Excited singlet state relaxation yields of pentacene in Shpolʹskii matrices

We studied absorption and fluorescence spectra and decays of pentacene (Pc) in Shpolʹskii matrices of n-heptane (C7), n-nonane (C9), n-decane (C10), n-dodecane (C12), n-tetradecane (C14) and n-hexadecane (C16) in the temperature range 1.7–200 K. The fluorescence quantum yields of Pc in C12, C14 and C16 at 1.7 K were determined to be 20±6%, 26±6% and 22±6%, respectively. The kinetic analysis provided values of the radiative, internal conversion and intersystem crossing rate constants for the relaxation channels of the S1 state of Pc in different matrices. Calculated fully saturated emission rates of single molecule were in very good relation with previous observation of single Pc molecules in Shpolʹskii matrices.