Fig. 4: Bending-tunable photovoltaic properties of freestanding Pt/BFO/LSMO.
a J–V switching loops in dark of the freestanding photovoltaic cells with different bending status. b P–V loops of the flexible device as a function of the strain gradient. c J–V curves under light illumination for both polarizations (with light intensity of 20 mW/cm2) of the flexible devices with different bending radius. Red curves: polarization downward; blue curves: polarization upward. d The corresponding change of Voc and Jsc as function of the introduced in-plane strain gradient for both polarizations. e The change of the Voc and Jsc with the function of the introduced in-plane strain gradient (SG) after different bending cycles. The polarization of BFO is downward. f The experimental data of ΔVoc with both upward and downward polarization directions, and the fitted ΔVoc as the function of the strain gradient by using the value of 0.5 for scaling factor λ. SG1 to SG4 corresponds to the increasing strain gradients of four different bending radii in Fig. 1b. The purple and yellow arrows in c and e represent the downward and upward polarization of BFO. The error bars in f are calculated from multiple measurement results in e and Supplementary Fig. 10h.
