Piezostrain-enhanced photovoltaic effects in BiFeO3/La0.7Sr0.3MnO3/PMN-PT heterostructures

BiFeO3 (BFO) is a unique multiferroic material that shows interesting but rather weak photovoltaic effect. Here, we report the integration of PUBFO/La0.7Sr0.3MnO3(LSMO) photovoltaic devices on piezoelectric 0.71Pb(Mg1/3Nb2/3)O-3-0.29PbTiO(3) (PMN-PT) single-crystal substrates and realized a piezo-photovoltaic effects in the BFO/LSMO/PMN-PT heterostructures through in situ dynamical strain engineering. Upon the application of an electric field of +10 kV/cm, an in-plane compressive strain was induced in the PMN-PT via the converse piezoelectric effect, which was effectively transferred to the BFO film through the LSMO, leading to a change in the in-plane strain and bandgap of the BFO film by similar to 0.12% and similar to 22 meV, respectively. As a result, the power conversion coefficiency (PCE) eta was dramatically enhanced by similar to 218%, corresponding to a gauge factor (Delta eta/eta)/delta(epsilon xx)similar to 1817. The results demonstrate that the dynamic strain engineering of photovoltaic properties using the converse piezoelectric effect is an effective and unique approach for realizing enhanced PCE of ferroelectric thin film based photovoltaic devices. (C) 2015 Elsevier Ltd. All rights reserved.