Organic light emitting diodes (OLEDs) based on multi-layer OLED structures were started in the middle of 80th. Organic materials and devices are a prime focus of OLED research. The successful OLED technology has already been put to practical use in car-monitor, mobile phone display and organic TV. Now, OLED developments aiming for high efficiency and long lifetime have been extensively studied both in academia and industry in the worldwide.
The active matrix OLED displays require thin-film transistors. In order to realize practical use of flexible displays, organic field-effect transistors (OFETs) are getting attentions since they can be fabricated on plastic at low temperature. We research for light emitting organic field-effect transistors, ambipolar organic field-effect transistors, and design new materials and device structures.
Organic light emitting diodes (OLEDs) have been extensively developed during the past 15 years and various commercial applications have recently been introduced by utilizing the unique characteristics of organic materials, such as high photoluminescence (PL) quantum efficiency, a tunable emission spectrum in visible regions, and electrical conduction in a high electrical field. Over recent years, a wide variety of challenges aiming for electrical pumping of organic laser diodes have been addressed. However, organic laser diodes have still not been realized owing to their high lasing threshold under electrical pumping. To realize organic semiconductor laser, injecting and transporting high current density over few KA/cm2 and suppressing exciton annihilation under high current density are required.
Now, we need concrete actions to solve environment and energy problems, and the importance of photovoltaic generation has been increasing. Because organic thin-film solar cells can be fabricated by low-temperature process, the cost for fabrication is less than that for conventional silicon solar cell. Furthermore, because they are light weight and flexible, there is a possibility that they will be used as general power-generation devices.