Lee Seok Jae, Koo Ja Ryong, Lim Dong Hwan, Park Hye Rim, Kim Young Kwan, Ha Yunkyoung
Department of Information Display, Hongik University, Seoul 121-791, Korea.
J Nanosci Nanotechnol. 2011 Aug;11(8):7151-4. doi: 10.1166/jnn.2011.4846.
We demonstrated efficient and stable white phosphorescent organic light-emitting diodes (OLEDs) with double-emitting layers (D-EMLs), which were comprised of two emissive layers with a hole transport-type host of N,N'-dicarbazolyl-3,5-benzene (mCP) and a electron transport-type host of 2,2',2"-(1,3,5-benzenetryl)tris(1-phenyl)-1H-benzimidazol (TPBi) with blue/orange emitters, respectively. We fabricated two type white devices with single emitting layer (S-EML) and D-EML of orange emitter, maintaining double recombination zone of blue emitter. In addition, the device architecture was developed to confine excitons inside the D-EMLs and to manage triplet excitons by controlling the charge injection. As a result, light-emitting performances of white OLED with D-EMLs were improved and showed the steady CIE coordinates compared to that with S-EML of orange emitter, which demonstrated the maximum luminous efficiency and external quantum efficiency were 21.38 cd/A and 11.09%. It also showed the stable white emission with CIE(x,y) coordinates from (x = 0.36, y = 0.37) at 6 V to (x = 0.33, y = 0.38) at 12 V.
我们展示了具有双发射层（D-EML）的高效稳定的白色磷光有机发光二极管（OLED），其由两个发射层组成，分别具有空穴传输型主体N，N'-二咔唑基-3,5-苯（mCP）和电子传输型主体2,2'，2''-（1,3,5-苯三基）三（1-苯基）-1H-苯并咪唑（TPBi）以及蓝色/橙色发射体。我们制造了两种类型的白色器件，分别具有橙色发射体的单发射层（S-EML）和D-EML，同时保持蓝色发射体的双重组区。此外，通过控制电荷注入来开发器件结构，以将激子限制在D-EML内部并管理三重态激子。结果，与具有橙色发射体S-EML的器件相比，具有D-EML的白色OLED的发光性能得到改善，并且显示出稳定的CIE坐标，其最大发光效率和外量子效率分别为21.38 cd/A和11.09%。它还显示出稳定的白色发射，CIE（x，y）坐标从6 V时的（x = 0.36，y = 0.37）到12 V时的（x = 0.33，y = 0.38）。
