Temperature dependence of carrier injection in small molecular organic light emitting device with a mixed single layer

► The carrier injection mechanism in mixed single layer OLED by mixing Alq3, PyPySPyPy, α-NPD and rubrene was investigated in the first time. ► The carrier injection mechanism at the interface was primarily ascribed to the Schottky thermionic emission with the barrier height of 0.25 eV for holes and 0.67 eV for electrons. ► The barrier height of the electron could be controlled by changing LUMO level of electron transport materials. ► The interfacial state analysis demonstrated that the electron barrier height was also dependent on the interfacial conditions of the devices.