Biomineralization of Quantum Confined Nanocrystals and Heterostructures for Electrochemical Applications

Abstract

Functional nanomaterials are at the core of many innovations in renewable energy generation and catalysis. However, many of these materials are currently synthesized through high temperature, multi-step processes that utilize organic solvents and expensive precursors. These factors increase the complexity and economic and environmental costs of manufacturing scale-up. In contrast, biomineralization, the process by which biological systems produce structural nanomaterials, occurs under ambient conditions in aqueous media utilizing readily available precursors. We have developed a novel single enzyme route for the direct, scalable and controlled synthesis of a variety of pure and hetero-structured metal chalcogenide quantum dots. This approach represents perhaps the simplest biosynthesis system for these materials, consisting of only the single enzyme, a metal precursor, and amino acid sulfur source, and capping agent in an ambient temperature, buffered, aqueous solution. However, tight control of the growth parameters yields size and composition controlled crystalline materials and heterostructures with functional properties comparable to materials synthesized by traditional chemical routes. We demonstrate the application of this approach to direct biomineralization of quantum dots within solar cell photoanodes, and in fully biomineralized quantum dot/reduced graphene oxide photocatalysts.