Structure of pentacene/tetracene superlattices deposited on glass substrate

Pentacene/tetracene organic superlattices were formed by deposition on a glass substrate, and their structure was investigated by x-ray diffraction and photoluminescence. For samples in which the number (n) of constituent pentacene (or tetracene) molecular layers within a period is such that n≥3, the first-order x-ray diffraction peak was found to consist of several equally spaced subpeaks. Comparison of the spectra with calculated structure factors established that a well-defined superlattice structure was achieved in these samples. In contrast, samples with n<3 showed no evidence of superlattice formation. Photoluminescence spectra show clear correlation with the x-ray results.