A piezoelectric current response to small applied mechanical pressure changes of lithium sulfate monohydrate nano-crystals

A piezoelectric current response to small applied mechanical pressure changes, as low as 1 Pa, in environmental 1 atm pressure conditions, is reported for Lithium Sulfate monohydrate (LSM) nano-crystals grown inside alumina pores. A higher piezoelectric sensitivity is obtained in crystals having a lower residual strain explained by a mechanical spring behavior. The crystals are grown by an isothermal precipitation process from over-saturated aqueous solutions only inside the pores. The crystals are grown with a preferred crystallographic orientation along the longitudinal axis of the pores, indicating a preferred nucleation at the bottom of the pores due to a lower surface energy and negative electric charges embedded in the alumina pore's walls. The nucleation and growth of the LSM crystals inside the pores is described with schematic drawings of the atoms arrival and arrangement in the unit-cell.