Energy and charge transfer from guest to host in doped organic electroluminescent devices

The luminescence properties of doped organic electroluminescent devices are explained by means of a Hamiltonian model. The results show that there is a corresponding relation between the amount of transferred charge and the change of the energy originating from charge transfer, and the relation can be influenced by dopant concentration. As the amount of transferred charge increases, the total energy decreases and the luminescence intensity increases. Therefore, we deduce that the energy transfer from guest to host may be derived from the charge transfer. For a given organic electroluminescent device, the maximum value of the conductivity can be observed in a specific dopant concentration. The calculated results show that the greater the transferred charges, the higher the conductivities in doped organic electroluminescent devices. The results agree basically with experimental results.