Patent ID: 7183010

Claim:
An organic light-emitting device, comprising: a) a substrate; b) an anode and a cathode disposed over the substrate; c) a luminescent layer disposed between the anode and the cathode wherein the luminescent layer includes a host and at least one dopant; d) the host of the luminescent layer being selected to include a solid organic material comprising a mixture of at least two components wherein: i) the first component of the mixture is an organic compound that is capable of transporting either electrons or holes or both and is capable of forming both monomer state and an aggregate state and further is capable of forming the aggregate state either in the ground electronic state or in the excited electronic state that results in a different absorption or emission spectrum or both relative to the absorption or emission spectrum or both of the monomer state, respectively, or the first component of the mixture is capable of forming the aggregate state whose presence results in a quantum yield of luminescence of the monomer state being different relative to the quantum yield of luminescence of the monomer state in the absence of the aggregate state, and ii) the second component of the mixture is an organic compound that upon mixing with the first host component is capable of forming a continuous and substantially pin-hole-free layer; iii) both the first and second components being selected to transfer excitation energy to the dopant so that the dopant produces light while the first and second components produce no light in the presence of the dopant; and e) the dopant of the luminescent layer being selected to produce light from the light-emitting device.