Efficient Organe Organic Light-Emitting Devices Using N-arylbenzinmidzoles as Blocking Layer

Abstract

A orange organic light-emitting device has been fabricated with a structure of ITO/m-MTDATA (45 nm)/NPB (8 nm)/ DPVBi:DCJTB 0.5 % (15 nm)/TPBi (x nm)/Alq3 [(60-x) n /LiF (1 nm)/Al£¬where x=0, 4, 7 and 10, respectively. N-arylbenzinmidzoles (TPBi) was used as the excton-blocking layer resulting mixture of lights from DPVBi molecules (blue-light) and DCJTB (yellow-light) molecules, thereby producing orange light emission. The performance of device can be readily adjusted by only varying the thickness of the TPBi layer. The Commission Internationale de 1'Eclairage (CIE) coordinates of the device are largely insensitive to diffrent of the driving voltages. When the thickness of TPBi is 7 nm, the device exhibits peak efficiency of 6.16 cd/A at the applied voltage of 8 V, and the maximum brightness is 43310 cd/m2 at 15 V, respectively.