Transition Metal Dichalcogenide‐Based Transistor Circuits for Gray Scale Organic Light‐Emitting Displays

Two types of transition metal dichalcogenide (TMD) transistors are applied to demonstrate their possibility as switching/driving elements for the pixel of organic light-emitting diode (OLED) display. Such TMD materials are 6 nm thin WSe2 and MoS2 as a p-type and n-type channel, respectively, and the pixel is thus composed of external green OLED and nanoscale thin channel field effect transistors (FETs) for switching and driving. The maximum mobility of WSe2-FETs either as switch or as driver is ≈30 cm2 V−1 s−1, in linear regime of the gate voltage sweep range. Digital (ON/OFF-switching) and gray-scale analogue operations of OLED pixel are nicely demonstrated. MoS2 nanosheet FET-based pixel is also demonstrated, although limited to alternating gray scale operation of OLED. Device stability issue is still remaining for future study but TMD channel FETs are very promising and novel for their applications to OLED pixel because of their high mobility and ID ON/OFF ratio.