when nanoribbons are produced from a P25 TiO 2 powder precursor by alkaline hydrothermal treatment have been investigated systematically by transmission electron microscopy.A multistep attachment model is proposed for the growth at the early stage of coarsening.The treatment duration has a strong effect on the change in product morphology from hollow nanotubes into nanoribbons,since the nanotubes cannot retain their morphology in the strong alkaline solution for extended periods of time.Most of the nanotubes were etched and dissolved,providing the nutrients for subsequent nanoribbon growth.Some stable nanotubes grew spirally internally to form nanowires or became connected together to form rafts which acted as the grains for nanoribbon growth.With increasing hydrothermal time,a large number of nanotubes and other fragments became attached to the grains which began to grow larger and eventually formed the nanoribbons,in a process in which the stepped faces and kinked faces became fused and were eliminated while the flat faces were retained in the nanoribbon morphology.
