XJTU professor Wu Chaoxin and his team studied an inverted bottom-emitting WLEDs device structure with a thick hole transport layer (HTL), realizing the hole injection with high-performance and suppressing SP mode energy loss. Combined with conventional external light extraction technology, a record maximum forward-viewing PE of 228.4 lm/W was obtained in thick inverted devices with HTL of 240 nm, exhibiting significant enhancements of 57%, compared to counterpart devices of 60 nm. Meanwhile, at the brightness of 1000cd m-2, a record maximum forward-viewing PE of 166.3 lm/W was obtained. The result was certified as 165 lm/W by the third-party testing and analysis center of Suzhou Institute of Nanotechnology, Chinese Academy of Sciences. This is the highest international record and the world's brightest white organic light-emitting diodes.

The study was recently published in the international journal Nano Energy, titled Inverted Bottom-Emitting White Organic Light-Emitting Diodes with Power Efficiency over220 lm W-1. The first author is Dr. Yu Yue, with XJTU Professor Wu Chaoxin, Associate Professor Jiao Bo, and Professor Feng Minqiang of Suzhou University the co-corresponding authors. XJTU is the institutional affiliation of the first author and the first corresponding author.