Invisible transistors for transparent electronics
Transparent devices rely on essentially invisible electronic and optoelectronic circuits. In order to have invisible circuitry, one must have optically transparent thin-film transistors (TFTs). Conventional semiconductor materials and technology are not easily adapted to such applications. Traditional organic semiconductors usually absorb light in the visible range of the electromagnetic spectrum, making them visible to the naked eye. In addition, their performance is inhibited when processed from a solution as is necessary to produce low-cost electronics. European scientists set out to develop new materials and their processing methods for fabrication of transparent electronics and displays with EU funding of the Organic Electronics project. To date, scientists have developed new materials tested in organic thin-film transistor (OTFT) architectures. Theoretical (density-functional-theory, DFT) calculations have greatly enhanced experimental results. Researchers have achieved organic semi-conducting structures including nanowires and carbon nanotubes (CNTs), and tested the most promising materials in TFT structures. The structures demonstrate electrical performance (charge carrier mobility) competitive with that of state-of-the-art materials, among the highest of those reported in the literature. Continued work promises to push the frontiers of flexible, transparent electronics with optimisation of materials and processing technology for superior-performance, transparent TFTs.
