Silicon‐Based Material with Spiro‐Annulated Fluorene/Triphenylamine as Host and Exciton‐Blocking Layer for Blue Electrophosphorescent Devices

Abstract

A novel silicon-based compound, 10-phenyl-2'-(triphenylsilyl)-10H-spiro[acridine-9,9'-fluorene] (SSTF), with spiro structure has been designed, synthesized, and characterized. Its thermal, electronic absorption, and photoluminescence properties were studied. Its energy levels make it suitable as a host material or exciton-blocking material in blue phosphorescent organic light-emitting diodes (PhOLEDs). Accordingly, blue-emitting devices with iridium(III) bis[(4,6-difluorophenyl)-pyridinato-N,C(2)']picolinate (FIrpic) as phosphorescent dopant have been fabricated and show high efficiency with low roll-off. In particular, 44.0 cd A(-1) (41.3 lm W(-1)) at 100 cd m(-2) and 41.9 cd A(-1) (32.9 lm W(-1)) at 1000 cd m(-2) were achieved when SSTF was used as host material; 28.1 lm W(-1) at 100 cd m(-2) and 20.6 lm W(-1) at 1000 cd m(-2) were achieved when SSTF was used as exciton-blocking layer. All of the results are superior to those of the reference devices and show the potential applicability and versatility of SSTF in blue PhOLEDs.

Novel Carbazole/Fluorene-Based Host Material for Stable and Efficient Phosphorescent OLEDs

“…These efforts led to the development of high E T host materials containing the tetraphenylsilane moiety. − In 2004, Forrest, Thompson, and co-workers reported the first series of tetraphenylsilane-based host materials with E T of ∼3.5 eV, and successfully fabricated a deep blue OLED doped with FIr6 ( E T : 2.72 eV) with EQE up to ∼10% . Subsequently, several other types of Si-based host materials incorporating carbozale, − triphenylamine, , oxadizole, carbazole/diphenylphosphine oxide, or spiro-annulated fluorene/triphenylamine moiety, , were also developed. Most of these Si-based host materials were compatible with the blue emitter, FIrpic with E T of 2.65 eV, to achieve an EQE of 13.1–18.7%. − …”

“…Subsequently, several other types of Si-based host materials incorporating carbozale, − triphenylamine, , oxadizole, carbazole/diphenylphosphine oxide, or spiro-annulated fluorene/triphenylamine moiety, , were also developed. Most of these Si-based host materials were compatible with the blue emitter, FIrpic with E T of 2.65 eV, to achieve an EQE of 13.1–18.7%. − …”

84% efficiency improvement in all-inorganic perovskite light-emitting diodes assisted by a phosphorescent material

“…The corresponding characteristics data about the repeatability of the devices are summarized in Table S1. † The Device B emits green light from only CsPbBr 3 despite of FIrpic (peaked at 470 nm) 22 with high color purity of FWHM ∼18 nm and a peak intensity located at 522 nm, as shown in Fig. 1(c) .…”

Hosts for High‐Performance Phosphorescent Organic Light‐Emitting Diodes Based on Carbazole Derivatives

“…Especially, PHO-LEDs make it possible to achieve internal quantum efficiency of 100 %, and how to develop a host with suitable E T value and charge-transporting ability is the key to improve the performance of PHOLEDs. Carbazole-based chromophores are widely used in the synthesis of highly efficient hosts for PHOLEDs due to their high E T value and hole-transporting functionality [55] and there is still room to improve. The device performance of PHOLEDs is strongly correlated with device structure and the hosts used.…”