The Preparation And Performance Study Of CIGS Films And Prototype Cells

Copper indium gallium selenide(Cu(In,Ga)Se₂,abbreviated GIGS) thin film solar cells for its high conversion efficiency,low cost,stable performance,etc.,while having caused wide concern by the international photovoltaic industry.In order to establish the foundation for arge-scale commercial applications of CIGS solar cells, mainly from high-performance,low-cost and environmentally friendly,such as the point of view,the vacuum and non-vacuum preparation technologies of the absorption layer and buffer layer have been researched.Therefore,the thesis structure is also divided into three main parts,as follows:The first part mainly includes the exploring the preparation technology of high-performance CIS/CIGS thin-film solar cells by vacuum sputtering and selenization process,and study the reaction mechanism.First,the CIS thin films are prepared by RF sputtering and selenium.The CuIn metal layers are prepared by sputtering the Cu target and In target.In order to replace the highly toxic H₂Se,the selenium powder is used to selenide the CuIn metal layers.Nearly stoichiometric copper-rich CIS thin films are obtained.The film structure,morphology and electrical properties are characterized.The best selenide temperature 500℃is obtained,and inferred the reaction route of CIS is generated by the CuSe and InSe compound at a high temperature.Then CIGS thin films and devices are prepared by RF sputtering and selenium.In order to obtain the gradient bandgap "sandwich" structure of high performance cells,CuInGa metal layers are parpared through alternating sputtering CuInGa alloy target and In target.Taking advantage of multi-step hierarchical method of selenization,it reduces the process of segregation Ga.And the high-quality CIGS thin films are obtained,and the photoelectric conversion efficiency of CIGS thin-film devices is 4.67%.Finally,the CIS thin films are prepared by the pulsed laser deposition(PLD) and selenization.It uses the high vacuum of PLD chamber for the low-temperature alloy of the metal pre-layers.After selenization,the stoichiometry of the CIS thin films are obtained,absorption coefficient reaches a 10⁵ cm^-1 order of magnitude,optical band gap is 0.98 eV,which is the proof of low-temperature alloying process in favor of CIS single-phase formation.The second part is the CIS thin films prepared by low-cost non-vacuum methods. First of all,the use of simple electro-deposition preparation of CIS thin film technology.In this experiment conductive glass(ITO) is use as the substrates.Using potentiostatic deposition method are successfully prepared in line with the stoichiometry of the CIS thin films,and visited the deposition potential,solution PH value,the concentration ratio,as well as complex annealing process and other factors and concluded that the best technology of electrodeposition CIS thin film:ratio of Cu: In:Se=1:5:2,the concentration of complexing agent for sodium citrate 0.1M/L,in PH value of 1.7,voltage of 1.6V under the conditions of preparation of CIS thin film is better,the crystallization properties of annealed films increases.Secondly,the low cost non-vacuum spin-coating process is used to prepare the CIS thin-film devices. Respectively,Cu-In and Cu-In-Se two soluble salt as precursor,using a simple easy-to-use spin-coating of the CIS thin film,explored a single-phase nature of the better CIS thin films prepared by spin-coating of non-vacuum process,and to study different precursors of the film into a slurry with the quality and performance of law, results indicate that it can obtain better smooth thin-film used the Cu-In-Se precursors. Using non-vacuum method,solar cells devices efficiency obtains 0.97%.The last part is the preparation for the environment-friendly non-toxic buffer layer material ZnS Thin Films.First of all,the wet chemical bath and electro-deposition process are used to prepare ZnS thin film,and we explore the best technology of preparation ZnS thin film by electrodeposition and chemical bath routes: PH=3,U=0.1V,t=30min;T=80℃,t=15min,investigated the effects of annealing process,and through a variety of characterization by means of two processes are compared,and we conclude that the electrochemical method obviously superior to the traditional CBD method.Secondly,mainly want to develop the whole dry process of CIGS manufacturing.At different deposition temperatures the high-quality ZnS thin films are prepared,and films are characterized.Compareing to wet deposition technology of CdS films,it has many advantages,such as low cost, non-toxic environmental protection and more short-band optical absorption edge.It is expected to be applied in the whole dry process of manufacturing CIGS thin film cells.