Lowest energy Frenkel and charge transfer exciton intermixing in one-dimensional copper phthalocyanine molecular lattice

We report the results of the combined experimental and theoretical studies of the low-lyingexciton states in crystallinecopper phthalocyanine. We derive the eigenenergyspectrum for the two lowest intramolecularFrenkel excitons coupled to the intermolecularcharge transferexciton state and compare it with temperature dependent optical absorptionspectra measured experimentally, to obtain the parameters of the Frenkel-charge-transferexciton intermixing. The twoFrenkel exciton states are spaced apart by 0.26  eV, and thecharge transferexciton state is 50  meV above the lowestFrenkel exciton. BothFrenkel excitons are strongly mixed with thecharge transferexciton, showing the coupling constant 0.17  eV which agrees with earlier experimental measurements. These results can be used for the proper interpretation of the physical properties of crystalline phthalocyanines.

Source: Applied Physics Letters - November 23, 2016 Category: Physics Authors: I. V. Bondarev, A. Popescu, R. A. Younts, B. Hoffman, T. McAfee, D. B. Dougherty, K. Gundogdu and H. W. Ade Source Type: research