Transient photoresponses spectra measurement of ultrathin organic films by white light optical waveduide method

摘要

White light optical waveguide (WOWG) method was applied to transient absorption spectroscopy of ultrathin polymer and Langmuir-Blodgett (LB) films. Tetraphenylporphyrin in poly (vinyl alcohol) films and in a mixed LB films with arachidic acid were prepared on the surface of OWG glass. The WOWG method was sensitive more than 160 times than a conventional absorption method. These films were excited with the second harmonics of a Nd:YAG laser. The transient absorption spectrum of excited triplet tetraphenylporphyrin was detected highly sensitively for a film with the absorbance at excitation wavelength of only 0.0005 by the WOWG method.