Optical and photoelectrical properties of the tetrathiotetracene- fullerene (TTTC60) film heterostructures

Abstract

The optical and photoelectrical properties of heterostructures (HS) SnO 2 ТTTC 60 Ag are investigated. The additional absorption of HS ТTT and C 60 is revealed in comparison with those for their components, which testifies to the formation of complexes between the ТTT and C 60 molecules near the ТTT-C 60 interface. Currentvoltage characteristics (J-V) of a dark current is symmetric, as well as corresponds to the Ohm law for the voltages of 0 to 0.4 V. In the voltage range of 0.4 to 1.0 V, the branch of J-V at the positive polarity (I +) goes above that at the negative polarity (I −) at a SnO 2electrode. Thus, in the double logarithmic scale, I + and I − are described by direct lines with the angular factors 1.77 and 1.37, accordingly, and exponents in the half-logarithmic coordinates (log I−U). The open-circuit voltage V oc has a positive polarity at the SnO 2electrode irrespective of the illumination direction of a sample. Photovoltage is caused by antiblocking bends of bands for holes and electrons near the SnO 2-and Ag-electrodes of ТTT and C 60 films, accordingly. The dark effective specific resistance of the HS SnO 2 ТTTC 60 Ag is equal to 5•10 7 Ohm•cm.

Structural, Optical, and Photovoltaic Properties of Tetracene Thin Films

“…Absorption spectra were registered on a Perkin Elmer Lambda 25 uv/vis spectrophotometer at a spectral width of 1 nm and at room temperature. The spectral dependences of the photo-emf were measured using the method of capacitor cell, which was described in work [20]. The structure of Tc films was studied using an optical microscope Carl Zeiss Pernal Interphako and an electron scanning microscope JSM-35 (IEOL, Japan).…”