Mapping countries cooperation networks in photovoltaic technology development based on patent analysis

Research activities on solar energy has been growing and use of patents becomes an important innovation source for many types of studies. This paper aims to analyze solar photovoltaic (PV) patents and describes its assignees cooperation profile. PV patents based on IPC Green Inventory code were selected from 1990 to 2014, filtered out co-ownership patents and use social network analysis (SNA) to find PV technology development networks. Main findings are an increase of patents assignees over the years and a general concern for develop technologies “Devices adapted for the conversion radiation energy into electrical energy”, “Assemblies of a plurality of solar cells” and “Silicon; single-crystal growth”. SNA enabled to identify four countries clusters that presented cooperation behavior and shared similar concerns in PV technology development. The USA, China, Spain and Korea were main countries of each cluster. Furthermore, through network statistics, it implied that a country that had more patents was not the most important on that technology development. The USA, Germany and UK were the most relevant countries in PV technologies because they were the ones with more cooperation with other countries and with the most collaborative countries overall. Thus, these countries are the largest holders and influencers in PV technologies development. Based on the structure and interaction between country clusters, it is possible to understand who cooperates or competes with whom. So, this information allows establishing strategies of partnerships, or even of competition, between countries, firms and research centers.