Flexible multiferroic heterostructures are promising to unveil technological developments in wearable magnetic field sensing, nonvolatile memory, soft robotics, and portable energy harvesters. Here, we report an enhanced and a zero-biased magnetoelectric (ME) effect in flexible, cost-effective, and room temperature sensitive Ni/FSMA/PMN-PT magnetization-graded ME heterostructure. Flexible Ni foil with −q (piezomagnetic coefficient) and the ferromagnetic shape memory alloy (FSMA; Ni-Mn-In) layer with +q offers the desired q-grading. The temperature-dependent dielectric behavior shows an anomaly in the martensite transformation regime of the FSMA layer. The Ni/FSMA/PMN-PT ME heterostructure exhibits noteworthy ME output of ∼3.7 V/cm Oe, significantly higher than Ni/PMN-PT (∼1 V/cm Oe). The q-grading-induced bending moment impedes the asymmetry-related flexural strain and strengthens the ME interaction. The zero-bias ME output of ∼0.4 V/cm Oe is ascribed to the interaction between q-grading-induced transverse magnetization and AC magnetic field. Ni/Ni-Mn-In/PMN-PT ME heterostructure displays excellent magnetic field sensing parameters: correlation coefficient, sensitivity, inaccuracy, and hysteresis of 0.99916, ∼0.74 mV/Oe, 1.5% full-scale output (FSO), and 1.8% FSO, respectively. The reversible and repeatable nonvolatile switching of the ME coefficient obtained with positive and negative electric fields is useful for next-generation memory devices. The flexible ME heterostructure shows no degradation in performance up to 1500 bending cycles. Such Ni/FSMA/PMN-PT based ME heterostructures are propitious for multifunctional flexible magnetic field sensors and nonvolatile memory applications.

The sustenance of the growing Internet of Things revolution requires suitable self‐powering solutions, which can be appropriately complemented by developing efficient energy harvesting systems. Typically, conventional piezoelectric thin film‐based energy harvesters are not promising due to high cost, low coverage area, and size‐frequency‐power trade‐off. Piezoelectric/triboelectric transduction driven mechanical energy harvesters (MEHs) based on nanocomposites offer better efficiency, cost‐effectiveness, and large‐scale production. Here, % weight ratio‐dependent piezoelectric/triboelectric property analysis, and optimization of Barium Titanate (BTO)/SU‐8 based photopatternable nanocomposite thin films are reported for developing highly efficient MEHs. Further, the performance of the nanocomposite is shown to be enhanced by controlled graphene nano‐platelet doping and ultraviolet (UV) exposure. Elaborate Finite Element Method (FEM) study is performed to support the experimental findings. Finally, three MEH devices are developed based on the optimally prepared variants of the nanocomposite and compared experimentally. A maximum output voltage of ≈3 V and power density of 0.65 µW cm−2 are obtained at 0.75 g and at the resonance frequency of 38 Hz from the graphene doped 20% BTO/SU‐8 based harvester. The prototypes have demonstrated the potential to deliver a regulated output voltage of 3.3 V within 40 s of periodic excitation upon integration with a customized power management unit for powering low‐power electronics.

The photo-induced triboelectric nanogenerator (PTENG) has been explored as new generation energy technology, which is enabled by coupling triboelectric and photo-induced charge carriers. PTENG shows a dual work mechanism that is attributed to the synergetic outcome of the photovoltaic and triboelectric effects. This study aims to provide a new strategy for triboelectric nanogenerator devices to achieve high output performance for various smart electronic device applications. Aluminum and n-type silicon were chosen as two different materials for triboelectric measurements. Different techniques were adopted to obtain triboelectric output parameters through the in-house developed triboelectric setup. AFM and Kelvin probe force microscopy imaging techniques were employed to obtain surface roughness and to measure the change in surface potential under the illumination of red (630 nm) laser light. A significant improvement in surface potential of around 40 mV was observed under laser illumination. Triboelectric characterization has been performed to obtain open circuit voltage (VOC) and short circuit current (ISC) with and without light illumination at different speeds of the motor. VOC and Isc were found to be 0.8 V and 2.2 nA, respectively, at 50 rpm speed without any illumination, which was further enhanced to 1.8 V and 5.5 nA, respectively, under the influence of laser light illumination. An increase in the motor speed to 100 rpm results in higher VOC (2.4 V) and higher ISC (3.4 nA) as compared to 50 rpm at no illuminating condition. However, it enhances to 3.4 V and 6.0 nA in illuminating conditions. This is attributed to the generation of charge carrier due to triboelectrification, which is further enhanced because of the photovoltaic effect wherein the generation of electron-hole pair occurs due to the shining of light on the side of semiconductors. These synergetic effects have tremendous potential in sustainable energy harvesting.