Fabrication of Pixelated Organic Light‐Emitting Transistor (OLET) with a Pure Red‐Emitting Organic Semiconductor

Abstract A pure red‐emitting organic light‐emitting transistor (OLET) is successfully fabricated using a π‐extended dicyanodistyrylbenzene‐type organic semiconductor material (Hex‐4‐TFPTA), which shows outstanding charge transport and solid‐state luminescence at the same time. Based on the structural (X‐ray) and photophysical analyses, it is found that the appropriate molecular stacking and highly allowed S 1 →S 0 transition of Hex‐4‐TFPTA created the ambidextrous balance between electrical mobility ( µ e, FET ≈ 1 cm 2 V −1 s −1 ) and solid‐state luminescent quantum yield, even in the deep‐red (DR) region ( Φ F = 28%). Remarkably, the color purity of the red Hex‐4‐TFPTA thin film (0.70, 0.30) is close to the National Television System Committee (NTSC) standard primary red (0.67, 0.33) in Commission Internationale de I'Eclairage (CIE) color space. Moreover, in this work, micropixelated areal OLET emission is demonstrated for the first time by patterning the organic layer via a novel soft‐lithographic technique called “patterned taping.”