Abstract
An anthracene aromatic unit was introduced into the phenylethynyl structure by a rigid acetylene linkage at the C-9 and C-10 positions via Sonogashira coupling reactions, resulting in a planar and straight-backbone molecule (9,10-bis((4-((3,7-dimethyloctyl)oxy) phenyl) ethynyl) anthracene) (BPEA). Thermogravimetric analysis demonstrated the good thermal stability of the BPEA. Photoluminescence analysis showed that a suitable expanded π-conjugation in the BPEA made its excitation band extend into the visible region, and an intense green emission was observed under blue-light excitation. A bright green light-emitting diode with an efficiency of 18.22 lm/w was fabricated by coating the organic phosphor onto a 460 nm-emitting InGaN chip. All the results indicate that BPEA is a useful green-emitting material which is efficiently excited by blue light, and therefore, that it could be applied in many fields without UV radiation.
Highlights
Light-emitting diode (LED) lamps using phosphor conversion of 350–480 nm LED radiation have drawn much attention, and are notably expected to replace traditional illumination sources due to their superior features such as low power consumption, long lifetime, high efficiency, small volume, and low maintenance [1,2,3]
A thermogravimetric analysis (TGA) and differential thermogravimetric (DTG) techniques were employed to investigate the thermal stability of the synthesized compound
The emission at around 460 nm from the InGaN chips was completely absorbed in the spectrum of the LED with BPEA, indicating that the organic phosphor can be efficiently excited by blue light from the ~460 nm-emitting InGaN chips
Summary
Light-emitting diode (LED) lamps using phosphor conversion of 350–480 nm LED radiation have drawn much attention, and are notably expected to replace traditional illumination sources due to their superior features such as low power consumption, long lifetime, high efficiency, small volume, and low maintenance [1,2,3]. It has been reported that some phenyl acetylene molecules could show unique intermolecular aggregation through coplanar interactions, leading to efficient charge transport, fast energy transfer, and excellent luminescence properties, both in solution and in a solid state [15,16]. Their highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) energy gaps and emissive properties can be controlled by tuning their effective conjugation lengths [17,18]. A bright green-emitting LED was fabricated by coating the BPEA onto a 460 nm-emitting InGaN chip
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