Abstract
Organic light-emitting diodes (OLEDs) possess many advantages, such as large viewing angle, low power consumption, processing feasibility, short response time, higher brightness and flexibility. It is therefore promising for applications in the newly booming market of next-generation flat panel display. For future display applications, large information capacity, high resolution and lower power consumption are required. As consequences, active-matrix organic light-emitting diodes (AMOLEDs) will be the main stream in FPD market. In this thesis, the integration of driving organic thin-film transistor (OTFT) and OLED, employing identical polymeric semiconductor as active layer, on the same glass substrate was tested. We use MEH-PPV as the material of the emitting layer of OLED and the active layer of organic thin-film transistor. For the fabrication of OLED, ITO film was patterned on the glass substrate as the anode electrode. PEDOT as hole transport layer and MEH-PPV as emitting layer were then spin-coated on ITO film in turn. Finally, Ca/Al as the cathode electrode was evaporated on the light-emitting layer. For the construction of OTFT, the ITO patterned film was used as Gate electrode. SiO2 films of 300 nm was deposited on ITO by APCVD or PECVD. Gold electrodes for use as Source and Drain were then defined by photolithography. Finally, MEH-PPV as the material of active layer was spin-coated on the region between Source and Drain. With our OTFT operating in the accumulation mode, high field-effect mobilities of 3×10-4cm2/V-s with a threshold voltage VT=2V in saturation regime and 10-3cm2/V-s with VT=3V in linear regime were demonstrated. In addition, our OLEDs based on MEH-PPV exhibit good electrical characteristics such as low driving voltage and low driving current. The driving voltage of OLED with O2-plasma treated ITO is 1.7V, and the driving current equals 8.95×10-9 A. Without treating by O2-plasma, the driving voltage equals 2.5V and the driving current is 4.51×10-7 A. We successfully integrated both OLED and OTFT on one substrate and made the samples based on MEH-PPV just by one spinning step. By this way, we could reduce the processing steps for active-matrix driving OLED.