Comparative photophysical properties of poly(diphenylacetylene)s with different central atoms in side group

Polydiphenylacetylene (PDPA) derivaitves consisting of different central atoms of C, Si, and Ge in the pendent group were comparatively investigated in normal, swollen, and acid-treated states. The Ge-containing PDPA was more emissive than the other two both in solution and in solid states. All the polymers showed emission enhancement in a swollen state: The PL quantum yields increased remarkably when swollen in an appropriate non-solvent. The Si and Ge atoms were easily removed from the polymer chain under acidic condition, as a result, the PL intensity was significantly decreased and the polymers turned to be insoluble in common organic solvents. Although the tert-butyl group of C-containing PDPA remained intact during the acid exposure, similar PL attenuation occurred.