Research On The ZnO/Metal Sulfide Core/Shell Nanoarrays And Photovoltaic Properties

As quantum dots sensitized organic-inorganic solid-state solar cell possesses the advantages of both quantum dots sensitized solar cell and solid-state solar cell, it has been becoming a kind of promising solar cell. One dimensional Zn O nanoarrays film is widely used as the photoanode of solar cell due to its high specific surface area, easy preparation into various nanostructures and high electrons transmission rate. In this paper, highly ordered one-dimensional Zn O nanoarrays film on ITO substrates was used as photoanode in the quantum dots sensitized solar cell. The photoelectric performance of solar cell can be optimized by choosing binary or ternary metal sulfide as sensitizers, which have the appropriate energy level structure and high light absorption efficiency. The composite structures can broaden the light response region, enhance the light absorption efficiency and promote the separation, injection and transmission of electrons.The preparation process of binary metal sulfide sensitizers(such as Sb2S3, Ag2 S, Cu S, Cu2 S, Cd S, Bi2S3)modified Zn O nanoarrays was mainly through the chemical conversion method based on ion-exchange, or on the basis of combination of this method and solvothermal method or heat treatment method for preparation of ternary metal sulfide sensitizers(such as Ag In S2, Zn In2S4, Ag3 Cu S2 and Ag Sb S2 modified Zn O nanoarrays. During the preparation processes, these reaction conditions are facile, easy to control, no strict demend for equipment. A quantum dots shell of binary or ternary sensitizers around the nanoarrays surface was formed on the Zn O nanoarrays surface. This method can also be used as a versatile preparation technology to synthesize other binary or ternary sensitizers based on Zn O nanoarrays.In this paper, the Zn O/Zn S/Sb2S3 nanoarrays, Zn O/Zn S/Ag In S2 nanoarrays and Zn O/Ag3 Cu S2 nanoarrays with appropriate morphology and structures were prepared successfully by the combination of chemical conversion and solvothermal method or heat treatment method. The power conversion efficiencies of these above quantum dots sensitized organic-inorganic solid-state solar cells are 1.32%, 2.11% and 2.01%, respectively. These binary or ternary metal sulfides based on preparation of chemical conversion method with appropriate morphology and structure as sensitizers have the following advantages:(i) a higher efficiency of light-harvesting in the visible region;(ii) photosensitizers on the surface can enhance the light utilization efficiency;(iii) appropriate matching of the energy band structures;(iv) highly ordered nanoarrays offer direct electrical pathways for photogenerated electrons, leading to a higher electron transport rate. Therefore, binary or ternary metal sulfide modified Zn O nanoarrays was prepared by chemical conversion method, which implies a promising structure for application in all-solid-state solar cell.