(4w) Controlled Nucleation and Crystal Growth for Pharmaceutical, Electronic and Energy Applications

Molecular self-assembly processes, such as nucleation, crystal growth, aggregation, nano-/micro- phase separation, have a profound impact on the solid-state properties of materials. For instances, difference in crystal packing (polymorphism) influences bioavailability, stability and processibility of pharmaceutical compounds; morphology, molecular packing and orientation of organic semiconductors are critical in determining their charge transport characteristics; controlling the nanoscopic phase separation is key to achieving high-efficiency organic solar cells.

Solution printing offers great potential for achieving high-throughput, low-cost, large-area manufacturing of electronic and energy materials. However, rapid coating speed needed for industrial-scale production poses challenges to the control of molecular assembly during printing. Fluid-enhanced crystal engineering (FLUENCE)— a novel approach developed in my work, allows for a high degree of morphological control of solution-printed thin films, enabling record-setting material performances.

Interfaces play a pivotal role in directing the molecular assembly events. By engineering the nano-topology, microstructure and chemical patterns of surfaces and interfaces, my research has established new methodologies and demonstrated unprecedented control over nucleation kinetics, polymorphism and crystal morphology.  

Understanding the crystallization dynamics is key to devising design principles for controlling molecular packing and crystal morphology. Towards this end, my research utilizes powerful in situ synchrotron X-ray scattering techniques for investigating phase transformations and crystal growth kinetics during solution coating of organic semiconductor thin films.

With the new physical insight obtained and the novel approaches developed, I aspire to carry this research further towards 1) developing new technology platforms for fabricating next-generation pharmaceutical and energy materials, 2) deciphering the mechanism of molecular assembly processes at interfaces.