We achieved extremely-high-density steady state carrier injection and transport at over ~10000 A cm2 into organic thin films using high thermally conductive substrates, which suppress the temperature rise inside the devices by transferring the joule heat into the substrates. Using a silicon substrate with a high thermal conductivity of 148 WmK and a small size cathode with a radius of r=25 μm, we achieved a maximum current density of Jmax =12222 A cm2 and power density of Pmax ~ 105 W cm2 in an ITO (110 nm) copper phthalocyanine (CuPc) (25 nm) MgAg (100 nm) Ag (10 nm) device during a fraction of a second under direct current sweep. Further, we also achieved Jmax =514 A cm2 in a conventional organic light-emitting diode structure using the same techniques. In the CuPc based devices, we observed characteristic current density (J) -voltage (V) behavior, indicating that the J-V characteristics are controlled by the trap-free space-charge-limited currents in the high current region, and by the trapped-charge-limited current in the low current region.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)