Effects of oxygen, nitrogen dioxide and trifluoroborane on photoconductivity of perylene and phthalocyanine single crystals

摘要: Exposure of single crystals zinc and lead phthalocyanine to low pressures (1–10 Pa) NO2 BF3 enhances the photoconduction by factors ca. 100 10, respectively, action spectra change resemble absorption spectrum, rather than its inverse as in vacuo. In air, similar changes spectra, but smaller magnitude, occur. Additional slow increases for air are consistent with oxygen diffusing into crystals. Photocurrent is proportional (light intensity)n, n= 0.54–0.62 vacuo, 0.34–0.40 0.20–0.27 NO2. Charge carrier generation mechanisms involving exciton dissociation at surface sites occupied adsorbed gas molecules discussed. Singlet perylene inhibited BF3, spectroscopic evidence presented reaction layers perylene, forming nitroperylene. A new response higher (103 Pa), centred 16 200 cm–1, following excitation a perylene–NO2 charge-transfer complex. This reversible on evacuation magnitude vacuum photoconduction.The different behaviours phthalocyanines discussed terms greater mobility electronic energy phthalocyanines. Photoconduction, although more sensitive concentrations semiconduction, has less potential detection due poor reversibility effects.