Dark Injection and Radiative Recombination of Electrons and Holes in Naphthalene Crystals

Abstract

Negative carriers have been injected into naphthalene crystals from a contact consisting of the sodium–potassium eutectic which is liquid at room temperature. The voltage dependence of the space-charge-limited (scl) current is determined by an exponential distribution of traps in energy. Positive carriers were injected into naphthalene crystals from the redox systems Ag2+/Ag+ in 7.5N HNO3 and Ce4+/Ce3+ in 15N H2SO4 leading for the first system to a space-charge-limited current and in the second one to a current–voltage curve which is determined by a field assisted hole injection reaction. Double injection of electrons and holes leads to radiative recombination under emission of the naphthalene fluorescence spectrum.