High-Throughput Experimentation On Doping Effects Of VIA Group Compounds For Energy Applications

Traditional materials research based on"trial and error"method is inefficient and cannot meet the urgent need for new materials in today's scientific research and technology development.Material Genome Engineering is the forefront of the current development of materials science,aiming to improve the efficiency of materials research by combining material calculations,high-throughput experiments,and database technologies.The high-throughput experimental technique is the basis of Material GenomeEngineering,includinghigh-throughputmaterialpreparationand high-throughputmaterialcharacterization.Thehigh-throughputexperimental technology can significantly shorten the material development cycle by increasing the throughput of experimental samples per unit time.At present,the high-throughput characterization technology has been developed relatively well.The optical-based detection methods have enabled the characterization of materials on the micro-nano scale,while methods based on non-contact probes have achieved submicron-level characterization.However,the high-throughput material preparation techniques still need to be improved in terms of experimental throughput,preparation speed,and range of preparation techniques.For example,high-throughput combinatorial material chip technology,the more mature one of the high-throughput material preparation techniques,still has some limitations in the preparation of combinatorial material samples,which seriously limits the further improvement of the efficiency of material experiments.The reasons for this limitation could be mainly attributed to:the shadowing effect of the physical mask,poor control stability and uniformity in multi-physics fields,and the compositional error of the traditional combinatorial material preparation method.With the growing crisis of fossil energy,the development of energy materials for energy generation and energy storage technologies has become an important development direction in the field of energy technology.Among the energy materials,there are many VIA-group compounds,represented by oxides,sulfides,and selenides.Therefore,research and development of VIA-group compound energy materials with excellent performance have become a hot topic of research.Currently,high-throughput experiments methods have been successfully applied to the experimental screening of most oxide materials,partially stabilized sulfides and selenide materials.However,some of the VIA-based compound materials,which are sensitive to water and oxygen or have poor thermal stability,such as Li₂S-GeS₂-P₂S₅?LGPS?pseudo-ternary sulfide solid electrolyte and some rare earth oxide material,have rarely been reported due to their harsh requirements for preparation process.This paper proposes a comprehensive solution to meet the need of high-throughput research of energy materials based on Group VIA compounds.First,a wet chemical-based high-throughput combinatorial chemical bath deposition technique,a high-throughput ion beam sputtering technique,an e-beam evaporation technique and an in-line high-throughput magnetron sputtering technique were developed.Next,a high-throughput experimental study of Sb-doped CuIn_0.6Ga_0.4Se₂?CIGS?thin films and a Ge-doped LiPS thin film were performed by combining those preparation techniques with high-throughput characterization methods,such as scanning X-ray diffraction and local electrochemical impedance spectroscopy?LEIS?.Then,cluster analysis was used to systematically analyze the obtained data.The above selected examples of VIA group compound material have the characteristics of poor thermal stability and sensitivity to water and oxygen respectively.The above techniques can also be used for high-throughput experimental studies of the common oxide material systems.This paper includes the following aspects:1.Developed four new high-throughput combinatorial material chip preparation techniques for different applications.In order to solve the bottleneck problems of the high-throughput combinatory material chip preparation technique,an in-line multi-target magnetron sputtering process,an optimized relative position of the target and the substrate for the ion beam sputtering,an improved real-time solution ion concentration feedback&control mechanism,and an adjusted relative position of the multi-crucibles module and the substrate for the e-beam evaporation was introduced,which resulting in preparation of large-area uniform thin films?percentage of non-uniform thickness is less than 3%?by magnetron sputtering,ion beam sputtering,chemical bath deposition,and e-beam evaporation respectively.On the other hand,stable distribution of physical fields in magnetron sputtering,ion beam sputtering,chemical bath deposition,and e-beam evaporation was ensured by optimizing the magnetization fields of the targets,temperature field of the water bath process,ion beam spot shape,and electron beam electromagnetic field.Moreover,controllable composition distribution in magnetron sputtering,ion beam sputtering,e-beam evaporation,and chemical bath deposition was realized through the development of continuous/discrete mask automatic change devices,continuous mask control mechanisms,mask moving and substrate rotation module,and automatic substrate lifting and rotation control mechanisms.Integrating the above technologies,the high-throughput combinatorial material preparation technologies based on magnetron sputtering,ion beam sputtering,e-beam evaporation and chemical water bath deposition were developed respectively.The above techniques can realize the preparation of the100-step continuous phase diagram combinatorial material chips,the 64×64 discrete sample combinatorial material chips,the combinatorial material chips with minimum step size 25?m and the samples with a step length of more than 1 cm.In addition,considering the diffusion-crystallization competitive process determined by the critical thickness during the heat treatment of multi-layer films,and the requirement of the high accuracy data for material calculations model,a gradient superlattice based combinatorial material preparation method was developed.2.Taking advantage of the high-throughput material experiments,the influence of Sb doping on the grain growth kinetics of CIGS thin film was investigated.By comparing the samples with various preparation conditions,including with or without Sb doping,different temperatures in heat treatment,and different Sb₂S₃ preparation sequences,the phase,microstructure and composition of Sb-doped CIGS absorber films was studied systematically.The paper verifies the phenomenon discovered by Mitzi et al,the Sb doping lowers the crystallization temperature of the CIGS absorber layer film,and presents the evidence that the size of the CIGS crystal grains becomes obviously larger below 450°C?below the CIGS melting temperature?.To further explore the mechanism of Sb doping promoting the growth of CIGS crystal grains,we prepared CIGS thin film samples with various Sb contents using self-developed high-throughput combinatorial chemical bath deposition technique.Combined with both regular characterization methods?such as XRD,XPS,EDS,and SEM?and high-throughput characterization methods?such as LEIS?,the influence of various content of Sb doping on the grain growth of CIGS was systematically studied.Based on the above results,a Sb₂Se₃ quasi-liquid phase promoted CIGS film-growth model was put forward.3.The phase and impedance distributions of Li₂S-GeS₂-P₂S₅ pseudo-ternary sulfide material systems were presented based on the high-throughput combinatorial experiment.By designing a sandwich-based electrochemical test chip,the Li₂S-GeS₂-P₂S₅ pseudo-ternary system can be testing and prolonged exposure in the atmosphere and aqueous environment.With the above high-throughput e-beam evaporation combinatorial material chip preparation system and the design of the electrochemical test chip,the Li₂S-GeS₂-P₂S₅ combinatorial material chips was prepared.Combining high-throughput characterization techniques as well as cluster analysis make it possible to study on the phase and impedance distributions of Li₂S-GeS₂-P₂S₅pseudo-ternary system.