Ferroelectrics are a class of materials that exhibit unique electronic behavior that has the potential to revolutionize energy storage and random-access memory design. Their polar, non-centrosymmetric crystal structure results in inherent piezoelectric and pyroelectric properties and can therefore be used for energy harvesting applications. CdSe nanocrystals are ubiquitous in nanoscience and, unlike their bulk counterparts, can be deposited through spin-coating, spray-coating, reel-to-reel printing, and ink-jet printing onto flexible substrates at low temperatures. In our studies, ferroelectric behavior arose through a room-temperature cation exchange of semiconductor nanoparticles. Because cadmium selenide and cadmium sulfide quantum dot syntheses have been thoroughly studied, cation exchange synthesis grants access to control over many precisely defined shapes, sizes, and compositions of ferroelectric nanoparticles. Additionally, synthesis of ferroelectric nanoparticles using cation exchange of highly studied quantum dots yields the possibility of improved stability of ferroelectric nanoparticles. Cation exchange reactions were performed on colloidal nanocrystals using metal chloride salts. The atomic percent of exchange cation was determined using STEM-EDS and ferroelectric properties were measured using a Sawyer-Tower circuit. Variation in exchange cation identity and atomic percent allows for control over ferroelectric properties. The ability to tune the structure and ferroelectric response of nanostructures offers a broad range of applications for these ferroelectric nanoparticles formed through a simple room-temperature cation exchange synthesis.

Modulating ferroelectric response in colloidal semiconductor nanocrystals through cation exchange

2019 Fall National Meeting

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