A strong red-emitting carbazole based europium(iii) complex excited by blue light

Abstract

A novel 2-positional linked carbazole based β-diketone with methoxyl in the 7-position (EMOCTFBD), and its europium(III) ternary complex Eu(EMOCTFBD)₃phen were synthesized via a dexterously designed indirect routine, where EMOCTFBD was 1-(9-ethyl-7-methoxyl-9H-carbazol-2-yl)-4,4,4-trifluorobutane-1,3-dione and phen was 1,10-phenanthroline. Eu(EMOCTFBD)₃phen shows high thermal stability. The introduction of a methoxyl in the 7-position of the carbazole ring remarkably enhanced the excitation band intensity in the blue region, and the complex exhibited intense red emission under blue-light excitation. The lowest triplet state energy was measured and suggests the photoluminescence process as a ligand-sensitized luminescence process (antenna effect). A bright red-emitting diode was fabricated by coating the complex phosphor onto a ∼460 nm-emitting InGaN chip. All the results indicate that Eu(EMOCTFBD)₃phen is an interesting red-emitting material excited by blue light, and therefore may be applied in many fields without UV radiation.