Elucidation of Charge Transport and Optical Parameters in the Newly 1CR-dppm Organic Crystalline Semiconductors

Abstract

As a part of a wide plan concerning the novel organic materials, a set of newly organic semiconductors has been obtained in our laboratories. In this paper, a clear overview was reported for elucidating the preparation processes of the chromium−copper mixed crystals. In line with the novel pyrazole diphenylphosphino-methane (M-dppm) derivatives, two mixed organic semiconductors were obtained: the one cupper apyrazole ring compound 5a, C 78 H 74 CrCuN 4 O 3 P 4 (1CR-dppm) and the two cupper apyrazole ring compound 6a, C 78 H 74 CrCu 2 N 4 O 4 P 4 (2CR-dppm). The structure of the obtained crystals were examined by the X−ray diffraction, and the structures of the two mentioned compounds were discussed based on elemental analysis (EA), IR, 1 H NMR, 31 P NMR spectroscopic data, and fast atom bombardment mass spectra. The compounds under investigation show typical semiconductor behavior due to of delocalization of the π-electrons in the structure. The temperature dependence of charge transports and optical parameters for the 5a crystals (C 78 H 74 CrCuN 4 O 3 P 4 ) were investigated and discussed in this work. This study was carried out with the aids of the transmittance and reflectance spectra in the temperature range 77−300 K. The reflectance and transmittance spectra were measured for the 5a organic crystalline semiconductors over the incident photon energy range 1.3−2.5 eV. These spectra were used for determining the optical parameters and elucidating the charge transport in the 5a compound.