Efficient blue electroluminescence of silylene-bridged 2-(2-naphthyl)indole

Abstract

We synthesised 12,12-diisopropyl-7-methyl-12H-indololo[3,2-d]-naphtho [1,2-b][1]silole from 1-bromo-2-naphthol via four steps. The silylene-bridged 2-(2-naphthyl)indole exhibited intense blue photoluminescence in solution and in the solid state. For example, the fluorescence maximum of the powder appeared at 476 nm with a high quantum yield (F ¼ 0.70). The organic light-emitting device using the silylene-bridged indole as a light-emitting layer demonstrated a high current efficiency of 3.80 cd A À1 and a power efficiency of 3.64 lm W À1 at 10 mA cm À2 with excellent colour coordinates (0.152, 0.094), while the device fabricated with the blue-emissive indole as a dopant achieved even higher current and power efficiencies of 6.68 cd A À1 and 5.58 lm W À1 , respectively, at 10 mA cm À2 .

Silicon-Bridged Biaryls: Molecular Design, New Synthesis, and Luminescence Control

“…53 Meanwhile, silicon-bridged biaryls can serve as key components of not only light-emitting devices, but also FET, 7 solar cells, 8 and solid fluorescent sensors. 9 Hence, the application of our designed silicon-bridged biaryls to charge transporting and sensing devices is also planned.…”

Synthesis of Siloles (and Germoles) that Exhibit the AIE Effect

“…In cases where devices containing metalloles and metallafluorenes were prepared and properties measured, generally only one or two configurations are described in a report and there does not seem to be an effort to maximize the performance of the device. There are exceptions to this observation, of course, including the study by Marks and co-workers [77c], and another example appeared in a recent report on silylene-bridged 2-(2-naphthyl)indole [79].…”

Dibenzosiloles and 12H‐Indololo[3,2‐d]naphtho[1,2‐b][1]siloles: Exploration of Organic Chromophores Exhibiting Efficient Solid‐State Fluorescence

“…Gratifyingly, indoles 21 were a novel class of compounds and were intensely blue emissive, particularly in the solid state [28]. Subsequently, we studied extensively the crystal structures, photophysical properties, redox properties, and molecular orbitals of 21 , and concluded that 3,2′‐diorganosilylene‐bridged 2‐arylindoles, including naphthyl derivatives 22 , have great potential as blue emitters for application to EL devices [29]. Since the chemistry of 21 was previously reported,[30] this section focuses on the properties and applications of 22 .…”

“…Because 22 exhibited high efficiency of fluorescence as a powder and in a doped PMMA film, we examined the performances of EL devices in which 22a was used as an emitting layer (EML; device I ) and a dopant in a host material (devices II – IV ) [29]. The structures of the devices are shown in Figure .…”

“…The EL data of the devices with a current density of 10 mA cm –2 are summarized in Table , and normalized electroluminescence spectra and current efficiency–current density plots of the devices are shown in Figures and , respectively [29]. Device I emitted blue light with a maximum at 471 nm and CIE coordinates of (0.152, 0.094).…”