《ACS Appl. Mater. Interfaces》Prof Rupak Banerjee, IIT, India Tunability of halides improves the performance of lead-free Cs2SnX6-PVDF composites in biomechanical energy harvesting
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Prof. Rupak Banerjee of the Indian Institute of Technology Gandhinagar, along with his research team led by Tufan Paul, published a recent research article in ACS Applied Materials & Interfaces on July 13, 2023.
The primary objective of this study was to develop a lead-free organic-inorganic halide perovskite material for biomechanical energy harvesting and pressure sensing applications.
Traditional organic-inorganic halide perovskite materials, such as CH3NH3PbI3, exhibit excellent optoelectronic properties but suffer from poor long-term stability and lead contamination issues.
Therefore, the team explored Cs2SnX6 (X = Cl, Br, and I) compounds as an environmentally friendly and sustainable alternative. These compounds are lead-free and possess good environmental stability and optoelectronic performance.
Furthermore, they can be combined with the piezoelectric polymer polyvinylidene fluoride (PVDF) to create self-powered piezoelectric nanogenerators (PENGs).
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Prof. Rupak Banerjee’s team synthesized Cs2SnX6 nanostructures through a solvothermal method and mixed them with PVDF to produce composite films. They found that the addition of Cs2SnX6 enhanced the electrical activity phase in PVDF, thereby improving the piezoelectric performance of the composite films. First-principles density functional theory (DFT) calculations were also employed to analyze the interface interaction between Cs2SnX6 and PVDF, revealing a physical adsorption mechanism between the perovskite and PVDF, leading to enhanced piezoelectric response. The researchers systematically varied the halide ions in the inorganic Cs2SnX6 perovskite and studied the corresponding piezoelectric behavior of the PENGs. Additionally, they measured the dielectric properties, piezoelectric response amplitude, piezoelectric output signal, and charging capacity of these halide perovskite-based mixtures.
Among the various prepared films, the optimized Cs2SnI6_PVDF film exhibited the highest piezoelectric coefficient (d33) value of approximately 200 pm V–1, and a residual polarization of about 0.74 μC cm–2 was obtained from piezo-force microscopy and polarization hysteresis curve measurements. The optimized Cs2SnI6_PVDF-based device generated an instantaneous output voltage of around 167 V, a current of approximately 5.0 μA, and a power of about 835 μW when subjected to periodic vertical compression. The output voltage of the device was used to charge a 10 μF capacitor, which reached a voltage of 2.2 V and was able to drive some commercial LEDs. In addition to being used as a pressure sensor, the device was also employed to monitor human physiological activities. The device demonstrated excellent operational durability in the environment, showcasing its outstanding potential for mechanical energy harvesting and pressure sensing applications.
This research provides a new approach for developing lead-free halide perovskite materials and offers an effective method for utilizing biomechanical energy to drive wearable devices and self-powered systems. The research team expressed their intention to continue optimizing the performance of these materials and devices, as well as exploring further application scenarios.
Organic Photovoltaic Cells、OPV、Quantum Efficiency