PHOTOGENERATION OF CHARGE CARRIERS IN TETRACENE,
Abstract
The photocurrent and photovoltage of tetracene single crystals with aqueous electrodes were studied as a function of the excitation wavelength in the 220-560 millimicron region. The fluorescence efficiency of these crystals was studied in the same wavelength region. At wavelengths longer than 410 millimicron the photocurrent is due to injection of holes at the illuminated electrode. A bulk generated (electron) photocurrent is shown to be produced with excitation energies in excess of 3 eV, i.e. at wavelengths less than 410 millimicrons. The relative fluorescence efficiency begins to decrease with decreasing wavelengths at 410 millimicrons. The drop in fluorescence efficiency at excitation energies greater than 3 eV is attributed to the appearance of a non-radiative competitive process. The wavelength dependence of the bulk generated negative photocurrent is related to varying probabilities of transition from the different excited electronic states of the crystal to ionized states. The wavelength dependence of the photovoltage is strongly dependent on the negative charge density and exhibits minima in wavelength regions where this density is highest.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 25, 1966
- Accession Number
- AD0634905
Entities
People
- Hermit Kallmann
- Martin Pope
- Nicholas Geacintov
Organizations
- New York University