The effect of alpha-sexithiophene (alpha-6T) layers on the light emitting diode (LED) were studied. The alpha-6T was used for a buffer layer in electroluminescent (EL) devices. Enhanced carrier (hole) injection and improved emission efficiency were observed. Carrier injection characteristics were investigated as a function of alpha-6T layer thickness. The efficiency of the electroluminescence was proportional to the thickness of alpha-6T layer. The highest efficiency was observed at 600 Angstrom of alpha-6T layer, which was about 1.5 times higher than that of device without alpha-6T layer. The device with alpha-BT layer showed an operating voltage lowered by 2 V. The alpha-6T layer can substitute hole blocking layer, and control charge injecting properties.