High-efficiency host free deep-blue organic light-emitting diode with double carrier regulating layers

Abstract A bright high-efficiency host-free deep-blue organic light-emitting diode (OLED) is demonstrated. Without the aid of any carrier regulating layer, the deep-blue OLED shows a power efficiency of 1.7 lm W −1 with CIE coordinates of (0.143, 0.098) at 1000 cd m −2 . The respective power efficiency is increased from 1.7 to 2.1 and 2.2 lm W −1 as a single- and double-carrier regulating layers were incorporated. The respective peak luminance also increases from 5250 to 7620 and 9130 cd m −2 , an increment of 45% and 74%. The marked brightness improvement may be attributed to the incorporated carrier regulating layers that effectively lead carriers to recombine in a wider zone. Moreover, the blue emission can be hypsochromic shifted by varying the incorporation position of the carrier regulating layer and the emissive layer thickness.