The polarizability of exciton and biexciton in polymer(analytical calculation)

Since the electroluminescence in polymer comes from the transportation and combination of carriers in the electric field,it is essential to study the polarization property of the excitation in polymer. First we obtain the ana lytic solutions of exciton and biexciton,then their polarizabilities are ca lculated using the Green function method. An important result is that we an alytically proved that the polarizability of the exciton is positive and th at of the biexciton is negative. It follows that the polarization will be r eversed when the exciton becomes biexciton.