PHOTOCONDUCTIVITY AND ABSORPTION AND FLUORESCENCE SPECTRA OF 9,10-DICHLOROANTHRACENE

Abstract

The spectral response, voltage, light intensity, and temperature dependences of the photocurrent generated in crystals of 9,10-dichloroanthracene have been studied as well as the absorption and fluorescence spectra. The magnitude of the measured photocurrent was 102–103 times larger than that observed in anthracene under similar conditions. The spectral response of the photocurrent in the surface cell arrangement was found to depend on the direction of the incident light relative to the electrodes. Above a certain value of the applied voltage the photocurrent was found to be ohmic. The photocurrent increased as the 0.7 or 0.8 power of the light intensity depending on whether the light was incident on the same side or opposite sides of the crystal face containing the electrodes. When the crystal was cooled the photocurrent passed through a maximum between 20° and 0 °C.The absorption edge of crystalline 9,10-dichloroanthracene as well as the absorption spectrum in chloroform solution were determined. When the crystals were cooled the fluorescence spectrum was observed to shift to longer wavelengths and the intensity increased between two and three times.