Knowledge Bank

“Solutions of carbazole at $10-4M$ concentration in rigid glasses at $77\circ K$ emit strongly. In alcoholic media, the addition of acridine to the system has little effert. However in a hydrocarbon glass, equimolar quantities of acridine strongly quench the carbazole emission. This is interpreted as resulting from the formation of hydrogen bonded dimers between acridine and carbazole, and consequent interactions of the $\pi$-systems of the two molecules. This strong quenching by the acridine is still found if the Carbazole concentration is raised to $4\times 10-4$M, with the acridine concentration kept at $1\times 10-4$M. Here it is apparent that even the emission of the free carbazole molecules is being quenched, suggesting that the dimers may be acting as energy sinks.”