Direct Electron–Hole Recombination in Anthracene

Temperature studies of the recombination coefficient of holes and electrons in anthracene have been made. There was no significant change in the recombination coefficient in the temperature range room temperature to 130°C other than that predicted by the Thomson or the Langevin theories of recombination. Kinetic analysis shows that the recombination center (thought to be the charge‐transfer state) must have a binding energy $E_1{\mathrm{\hspace{0.17em}-\hspace{0.17em}E}}_{\mathrm{CT}}$ and a lifetime ${\beta }^{\text{−1}}$ such that $E_1{\mathrm{\hspace{0.17em}-\hspace{0.17em}E}}_{\mathrm{CT}}\text{\hspace{0.17em}>\hspace{0.17em}0.033}\mathrm{eV\; ln}{\text{(10R}}_m{N}_c\mathrm{\hspace{0.17em}/\hspace{0.17em}\beta )}$ , where $R_m$ is the measured recombination coefficient and $N_c$ is the density of states in the lower conduction band.