Shi‐Jian Su

Simultaneous enhancement of open-circuit voltage, short-circuit current density, and fill factor in highly efficient polymer solar cells by incorporating an alcohol/water-soluble conjugated polymer as cathode interlayer is domonstrated. When combined with a low-bandgap polymer PTB7 as the electron donor material, the power efficiency of the devices is improved to certified 8.370%. Due to drastic improvement in efficiency and easy utilization, this method opens new opportunities for PSCs from various material systems to improve towards 10% efficiency. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not copy-edited or typeset. They are made available as submitted by the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Highly efficient blue and white OLEDs with reduced efficiency roll-off based on a carrier- and exciton-confining structure are developed. Record power efficiencies of 46 and 44 lm W−1 and an external quantum efficiency of 25% at the illumination-relevant luminance of 1000 cd m−2 are achieved for the blue and white OLEDs, respectively, without the use of any outcoupling techniques.

Abstract The vast market demands for applications of organic light‐emitting diodes (OLEDs) have quickened the pace of the search for future high‐performance materials, emphasizing the importance of exploring blue light‐emitting materials, which determine the performance bottleneck of OLEDs. Moreover, actualizing highly efficient, pure‐blue, stable, and purely organic electroluminescence will pave the way toward the realization of cost‐effective, high‐quality, and long‐lasting commercialized OLED displays and illumination applications. Without the aid of noble heavy metal atoms, the newly emerging thermally activated delayed fluorescent (TADF) materials can effectively utilize triplet excitons owing to the small singlet–triplet splitting energy (Δ E ST ) for rapid reverse intersystem crossing (RISC) process, leading to the achievement of 100% internal quantum efficiency under electrical operation. Nevertheless, fundamental scientific challenges with respect to simultaneously achieving stable pure‐blue emission, large radiative recombination rates with short exciton lifetimes and small Δ E ST continue to hinder the popularization of blue TADF materials. A review of the current state of blue TADF emitters is timely and underscores the key challenges that must be overcome toward the development of a stable, true‐blue TADF‐based electroluminescent application in the future.

Two pyridine-containing triphenylbenzene derivatives of 1,3,5-tri(m-pyrid- 3-yl-phenyl)benzene (TmPyPB) and 1,3,5-tri(p-pyrid-3-yl-phenyl) benzene (TpPyPB) (see figure) with high electron mobility and high triplet energy level were designed and synthesized. Highly efficient blue and green phosphorescent OLEDs were achieved by using TmPyPB and TpPyPB as an electron-transport layer, respectively.