With the advent of the knowledge-based economy, the creation and diffusion of technological knowledge is considered the principal determinant of competitiveness. Recently, with widespread recognition that the creation and diffusion of technological knowledge causes inter-industrial innovations and provides new sources of growth, it has been accepted as a critical factor in determining a firm’s competitiveness as well as a country’s economic growth. Based on this background, this dissertation analyzes technological knowledge flows and technological collaboration relationships among innovators using network theory. This dissertation consists of three independent essays. The goal of first essay is to understand the structure and characteristics of technological knowledge flows between countries, institutions, and technology fields in the field of organic photovoltaic cells (OPCs). This essay was conducted in three stages: data collection, network creation, and network analysis. For network analysis, network visualization, network topological analysis, and node centrality analysis were performed in sequence. The network topological analysis revealed that all three citation networks, i.e., countries, institutions, and technology fields, are scale-free networks that follow the power law and display, to a greater or lesser extent, a more efficient knowledge transfer capability than a random network of the same size. The node centrality analysis showed that the United States, Japan, and Germany are the most important citation centers in the country citation network, while Boeing, Konarka Technologies, Eastman Kodak, and Sharp are the most important in the institution citation network, and the U.S. patent classification (USPC) classes of 136, 257, and 428 are the most important in the technology field citation network, each playing critical roles in each the network as core nodes. In this essay, I applied various concepts of centrality to the analysis of individual nod...