The effect of a-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 ${alpha}-6T$ later thickness. The efficiency of the electroluminescence was proportional to the thickness of ${alpha}-6T$ layer. The highest efficiency was observed 600A of ${alpha}-6T$ later, which was about 1.5 times higher than that of device without ${alpha}-6T$ later. The device with a-6T showed an operation voltage lowered by 2V. The ${alpha}-6T$ layer can substitute hole blocking layer, and control charge injection properties.