Nanomaterials, small particles consisting of only several thousand atoms and of only a few billionths of a meter in diameter, offer many opportunities for transformative science and technological applications. However, the lack of atomic precision during fabrication of nanometer-sized crystals restricts the ability to harness all the power of this broad and diverse class of materials. For example, a collection of real nanoparticles is always non-uniform and comprises particles with some variation in size within the group. Dr. Talapin is investigating how to eliminate this size variation and enable atomic precision in synthesis of nanoscale materials. Many practical applications, from flat-panel televisions to photodetectors and solar cells, will benefit from highly uniform, nearly atomically precise nanomaterials. Dr. Talapin is developing a technique called colloidal atomic layer deposition (c-ALD) to control the solution-based synthesis of nanomaterials using a sequence of two complementary self-limiting surface reactions. This concept is inspired by the success of gas-phase atomic layer deposition (ALD), which is widely used in microelectronics and other fields. Dr. Talapin's research has broader societal impact since it is directly relevant to the development of new technologically-relevant materials and has the potential to solve a fundamental problem that limits the pace of development for this broad class of materials. Dr. Talapin mentors undergraduate and high school students by helping them gain research experience. An important aspect of his outreach program focuses on education enrichment via science clubs and science nights for the local underrepresented African-American and Hispanic K-12 populations on Chicago's South Side. This project also supports the development and distribution of nanoscience educational resources accessible to the general public on the Talapin Lab website at the University of Chicago.
Dr. Talapin of the University of Chicago is supported by the Supramolecular and Nanochemistry (MSN) Program to develop colloidal atomic layer deposition (c-ALD) of nanoscaled materials with precise size dispersion. The project aims to eliminate inhomogeneous ensemble broadening by growing functional nanomaterials in a layer-by-layer fashion, starting from atomically defined clusters of different technologically important materials. The polydispersity of nanomaterials originates from a weak size dependence of the free energy related to the addition or removal of individual atoms to/from a nanoscale object. In this case, size distribution can only be controlled by kinetic factors. Both theoretical modeling and numerous experimental studies show that it would be difficult to improve homogeneity significantly by only kinetically controlling reaction products. Dr. Talapin is working on a paradigm-shifting approach for colloidal synthesis of nanomaterials with minimal, ideally no, size distribution. The goal is to establish means to thermodynamically control nanomaterials synthesis using a sequence of two complementary self-limiting surface reactions. This concept is inspired by the success of gas-phase atomic layer deposition (ALD) widely used in microelectronics and other fields. Preliminary studies show that the ALD concept can be implemented in solution and, when applied to colloidal nanomaterials, enables layer-by-layer growth of crystalline lattices with close to atomic precision. Eliminating polydispersity at the ensemble level is arguably one of the most important challenges in nanomaterial synthesis. One can draw an analogy between size distribution of nanomaterials and the polydispersity index (PDI) of polymers. The discovery of advanced living polymerization techniques, which nearly eliminate chain polydispersity, has been among the most important recent developments in macromolecular chemistry. Dr. Talapin incorporates activities with broader societal impact into his research program. He actively trains undergraduate and high school students in his lab by giving them research experience opportunities. He also develops course modules and nanoscience educational resources applicable to K-12 students which are accessible to the general public on the Talapin Lab website at the University of Chicago. These hands-on labs and experiments are also used in outreach and education enrichment events for the local underrepresented African-American and Hispanic K-12 populations in on Chicago's South Side.
