Efficient and stable solution-processed organic light emitting transistors using a high-k dielectric.

Abstract

We report the development of highly efficient and stable solution-processed organic light emitting transistors (OLETs) that combine a polymer heterostructure with the transparent high-k dielectric poly(vinylidenefluoride0.62-trifluoroethylene0.31-chlorotrifluoroethylene0.7) (P(VDF-TrFE-CTFE)). The polymer heterostructure comprises of the poly[4-(4,4- dihexadecyl-4H-cyclopenta[1,2-b:5,4-b’]dithiophen-2-yl)-alt-[1,2,5]thiadiazolo[3,4- c]pyridine] (PCDTPT) and Super Yellow as charge transporting and light emitting layers, respectively. Device characterization shows that the use of P(VDF-TrFE-CTFE) leads to larger channel currents (≈2 mA) and lower operating voltages (-35 V) than for previously reported polymer based OLETs. Furthermore, the combined transparency of the dielectric and gate electrode, results in efficient bottom emission with external quantum efficiency of ≈0.88 % at a luminance L ≥ 2000 cd m−2. Importantly, the resulting OLETs exhibit excellent shelf life and operational stability. The present work represents a significant step forward in the pursuit of all-solution-processed OLET technology for lighting and display applications.