1990 Volume 47 Issue 10 Pages 801-807
An apparatus was constructed to observe the in situ vacuum-deposition process of fluorescent organic compounds by means of fluorescence spectroscopy. A home-made fluorescence spectrometer was set-up, having a vacuum chamber with six windows, and fluorescence spectra of deposited films in the vacuum chamber were measured in situ during deposition. As an application, the deposition of 10- (1-pyrenyl) decanoic acid is reported here. The compound molecule evaporated and deposited one by one. Excimer sites of pyrenyl chromophores were formed in the layer near substrates. Pyrenyl aggregates which show structured fluorescence characteristics of the deposited film were formed on the layer containing excimer sites. A film of deposition stage which shows only the excimer fluorescence showed no fluorescence spectral change in vacuum even after 6 hours. However, when N2 gas was introduced into the chamber after deposition, the spectral change from the excimer to the structured fluorescence was observed slightly. Laser-assisted deposition induced the different aggregate structure of pyrenyl chromophores from that of the normally deposited film. The in situ fluorescence spectroscopy for vacuum deposition was found to be one of the powerful methods for elucidating the formation process of organic deposited films.
