Research On The Construction And Photoelectric Properties Of ZnO/CuInS₂and ZnO/CuInS₂/CuSCN Heterostructures

ZnO is considered as a suitable alternative to TiO2for the application innanocrystalline solar cells and photoelectrochemical cells owing to the similarenergy band structure with TiO2and high electron transfer rate （200cm²/v·s）. In thispaper, CuInS₂and β-CuSCN was taken as shell material respectively to synthesizeZnO-based core/shell constructure, and the photoelectric properties of ZnO/CuInS₂and ZnO/CuInS₂/CuSCN heterostructures were studied.1. Due to the large differences in solubility product constant of ZnO, ZnS andCuS, ZnO nanorods could be converted to ZnO/ZnS and ZnO/CuS intermediarytemplates via an intermediary conversion route based on the ion-by-ion growthmechanism. The conversion of intermediary template to target product, ZnO/CuInS₂core/shell nanorods array, is considered to result from a polyol reduction process.CuInS₂shell with a thickness of5²0nm could be obtained by fixing the water bathtime of ZnO nanorods in thioacetamide solution at5h,7h and9h whensynthesizing the intermediary for ZnO/CuInS₂core/shell nanorods array.2. Owing to the chemical stability of CuInS₂shell and gradient energy gapstructure formed with the constructed core/shell heterostructure, the stability ofcorresponding photoelectrode against photoetch was improved, and an absorb centerlocated at about570nm could be observed. The application of as-obtainedZnO/CuInS₂heterostructure in dye sensitized solar cells solar cells was studiedusing N3dye as sensitizer, and the efficiency of as-fabricated cell was1.36%.Compared with single-sensitized by N3dye, the solar cell employing CuInS₂/N3co-sensitized system exhibited an improved efficiency by about24.8%.3. The photocurrent density obtained using ZnO/CuInS₂core/shell nanoarray aselectrode was improved by99%, compared with that of ZnO nanorods, indicatingtypical property of photoelectrochemical cell. When the water bath time was7h, thehightest photocurrent density （16.9mA/cm²） was obtained using as-obtainedZnO/CuInS₂core/shell nanoarray as electrode, and the corresponding hydrogengeneration efficiency was3.2%.4. Considering the effects of the deposition parameters, CuSCN was deposited into ZnO/CuInS₂core/shell heterostructure nanorods array to constructZnO/CuInS₂/CuSCN heterostructure. The results showed that ZnO/CuInS₂/CuSCNheterostructure with good morphology would be obtained when the depositiontemperature was30°C, the deposition potential was-500mV, the deposition timewas2400s, and [Cu²⁺]:[SCN-]=1:5. In addition, the constructed heterostructurecould absorb part of the visible light, with an absorb center located at about550nm.Furthermore, under the simulated sunlight （100mW·cm-2）, an open-circuitphotovoltage of324mV and a short-circuit photocurrent of1.22mA/cm²wasobtained respectively with the fabricated extremely thin absorber solar cells,indicating an efficiency of0.16%.