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A Step Beyond BRET: Fluorescence by Unbound Excitation from Luminescence FUEL
Published on: May 23, 2014
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Red Luminescent Eu(III) Coordination Bricks Excited on Blue LED Chip
Toru Koizuka1, Kei Yanagisawa, Yuichi Hirai
1Semiconductor Development Division , Nichia Corporation , 1-1 Tatsumi , Anan, Tokushima 774-0001 , Japan.
Inorganic Chemistry
|June 5, 2018
Summary
Three novel red luminescent Europium(III) complexes were synthesized for white light-emitting diode (LED) applications. The brick-type complex demonstrated exceptional photosensitized quantum yield and sensitization efficiency, crucial for advanced LED devices.
Area of Science:
- Materials Science
- Inorganic Chemistry
- Photochemistry
Background:
- Europium(III) complexes are investigated for their luminescent properties, particularly for applications in solid-state lighting.
- Schiff base and hexafluoroacetylacetonate (hfa) ligands play a crucial role in tuning the photophysical properties of lanthanide complexes.
- Developing efficient red emitters is essential for achieving white light emission in light-emitting diodes (LEDs).
Purpose of the Study:
- To synthesize and characterize three distinct red luminescent Europium(III) complexes incorporating Schiff base and hfa ligands.
- To evaluate the photophysical properties, including photosensitized quantum yield and sensitization efficiency, of these complexes for LED applications.
- To investigate the potential of these complexes as red emitters in white LED devices.
Main Methods:
- Synthesis of mononuclear, brick-type, and polynuclear Europium(III) complexes using Schiff base and hfa ligands.
- Photoluminescence spectroscopy to characterize the emission properties and excited state dynamics.
- Fabrication of prototype LED devices by mounting the most efficient complex onto an InGaN blue LED chip.
Main Results:
- Three red luminescent complexes were successfully synthesized: mononuclear [Eu(hfa)2(OAc)(salen)2], brick-type [Eu2(hfa)4(OAc)2(salbn)2], and polynuclear [Eu(hfa)2(OAc)(salhen)]n.
- The brick-type complex [Eu2(hfa)4(OAc)2(salbn)2] exhibited a photosensitized quantum yield (Φπ-π*) of 47% and a high sensitization efficiency (ηsens) of 96% when excited by blue light (460 nm).
- Ligand-ligand interactions within the excited state of the Schiff base and hfa ligands were identified as the cause for the high sensitization efficiency.
Conclusions:
- The synthesized Europium(III) complexes show promise as red emitters for white LED applications.
- The brick-type complex [Eu2(hfa)4(OAc)2(salbn)2] demonstrates superior performance, making it a strong candidate for efficient red light emission.
- The findings highlight the importance of ligand design in optimizing the luminescent properties of Europium(III) complexes for optoelectronic devices.
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