Amnon G. Ortoll-Bloch

Areas of Expertise

Previous Research

I am a materials chemist interested in crystal growth from solution. Crystallization from solution is a ubiquitous process that underlies a variety of biological and geological processes and is vital industrially and technologically. I am fascinated by the interplay between solution chemistry and crystallization pathways. For my Ph.D. research, I used in situ techniques to probe the crystal growth mechanisms of hybrid lead halide perovskites, materials that have attracted much attention for use in inexpensive, high-performance solar cells. Understanding how these materials grow can provide control over the morphology and properties of the resulting crystals and crystalline thin films. My work focused on establishing relationships between solution speciation and crystallization pathways. For example, we found that the coordinating ability of the solvent determines the crystallization pathway. Using a weakly coordinating solvent leads to a two-step pathway, where a crystalline intermediate forms first and then transforms to the final perovskite phase with heating. In contrast, strongly coordinating solvents can suppress the formation of these crystalline intermediates and promote the formation of the perosvkite directly from solution.

 

Current Research

My current research at Williams focuses on understanding and controlling the crystallization pathways of hydrothermally-grown cerium oxide nanocrystals. Ceria is a promising material for environmental remediation, as it can be used for the removal of toxic organic contaminants, such as textile dyes, from water by promoting photocatalytic oxidation reactions. By understanding how ceria nanocrystals form and grow from solution, we can optimize synthetic conditions to obtain materials with improved photocatalytic performance.