Short Alkyl Chain Engineering Modulation on Naphthalene Flanked Diketopyrrolopyrrole toward High-Performance Single Crystal Transistors and Organic Thin Film Displays

Studying multi-purpose applications of a specific material is a challenging topic in the organic electronics community. In this work, through molecular engineering and smart device structure design strategy, high performance in transistors and thin film display devices is simultaneously achieved by applying a simple new dye molecule, naphthalene flanked diketopyrrolopyrrole (DPPN), as the active layer material. Short alkyl chains (hexyl or octyl side groups for H-DPPN and O-DPPN, respectively) are adapted to improve the hole mobility in organic thin film transistors (OTFTs) and single crystal transistors (SCTs). Specifically, H-DPPN shows a similar hole mobility in either OTFTs or SCTs, while O-DPPN exhibits a dramatically enhanced mobility, reaching 0.125 cm2 V−1 s−1 in SCTs. Additionally, a smart organic light emitting diode (OLED) device is designed by using DPPN molecule as the dopant with a host matrix. The promising external quantum efficiencies of 4.0% and 2.3% are achieved for H-DPPN and O-DPPN fabricated OLEDs. Overall, in this work, it is reported that DPP-based small molecules can simultaneously function well in both transistors and thin film displays with high device performance through molecular and smart device engineering.