View metadata, citation and similar papers at core.ac.uk brought to you by CORE QUARTERLY REVIEW No.20 / July 2006 4 Trends in Materials Informatics in Research on Inorganic Materials TOYOHIRO CHIKYOW Affiliated Fellow organic materials informatics than by inorganic 1 Introduction materials informatics. Automatic analyzers have been developed for bioinformatics, and Informatics is a science in which a new large-scale data processing is carried out for knowledge system is built up by collecting and the analysis of gene sequence data. These classifying information using computers and data are then used for the construction of networks. Materials informatics is a technique gene information databases and statistical that aims at innovative materials development by analysis. Personalized medicine is one of the way of informatics, which includes such elements accomplishments of this sort of bioinformatics as materials design using computation science analysis. In the fields of organic materials and and databases, preparation of experimental polymer development, new materials are also design schedules for materials synthesis, being developed by means of systematic synthetic automatic combinatorial synthesis when methods using combinatorial methods and data searching for new materials, high throughput processing technologies to cope with the large screening, compiling databases from obtained amounts of data involved. data, data sharing through networks, visualization Although informatics has not yet been widely of data, and data mining to predict future used for inorganic materials, such as ceramics, materials. Materials informatics requires the glass, and semiconductors, some organizations integration of all these elements [1]. are now conducting research and development In the application of informatics, more progress into the use of informatics for synthetic has already been made by bioinformatics and processes, developing new catalysts by means Figure 1 : Relationship between the development of various materials and informatics 59 SCIENCE & TECHNOLOGY TRENDS QUARTERLY REVIEW No.20 / July 2006 of combinatorial materials and integrating library of compounds with similar molecular various processes from materials design through structures, and the activities of specific chemical to collection of the data in a single data set. structures and their reactions with functional Particularly in the research being carried out by groups can then be predicted utilizing such a commercial companies, systematic searches for library. When possible candidate combinations new materials are now being made which require for a specific purpose are found, such large-scale data analysis, resulting in the need for combinations are selected and commercialized. materials informatics in this field also [2]. The process is being automated further using robots, and many venture companies have been established in this field. However, since the 2 Similarities to and purpose of informatics is to monopolize the Differences from Informatics results ahead of other companies, these databases in Other Fields are often kept within the confines of a company Similarities and differences with inorganic or group. materials informatics can be clarified by Also in the field of inorganic materials comparison with other existing fields in research, much data on ceramics, glass and informatics. As mentioned above, informatics has semiconductors have been accumulated with already been used in the fields of bioinformatics regard to their material characteristics, crystal and organic synthesis. structures, and suchlike. However, past data in The bioinformatics system has been established this field have often been collected by different by integrating gene information and genetic research groups and stored in different forms, statistics [4], and research on bioinformatics is some numerical and some graphical, and not all being actively pursued. Bioinformatics aims at of these are compatible with each other. Another organizing the genetic information of organisms difficulty in applying informatics to research (the genome) and consists of database-related on inorganic materials results from the fact functions such as the systematic collection that a material can have diversified aspects and and storage of data on DNA base sequences, properties that cannot always be simply defined and data analysis software that visualizes the digitally. Research on inorganic materials is data so that they can be intuitively compared. quite different from that on organic materials or Bioinformatics analyzers create these large-scale biology where digital expressions can be used. databases automatically, using the most advanced For example, while zirconium dioxide (ZrO2) is computer technologies available to process large used as a material for gate insulating film, it is amounts of data rapidly. Since there is a problem also used as an ion conductor. When zirconium of compatibility between the data obtained by dioxide is used as a material for gate insulating different research organizations, tools are used film, it is necessary to reduce the number of to transform the data so that they can be shared oxygen-induced holes so that the insulating among these organizations. characteristics are improved. In this field, Organic synthesis is another field in therefore, most of the data accumulated refer to which informatics is being developed. Since the addition of agents to improve the insulating combinatorial methods, by which a large characteristics and the values of the insulating group of compounds can be synthesized at characteristics obtained. In contrast, when one time by combination, greatly increase zirconium dioxide is used as an ion conductor the speed of materials synthesis and make or sensor to increase conductivity by increasing it possible to pioneer the creation of new the oxygen-induced hole concentration, most of materials, this technique has been widely used the data collected apply to processing conditions for the development of new polymers and that reduce electrical resistance and impurities pharmaceuticals. The use of combinatorial that increase conductivity. In this way, completely synthesis makes it possible to create a large-scale different data are required for the same material, 60 61 SCIENCE & TECHNOLOGY TRENDS QUARTERLY REVIEW No.20 / July 2006 depending on the purpose of the research. systems are aiming at different targets, so the Therefore, a materials informatics system cannot results are not always organized in a mutually be built by conventional methods in which compatible form. Since materials informatics is different materials are synthesized by different still only in the initial stages of development, it is methods and only specific characteristics are necessary to share databases in order to mutually evaluated. complement the database information already The use of the combinatorial materials available. Evaluation items in materials research synthesis method in the development of inorganic are so diversified that it is difficult, in practice, materials can change all this [3]. It has been to automatically measure all the data involved, shown that the use of combinatorial method so it is in everyone’s benefit that all research to synthesize a large group of compounds by organizations assist each other by sharing data. combination is a very effective way to develop new materials such as catalysts. Building an 3 Present Status of Materials informatics system requires that the relevant Informatics and Issues characteristics are measured automatically to be Addressed and systematically at each stage and that the data are then stored. Therefore, in addition Research activities in inorganic materials to “Combinatorial Materials Synthesis”, the informatics are being conducted separately establishment of “High Throughput Screening” by each research group in each country, and is indispensable when building a materials this limits their achievements considerably. informatics system. Activities are still focused at the discussion When developing an informatics system, stage concerning the control and storage of experiments must be carried out by combining data relating to combinatorial experiments and the combinatorial materials synthesis method, have not yet reached the stage of data mining in which enables systematic changes to be made which searches are carried out for new materials. in composition and growth conditions, with the This results from the fact that different research evaluation of the characteristics of synthesized groups collect data using different methods materials. In the example of zirconium dioxide, so that data cannot always be shared. As a mentioned above, characteristics such as oxygen consequence, data suitable for data mining have partial pressure and electrical resistance are therefore not yet been collected. In addition, automatically measured and these data are stored characteristics evaluation takes considerable time, in a single data set along with the synthetic making it difficult to collect much data in a short conditions. Some data from this data set can then period. Thus, it will take a long time to achieve be used to provide information on insulation the materials informatics goal of being able to films for dielectric gates while other data can be predict new materials by means of data mining. used to provide information on ion conductors. However, research towards this materials The collection and compilation of such a data informatics