Structural characterization of tetrahexyl sexithiophene ordered films grown by organic molecular beam deposition

The deposition of thin films of 3,3 ",4''',3'''''-tetrahexyl-2,2':5',2 ":5 ",2''':5''',2''''':5''''',2'''''-sexithiophene (4H6T) has been performed in ultra-high vacuum conditions by using organic molecular beam deposition (O MBD). Once temperature and pressure are optimized, the substrate choice is the key factor in determining the properties of the deposited films. From t he structural analysis of samples deposited on different inorganic and orga nic substrates as well as from the comparison with crystalline polymorphs o f 4H6T, useful information for the control of both structural order and mol ecular orientation in the films are inferred. The results of structural inv estigations by X-ray diffraction, compared with optical analyses (electroni c absorption and photoluminescence), are indicative of either intermolecula r or substrate-4H6T interactions. (C) 1999 Elsevier Science B.V. All rights reserved.