Ferroelectric photovoltaic characteristics of pulsed laser deposited 0.5Ba (Zr0.2Ti0.8)O-3-0.5(Ba0.7Ca0.3)TiO3/ZnO heterostructures

In this work, we investigate the photovoltaic response of Pt/0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3(0.5BZT-0.5BCT)/ITO structures through the insertion of a semiconductor ZnO layer at different positions. The values of short-circuit photocurrent density (Jsc) of the Pt/ZnO/0.5BZT-0.5BCT/ITO, Pt/0.5BZT-0.5BCT/ZnO/ITO and Pt/ZnO/0.5BZT-0.5BCT/ZnO/ITO capacitors are around 5.31, 0.0034 and 0.052 mA/cm2, respectively. The enhanced photovoltaic (PV) effect is observed when ZnO layer is inserted between Pt and the 0.5BZT-0.5BCT layer. The built-in field developed at the ZnO/ferroelectric interface in the same direction of the depolarizing field, provides a favorable electric potential for the efficient separation and transportation of photo generated e-h pairs. Furthermore, the polarization-dependent interfacial coupling effect enhances PV effect, which is confirmed by investigating the role of polarization flipping on switchable photo response. This work provides an efficient pathway in tuning the PV response in ferroelectric-based solar cells.This work was supported by: (i) Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2013 and (ii) Project Norte-070124-FEDER-000070 Nanomateriais Multifuncionais. Part of this work was supported by the COST Action MP1406 “Multiscale in modelling and validation for solar photovoltaics (MultiscaleSolar)”. The authors acknowledge the CERIC-ERIC Consortium for access to experimental facilities and financial support under proposal 20157018. The author J.P.B.S. is grateful for financial support through the FCT Grant SFRH/BPD/92896/2013. The author K.C.S. acknowledge UGC and DST-SERB, Govt. of India for the funds through the grant No.F.4-5(59-FRP/2014(BSR)) and ECR/2017/000068 respectively. The authors R.F.N., A.C.K. and C.G. acknowledge the financial support from Romanian Ministry of Research and Innovation in the frame of the Core Program PN18-11. The authors would also like to acknowledge P. B. Tavares, from Centro de Química da Universidade de Trás-os-Montes e Alto Douro, for the supply of the 0.5BZT-0.5BCT PLD target and Engineer José Santos for technical support at Thin Films Laboratory.