White light emission from a two-component hybrid gel via an energy transfer process

A two-component light-harvesting organogel containing a naphthalimide-based gelator (1) as a donor and a phosphorescent Ir(III) complex [Ir(bt)2(acac)] (bt = 2-phenylbenzothiazole and acac = acetylacetone) (Ir) as an acceptor was used to produce white-light-emitting organogels. The addition of complex Ir to the gel 1 had a certain effect on the self-assembly behaviour of molecule 1, but did not affect the gelation ability, mechanical strength and structure surface wettability of the gel. The optical properties of the two-component gel 1-Ir could be tuned via high intermolecular energy transfer efficiency between 1 and complex Ir, which was confirmed by geometry optimizations and harmonic vibrational analyses. The white-light-emitting organogel was obtained with the molar ratio of complex Ir in the range of 0.3-1.0. In particular, the gel 1-Ir with the addition of 0.5 equivalent of Ir could emit white-light with the Commission Internationale de L' eclairage (CIE) coordinates of 0.33 and 0.31 under the excitation of 374 nm light.