Color stabilization in white organic light emitting devices utilizing trapping layers inserted in both an electron transport layer and an emitting layer.
The electrical and the optical properties of white organic light emitting devices (OLEDs) utilizing trapping layers inserted into both an electron transport layer (ETL) and an emitting layer (EML) were investigated. The current density of OLEDs with an ETL containing a 5,6,11,12-tetraphenylnaphthacene (rubrene) layer was slightly smaller than those of other devices. The luminance-current density and luminance efficiency-current density of the OLEDs with rubrene layers embedded in only an ETL or an EML were similar to the blue reference device. While the electroluminescence (EL) spectrum for the OLEDs with a rubrene layer in the ETL in the low voltage range showed the white color, that with rubrene layers in both the EML and the ETL exhibited white color, regardless of the applied voltage. The Commission International de l'Eclairage coordinates of the white OLEDs became stabilized by inserting rubrene layers into both the EML and the ETL.
Kwack
Byoung Chan
BC
Department of Information Display Engineering, Hanyang University, Seoul 133-791, Korea.
Lee
Kwang Seop
KS
Choo
Dong Chul
DC
Kim
Tae Whan
TW
Seo
Ji Hyun
JH
Kim
Young Kwan
YK