Nanostructured surfaces

Systematic study of luminescent nanostructured films on pre-modified substrates
Karbovnyk I.1, Turko B.2, Sadovyi B.2,3, Klym H.4, Kukhta I.5, Luchechko A.1, Kukhta A.6     
1Department of Electronics and Computer Technologies, Ivan Franko National University of Lviv, 107, Tarnavskogo Str., Lviv, 79000, Ukraine
E-mail: ivan_karbovnyk@yahoo.com
2Department of Physics, Ivan Franko National University of Lviv, 8, Kyryla i Mefodiia Str., Lviv, 79005, Ukraine
3Institute of High Pressure Physics PAS, 
29/37, Sokolowska Str., Warsaw, 01-142, Poland

4Department of Specialized Computer Systems,
Lviv Polytechnic National University, 12, Bandera Str., Lviv, 79013, Ukraine
5Institute of Chemistry of New Materials, 
National Academy of Sciences of Belarus, Minsk, Belarus,
6Institute for Nuclear Problems, Belarusian State University, 
11, Babruiskaya Str., Minsk, 220030, Belarus

Luminescent devices with aligned emitting elements are promising for development of innovative electronic products. Luminescent thin films with ordered molecules, for example, are considered very attractive as active parts of organic electroluminescent diodes with polarized emission. Molecular ordering in such structures is, however, strongly dependent on the substrate surface.
It is known that liquid crystalline elongated molecules, when aligned on a rubbed polymer surface, may have either in-plane or out-of-plane orientation. The in-plane alignment usually matches with the rubbing direction.
In this work, we systematically study oriented nanostructured films based on blue emitting organic liquid crystalline molecules 4-(n-penthyl)-3-chloro-4///-trifluoromethoxy-[1,1/, 4/, 1//, 4//, 1///- quarterphenyl], hereafter denoted as M-BLUE  obtained by thermal deposition in vacuum onto glass substrates pre-modified by polymer coating. Various aspects of film growth, alignment of molecules and luminescent properties are discussed.