Exploring piezoelectric and piezophototronic properties of nanostructured LN-ZnSnS3 for photoresponsive vibrational energy harvesting

Abstract

Piezoelectric energy harvesters have for some time been an advanced choice for self-powered electronics. While oxide-based piezoelectric nanomaterials are well studied for their quality mechanical energy harvesting potential, recent interest in developing multifunctional nanomaterials for harvesting simultaneous ferroelectric/piezoelectric and light energy for photodetectors, photovoltaics and piezophototronics has impelled the search for newer semiconducting dipolar materials. In this respect, LiNbO₃ type-ZnSnS₃ (LN-ZTS) is predicted to have low optical band gap energy and to possess a considerably expanded hexagonal R3c lattice with high ferroelectricity. Although it has been stabilised in thin-film form, the exclusive synthesis of LN-ZTS nanocrystals has not been reported. In this article, we report a one-step synthesis for R3c hexagonal LN-type ZnSnS₃ (ZTS) nanoflakes and show that they could be highly desirable candidates for light-responsive mechanical energy harvesting via an impressive piezophototronic effect. A piezoelectric coefficient (d₃₃) of ∼19 pm V⁻¹ was measured using piezoresponse force microscopy and a considerable zero-bias photoconduction current was observed, which was utilized to harvest an output power of ∼0.13 μW cm⁻² from an induced light intensity of 100 mW cm⁻² under a mechanical impact of 17 N and 3 Hz. These findings establish a previously unreported ternary sulfide piezoelectric nanostructured material as potential candidate for designing piezophototronic devices by coupling optical functionalities and piezoelectric responses.