Sol-gel encapsulation of molecules to generate functional optical materials: A molecular programming approach

The extraordinary opportunities offered by integrating solution chemistry of molecular entities with the solid- state nature of the gel provide the basis for designing a number of novel molecular materials. Herein, we present a strategy based on encapsulation of suitable response active species to impart useful optical properties to sol - gel glasses. The basic concept of this molecular programming approach is based on deliberate incorporation of response- active species in the silica gel framework to elicit specific optical responses. Design of molecular materials for device applications depends on selection of molecules which exhibit well- defined electronic or optical response, and assembly of these molecular components into a geometric structure that retains the rigidity, addressability, and stability necessary for practical applications. The approach is based on using molecules as active species and sol gel glass as structural matrix in which the molecules are selectively integrated. A designer approach that employs specific molecules for generating optical signals is described. As such the properties of these silica- based glasses can be tuned by varying the composition of encapsulated species. These modified glasses exhibit substantially altered optical properties as compared to pristine silica sol - gels. The optical response of these materials provide initial examples toward designing novel materials whose optical and/ or photonic responses can be modulated by structural integration of specific dopant entities.