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

Abstract

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 Voc with interfacial engineering originate from the shift of the conduction band (Ec) edge in the TiO2 nanorod by the interfacial dipole with different directions (directed away or toward the TiO2 nanorod). The Jsc 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 Voc are confirmed by the changed built-in voltage Vbi and reverse saturation current density Js.