Research Projects

Top: Silverbromoiodide nanocrystals synthesized by colloidal nucleation & growth. Bottom: 3D nanostructured Se–Te films grown by electrochemical photopatterning

 The Sadtler research group is interested in how hierarchical structure of materials from the atomic level to nano- and micro-scale can be used to control their physical properties and chemical reactivity. Research projects in our group combine the chemical synthesis of inorganic materials and tailoring light-matter interactions at the nanoscale. We aim to develop functional materials for solar energy conversion, photonics, and catalysis. The members of our group have backgrounds in chemistry, materials science, and chemical engineering.

Solid-state chemistry of nanoscale materials: Chemical transformations are remarkably efficient in nanoscale materials owing to the high surface area and short diffusion lengths necessary to complete the transformation. We are interesting in using solid-state reactions to alter the composition of nanoscale materials while preserving their morphological features. This research aims to develop new combinations of nanocrystal shape and compositions that are useful for optoelectronic devices, such as light-emitting diodes and solar cells. 

Photocatalysis for fuel generation: The synthesis of chemical fuels from sunlight provides an effective way to store solar energy for use in transportation and to produce commodity chemicals. Semiconductor photocatalysts absorb solar photons and can use the resulting photoexcited charges to drive fuel-forming chemical reactions. Our group is interested in chemical transformations such as the photocatalytic oxidation of methane to methanol and the reduction of carbon dioxide to liquid products. The crystalline facets present at the surface of the semiconductor catalysts dictate the pathways and lifetimes of photogenerated charge carriers. We use colloidal synthesis and electrodeposition to make shape-controlled semiconductor crystals so that we can correlate their nanoscale morphology with photocatalytic activity. 

Material growth under external fields.  Chemists typically use external parameters such as temperature, pressure, and concentration to direct chemical transformations in molecules and materials. Many classes of materials are also responsive to external stimuli, such as light or electric and magnetic fields. We are creating adaptive inorganic materials that adjust their growth in response to externally controlled fields as a novel route to synthesize three-dimensional nanostructures. Stimuli-driven growth of complex structures can provide new material architectures with enhanced optoelectronic properties for applications in solar energy conversion and photonics.

Imaging structure and activity at the nanoscale: Inorganic particles produced by chemical synthesis exhibit a distribution in size and shape and possess different possible reaction sites. This heterogeneity makes it difficult to correlate specific morphological features with catalytic activity when measurements are made on large groups of particles. Single-molecule fluorescence microscopy provides the ability to resolve objects well below the optical diffraction limit (down to a few nanometers) by localizing the emission profile of individual fluorophores with high precision. We are applying single-molecule, super-resolution fluorescence microscopy to image the conversion of individual fluorogenic probes on the surface of shape-controlled photocatalyst particles. Through nanoscale localization of reaction events, this work aims to identify how different morphological features contribute to the overall activity for a dispersion of inorganic catalysts.