Balanced Dipole Effects on Interfacial Engineering for Polymer/TiO₂ Array Hybrid Solar Cells

The polymer/TiO₂ array heterojunction interfacial characteristics can be tailored by balanced dipole effects through integration of TiO₂-quantum dots (QDs) and N719 at heterojunction interface, resulting in the tunable photovoltaic performance. The changes of V _oc with interfacial engineering originate from the shift of the conduction band (E _c) edge in the TiO₂ nanorod by the interfacial dipole with different directions (directed away or toward the TiO₂ nanorod). The J _sc improvement originates from the enhanced charge separation efficiency with an improved electronic coupling property and better charge transfer property. The balanced dipole effects caused by TiO₂-QDs and N719 modification on the device V _oc are confirmed by the changed built-in voltage V _bi and reverse saturation current density J _s.