Free Charges and Excitons in Stilbene Single Crystals Excited by Electron Pulses

The kinetics of relaxation currents, light absorption, and luminescence after excitation of stilbene single crystals by a pulse of accelerated electrons with τ = 40 × 10 −9 s is measured. The excitation results in bulk generation of free charges and excitons. The microscopic mobilities are found to μ p = 2.2 cm 2 V −1 and μ, = 0.2 cm 2 V −1 s −1 . The radiation yield of the charges is G ( p, e ) = 0.25 ± 0.02, and of triplet excitons G ( T ) = 3.6. The optical absorption spectrum of triplet excitons is recorded, and it is found that v max = 2.22 × 10 4 cm −1 , the absorption coefficient K v max = 0.17 cm −1 , and the oscillator strength of the T 2 ← T 1 optical transition band f = 0.20. The probability of creation of charges .