Solution-processable phosphorescent materials
A material capable of luminescence comprising a polymer or oligomer and an organometallic group, wherein the polymer or oligomer is at least partially conjugated and the organometallic group is covalently bound to the polymer or oligomer and at least one of the nature, location, and proportion of the polymer or oligomer and of the organometallic group in the material are selected so that the luminescence predominantly is phosphorescence.
1. A process for preparing a material capable of luminescence, wherein the luminescence predominantly is phosphorescence, said material comprising a polymer or oligomer and an organometallic group, the organometallic group being covalently bound to the polymer or oligomer only at end-capping positions of the polymer or oligomer, wherein the organometallic group is present in the material in an amount between 1 weight percent and 10 weight percent; said process comprising:
(a) reacting monomers to form a polymer or oligomer wherein each monomer has at least two reactive groups selected from the group consisting of a halide group, a boronic acid group, a boronic ester group, and a borane group, and each monomer comprises an aryl or heteroaryl group; and
(b) terminating the polymer or oligomer formed in step (a) using an end-capping reagent, said end-capping reagent comprising one reactive group selected from the group consisting of a halide group, a boronic acid group, a boronic ester group, and a borane group, said end-capping reagent further containing the organometallic group.
2. A process according to claim 1 , wherein the polymer or oligomer is at least partially conjugated.
3. A process according to claim 1 , wherein the polymer or oligomer is linear.
4. A process according to claim 1 , wherein the luminescence is electroluminescence.
5. A process according to claim 1 , wherein the polymer or oligomer is semiconducting.
6. A process according to claim 5 , wherein the aryl or heteroaryl group comprises a group selected from the group consisting of 2,7-linked 9,9 disubstituted fluorenes, p-linked dialkyl phenylenes, p-linked disubstituted phenylenes, phenylene vinylenes, 2,5-linked benzothiadiazoles, 2,5-linked substituted benzothiadiazoles, 2,5-linked disubstituted benzothiadiazoles, 2,5-linked substituted thiophenes, unsubstituted thiophenes, and triarylamines.
7. A process according to claim 1 , wherein the organometallic group contained in the end-capping reagent contains a transition metal.
8. A process according to claim 7 , wherein the organometallic group contained in the end-capping reagent contains a precious metal.