n型掺杂PTCDA复合材料对有机发光二极管性能的提高

采用碳酸锂(Li2CO3)为n型掺杂剂,苝四甲酸二酐(3,4,9,10 perylenetetracarboxylic dianhydride,PTCDA)为母体材料,通过真空热蒸发方式制备了n型掺杂的PTCDA复合材料,将其作为电子注入材料应用到NPB/Alq3异质结有机电致发光器件中.研究发现,同LI2CO3:BC...

Lithium Carbonate Doped 3,4,9,10-perylenetetracarboxylic Dianhydride for Enhanced Performance in Organic Light Emitting Diode

Lithium carbonate doped 3,4,9,10-perylenetetracarboxylic dianhydride (Li₂CO₃ ∶ PTCDA) was fabricated as electron injection layer in NPB/Alq₃ heterojunction based organic light emitting diodes (OLEDs). It was found that the current of OLED using Li₂CO₃ ∶ PTCDA was strongly dependent on the Li₂CO₃ doping concentration. The OLED using Li₂CO₃ ∶ PTCDA(1 ∶ 1) with Al as the cathode exhibits an improved power efficiency and significantly increased luminance, comparing with the one using Li₂CO₃ ∶ BCP(1 ∶ 4) with Al as the cathode and the one using the regular LiF/Al cathode.It is because the electron conductivity for Li₂CO₃ ∶ PTCDA/(1 ∶ 1) is much higher than that Li₂CO₃ ∶ BCP(1 ∶ 4) and neat Alq₃. In addition, it is found that there exist a Schottky barrier at the intrinsic interface of Alq₃ and Li₂CO₃ ∶ PTCDA(1 ∶ 1), which suppress the electron transfer from Li₂CO₃ ∶ PTCDA(1 ∶ 1) into Alq₃. However, the release of Li atoms upon the Al deposition onto 1 ∶ 1 Li₂CO₃ ∶ PTCDA could turn the interface into an ohmic contact, thereby delivering efficient electron injection from Li₂CO₃ ∶ PTCDA(1 ∶ 1) into Alq₃. We provided a class of high-function, low-cost, and easily fabricated n-doped material for the performance enhancement of OLEDs.