Improving the efficiency of organic photovoltaic cells by introducing an ultrathin modification layer with a strong dipole moment

【摘要】：A method to improve the efficiency of organic photovoltaic cells through inclusion of an ultrathin modification layer of Al2O3 or LiF sandwiched between poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid(PEDOT:PSS) and indium tin oxide layers is developed.Because of the strong dipole moments of LiF and Al2O3,either can enhance the built-in electric field,which increases the probability of the carriers reaching the corresponding electrode.In addition,the low work function of PEDOT:PSS can decrease the energy barrier for carrier transmission.A 21.7% improvement in the power conversion efficiency of experimental devices was achieved,mainly because the short circuit current was enhanced by almost 30%.