Optoelectronic Device, Use of a Dual Emitter as Wavelength Conversion Material

An optoelectronic apparatus comprising:

• at least one wavelength conversion region which comprises at least one dual emitter as wavelength conversion material, wherein the wavelength conversion region converts primary radiation at least in part into secondary radiation,
• wherein the dual emitter comprises a first electronic base state and a second electronic base state, together with a first electronically excited state and a second electronically excited state which is reachable from the first electronically excited state,
• wherein the dual emitter further comprises an emission proceeding from the second electronically excited state into the second base state, and
• wherein the dual emitter comprises molecules of the following general formulae:
• where RA and R1 to R4 are mutually independently selectable from hydrogen, alkyl or alkenyl groups, long-chain alkyl, alkoxy, long-chain alkoxy, cycloalkyl, haloalkyl, aryl, arylenes, haloaryl, heteroaryl, heteroarylenes, heterocycloalkylenes, heterocycloalkyl, haloheteroaryl, alkenyl, haloalkenyl, alkynyl, haloalkynyl, ketoaryl, haloketoaryl, ketoheteroaryl, ketoalkyl, haloketoalkyl, ketoalkenyl, haloketoalkenyl, or part of a cyclic, aromatic or heteroaromatic system.