Structurally simple non-doped sky-blue OLEDs with high luminance and efficiencies at low driving voltagesElectronic supplementary information (ESI) available: Additional electroluminescence spectra of the OLED devices, crystallographic data and copies of NMR spectra. CCDC 1520271 and 1520272. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c6tc05639c

• Main Authors: Li, Chenglong, Li, Zhiqiang, Yan, Xianju, Zhang, Yuewei, Zhang, Zuolun, Wang, Yue
• Format: Article
• Language: English
• ISSN: 2050-7526; 2050-7534
• DOI: 10.1039/c6tc05639c

Blue organic light-emitting diodes (OLEDs) are crucial for flat-panel displays and solid-state lighting. Regarding the practical application of OLEDs, high luminance and efficiencies at a low driving voltage, as well as a simple device structure, are highly desirable. However, blue OLEDs fulfilling these requirements are rare. Herein, two new sky-blue emitters, TPA-An-PPI and PCz-An-PPI, with the integration of wide-bandgap phenanthro[9,10- d ]imidazole, anthracene and aromatic amine groups have been synthesized. They possess good thermal stability, bright emission in the solid state, as well as the bipolar carrier-transporting ability. Structurally simple non-doped sky-blue OLEDs with TPA-An-PPI as the emitting layer showed high performance, with the maximum luminance ( L max ) of 51 390 cd m −2 , the maximum power efficiency (PE max ) of 10.42 lm W −1 , and the maximum external quantum efficiency (EQE max ) of 4.61%. More importantly, at a practical high luminance of 1000 cd m −2 , the PE and EQE retained high values of 8.48 lm W −1 and 4.60%, respectively, and the corresponding driving voltage was as low as 3.6 V. The performance of the non-doped device based on PCz-An-PPI was also high, although being lower than that of TPA-An-PPI. Two emitters that can realize structurally simple non-doped sky-blue OLEDs with high brightness and efficiencies at low driving voltages have been designed and synthesized.