Unveiling predominant air-stable organotin bromide perovskite towards mechanical energy harvesting.

The development of organotin halide perovskites is as an appropriate substitute to replace highly toxic lead-based hybrid perovskites, which are a major concern for the environment as well as for human health. However, instability of the lead-free Sn-based perovskites under ambient conditions has hindered their wider utility in device applications. In this study, we report a predominantly stable lead-free methylammonium tin bromide (MASnBr3) perovskite that has air-stability over 120 days without passivation under ambient conditions. Further, the feasibility of these predominant air-stable MASnBr3 perovskite for use in the harvesting of mechanical energy is described with the fabrication of an eco-friendly, flexible and cost-effective piezoelectric generator (PEG) using MASnBr3-polydimethylsiloxane composite films. The fabricated PEG exhibits high performance along with good mechanical durability and long-term stability. This flexible device reveals high piezoelectric output voltage of ~ 18.8 V, current density of ~ 13.76 µA/cm2, and power density of ~ 74.52 µW/cm2 under a periodic applied pressure of 0.5 MPa. Further, the ability of the PEG to scavenge energy from various easily accessible biomechanical movements is demonstrated. The energy generated from the PEG by fingers tapping is stored in a capacitor and is used to power both a stop-watch and a commercial light emitting diode (LED). These findings offer a new insight to achieve long-term air-stable Sn-based hybrid perovskite that demonstrates the feasibility of using organotin halide perovskites to realize highly-efficient, eco-friendly, mechanical energy harvesters with a wide range of utility that includes wearable and portable electronics as well as biomedical devices.