Strong excitonic effect in organic–inorganic hybrid crystals

We investigate the optical properties of the hybrid crystal ZnTe(C2H8N2)0.5 from first principles. The excitonic effect is included by solving the Bethe–Salpeter equation for the two-particle Greenʹs function. The inorganic ZnTe acts as optical active layer and the excitonic wave function is confined within it by C2H8N2 layers. Due to the confinement of electronic states, electron–hole interaction within ZnTe layers is enhanced and the absorption spectra are thus changed drastically. The exciton binding energies are 0.54 and 0.42 eV for α and β structures, respectively. The calculated quasiparticle gap of the β structure is 3.68 eV.