Identify technology main paths by adding missing citations using bibliographic coupling and co-citation methods in photovoltaics

The objective of this research is to study the technology main paths by adding missing citations through the use of bibliographic coupling (BC) and co-citation (CC). Core patents are identified and used for patent citation network (PCN) analysis. In the citation network, patents with strong links are analyzed to construct the technology main paths. Previous researches have shown that both bibliographic coupling and co-citation may help in finding missing citation patents, so this study will utilize bibliographic coupling and co-citation to add missing citations into the original citation network and construct the technology main paths in the field of photovoltaic by connecting the strong links. The time duration of main paths from the original photovoltaic patent network has been relatively short. Furthermore, the number of patents has not exceeded three. A possible reason to explain the short time duration may be the nature of patents that is focused on technological innovation. On the contrary, the photovoltaic network after adding the missing citations has contained more links and presented a more complete trail for the main paths. Moreover, the network has sustained for longer in time duration. The results indicate that utilizing BC and CC methods to supply missing citations is an effective way in constructing the technology main paths.