| abstract |
An OLED and a flat panel display, the OLED including an anode; a cathode; and an organic, the organic layer including an EML, the EML including first and second hosts, a hole transport region between the anode and the EML and including at least one of a hole injection layer (HIL), a hole transport layer (HTL), a buffer layer, or an electron blocking layer (EBL), an electron transport region between the EML and the cathode, the electron transport region including at least one of a hole blocking layer (HBL), an electron transport layer (ETL), or an electron injection layer (EIL), and an intermediate layer between the EML and the electron transport region; wherein an electron affinity of a compound of the intermediate layer [EA intermediate layer ] and an electron affinity of the first host [EA host1 ] satisfy a relationship represented by the following expression: n EA intermediate layer ≧EA host1 +0.3 eV. |