Co-crystals with high fluorescence quantum yield

New fluorescent co-crystals based on 1,8-naphthalimide derivatives and halogenated co-formers. Thanks to their high fluorescent yields said co-crystals can be used as fluorescent compounds in many solid state technologies.

Title of the patent Co-crystal with high fluorescence yield based on 1,8-naphtalimide derivatives and halogenated co-formers
Thematic area Chemistry and biotechnology
Ownership Alma Mater Studiorum- Università di Bologna e Consiglio Nazionale delle Ricerche
Inventors Dario Braga, Fabrizia Grepioni, Simone D’Agostino, Luca Catalano, Alessio Bertocco, Barbara Ventura
Protection Italy
Licensing status Available for licensing agreement
Keywords Organic co-crystal, halogen bond, solid state fluorescence, fluorescence quantum yield, dyestuff
Filed on Jun 20, 2014

Purely organic luminescent materials constitute an attractive field of research. More in particular, solid luminescent materials are of particular interest since they are cheap, easy to synthesize and can find use in a variety of applications, for example solid state lighting technologies, such as OLED devices. A further possible interesting field of application of solid luminescent organic compounds is as down-conversion materials in solar cells. The luminescence features of organic solids strongly depend on the arrangement of the molecules in the solid-state. There is still the need of organic compounds showing a good emission yield in the solid state, in particular there is the need of compounds suitable for use in the solid-state applications.

The inventors have been able to modify the solid state optical properties of organic cromophores via co-crystal formation; the co-former is an organic molecule able to form halogen bonding interactions with the chromophore. On passing from the starting chromophore to the co-crystalline product, it can be observed a sensible enhancement of the fluorescence quantum yield.

Improvement of the fluorescence quantum yield implies a better efficiency of the emission of the cromophores and less energy loss. This is a critical point for applicative purposes.