Theory of Stark shifts in quantum wells consisting of highly anisotropic molecular-crystalline layers

We introduce a simple model to calculate the Stark shift in multiple quantum wells consisting of highly anisotropic and optically nonlinear molecular-crystalline layers. This model is used to calculate the exciton absorption peak in quantum-well structures consisting of the archetype planar molecular compounds; 3,4,9,10-perylenetetracarboxylic dianhydride, 3,4,7,8-naphthalenetetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic-bis-benzimidazole, and copper phthalocyanine. We find that the exciton absorption peak shifts by 60 to 70 meV in an electric field of <${10}^6$ V/cm. We also find that both redshifts and blueshifts are achieved for asymmetrical quantum-well structures.