A group of Dongge Ma from Chinese Academy of Sciences has reported an efficient way to increase the thickness of solution processed small molecule based electron-transmiting layer in yellow PLEDs. Solution-phase processing would be a highly desirable method of multilayer diode manufacturing as it's much easier and cheaper to perform. They have noted that commonly chosen electron-transmitting materials ( TmPyPB, TAZ and TPBL) can only produce a maximum of 15 nm thick electron-transmitting layer when processed in solution. That makes corresponding fabricated diodes reach their efficiency lim it quickly. Interestingly, when mixture of various compositions of these small molecules were tested, ideal combination was discovered. The TPBI:TnPyPB:TAZ mixture (1.3:0.7:1 w/w) allowed to obtain 40 nm thick layer and reach external quantum efficiency of 41.7 cd/A and 12.7%. The maximum brightness was 23926 cd/m2.
The original article and supporting information were published by ACS Applied Materials & Interfaces:
Efficient Phosphorescent polymer Yellow-Light-Emitting Diodes Based on Solution-Processed Small Molecule Electron Transporting Layer
Tengling Ye, Shiyang Shao, Jiangshan Chen, Lixiang Wang, Dongge Ma