Photovoltaic Performance and Long-Term Stability of Hybrid ZnO/TiOPc Solar Cells with DH-α6T as an Electron Blocking Layer

Abstract

This article reports on photovoltaic performance and long-term stability of hybrid solar cells based on ZnO/TiOPc with DH-α6T as an electron blocking layer. When the thermal annealing temperature (TA) was increased from 120 °C to 180 °C, these absorption spectra of TiOPc thin films reveal the gradual formation of the crystalline α-phase, as evidenced by the development of a red-shifted absorption band, peaking 845 nm, and the corresponding reduction of the 720 nm amorphous phase peak. Device performance of hybrid solar cells could be improved and open-circuit voltage (VOC), short-circuit current (ISC) and power conversion efficiency (η) were enhanced by thermal annealing, which originated from amorphous TiOPc films transformed into crystalline α-TiOPc films with a wider red and near-IR absorption band. At TA= 150 °C, the device achieved the highest performance with VOC, ISCand η of 0.53 V, 1.71 mA/cm2, and 0.29 %, respectively. Furthermore, the hybrid device showed long-term stability that this device maintained over 55 % of its initial η after 300 days aging at room temperature.