Melting Effect of Hole-Injecting Layer on the Performance of Passive Matrix Organic Light-Emitting Displays

ABSTRACT

Here we report improved operation stability of passive matrix organic light-emitting displays (PM-OLED) by melting a hole-injecting layer (HIL) that is the first organic layer contacting anode. The PM-OLED displays fabricated in this work are consisted of 128􀀁128 pixels in which each pixel has a dimension of 200μm􀀁200μm. The exact thermal transition behaviour of hole-injecting material was first examined using a differential scanning calorimeter in order to decide the melting temperature for the HIL melting process (300oC/3min). Results show that the display with the untreated (ascoated) HIL exhibited large leakage current which eventually resulted in damages (black cross-talk lines) to the display during operation. However, no cross-talk defect was observed for the PM-OLED display with the thermally treated (melted) HIL, which was supported by the absence of leakage current at reverse bias.