Mechanism of rubrene thin film growth using α-quaterthiophene inducing layer at low temperature

Growth of rubrene thin films at room temperature on bare SiO2 substrates and on top of a α-quaterthiophene (α-4T) inducing layer on SiO2 substrates was investigated. The rubrene thin films and α-4T inducing layers were prepared by vacuum deposition method and were characterized by atomic force microscopy and X-ray diffraction. Rubrene thin films directly deposited on SiO2 substrates had a number of holes on their surface, while the ones grown on top of a α-4T inducing layer on SiO2 substrates exhibited highly ordered morphology and structure. It was found that large-area and ordered rubrene thin films could properly match with the α-4T inducing layers in the prepared heterostructures. Two different rubrene film growth mechanisms were observed from results obtained for films with different thicknesses. We conclude that rubrene thin films prepared at low temperature using α-4T inducing layer on SiO2 substrates hold a great promise of application in large-area and flexible displays.