ISSN:
1433-0768
Keywords:
Key words Polybithienyl
;
Organic semiconductor
;
Photocurrent
;
Gaertner-Butler model
;
Band gap energy
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract Photoelectrochemical measurements have been performed at a polybithienyl (PBT) film (doping level of 1 × 1018/cm3) deposited on a platinum electrode. The cathodic photocurrents and negative slope of the Mott-Schottky plot indicate that the PBT film has the features of a p-type semiconductor. The cathodic photocurrents are interpreted in terms of the Gaertner-Butler model on the basis of the theory of the semiconductor|solution interface. The (i ph hν)2/n vs. hν plots taken from the photocurrent spectra show two linearities for n=1 in the wavelength range from 460 nm to 490 nm and for n=4 in the wavelength range λ 〉 490 nm. The band gaps of the PBT film were determined to be 2.05 ± 0.05 eV for n=1 and 1.55 ± 0.05 eV for n=4. The flat-band potential is 0.33 V (vs SCE). From the slope of the Mott-Schottky plot at the modulation frequency of 3 kHz, the dielectric constant ɛ of the film and the thickness of the depletion layer W 0 of the PBT film were determined to be 7.4 and 0.29 μm, respectively.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s100080050199
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