Porous Materials for Thermoelectrics (John Anderson, Guilia Galli)
We propose to engineer MOFs with novel thermoelectric properties arising from specific combinations of electronic and magnetic couplings between ligands through a combined experimental and theoretical strategy, encompassing both the synthesis of new MOF frameworks and first principles calculations. Recently, there has been a great deal of focus on the discovery of conducting MOF materials and some reports of their thermoelectric properties. While increased conductivity results in enhanced classical Seebeck effects, the inclusion of magnetic interactions in these materials may also allow for Spin Seebeck effects.
MOFs are highly crystalline solids typically featuring organic ligands linking inorganic atoms or clusters in a 3-dimensional structure. The tunable nature of these materials makes them unique scaffolds for testing theoretical models for the realization of Spin Seebeck effects. The long organic linkers used to engender porosity, however, may also lead to poor orbital overlap between nodes, mitigating both magnetic and electronic coupling. One particular strategy to circumvent these issues is the installation of redox active motifs into the framework. Such incorporation fundamentally changes the electron transfer and magnetic coupling properties of these materials and appears to be a promising strategy to engineer strong coupling in porous systems.
Nanoscale Cellular Thermostats (Yamuna Krishnan, Bozhi Tian)
While non-equilibrium mechanics and chemical gradients have been utilized for active material design, there is still a need to introduce new components such as temperature variations with high spatiotemporal resolution. Complex living systems in fact exploit subtle temperature variations for biogenesis of diverse components. Although the average physiological temperature is 37°C, despite being part of the same circulatory system it is well known that specific organs are maintained at different temperatures for biogenesis e.g., lower temperatures are needed for spermatogenesis. There is also no information on whether temperature heterogeneity exists within a living cell. We propose to realise a technology to be able to spatially map temperature of a mammalian cell, generating a literal "heat map". In order to study the effect of temperature on fundamental, active processes within cells, we will leverage this technology to reversibly switch, at will, a specific patch of a live cell between a designated temperature and its physiological temperature. We propose proof of concept, by demonstrating this on the plasma membrane of a live cell.
Multifunctional Interfaces of different dimensionality (Timothy Berkelbach, Greg Engel, Giulia Galli, Philippe Guyot-Sionnest, Jiwoong Park, Steven Sibener, Dmitri Talapin, Luping Yu)
The bottom-up engineering of materials and devices has seen tremendous development in the last decade, promising more functional, low-cost, large- area, flexible, and printable electronic and optoelectronic devices, to meet the demand as new applications emerge and electronics becomes increasingly pervasive. However, the switch from materials that are bulk single crystals to assemblies of many components introduces new challenges, most notably the increased role of interfaces. Interfaces often introduce bottlenecks to charge transport and recombination sites that reduce carrier lifetime, and therefore typically yield lower performance devices. The dimensionality of the interface also differs from electronic dimensionality of the material. These are modified depending on the topology and quantum nature of the interfaces, as well as the role of defects.
This seed seeks to reveal fundamental connections between material and interface dimensionality and to develop new ways to rationally impact materials properties through interface engineering. We propose to investigate how interfaces affect the transport properties of materials with different dimensionality. Specifically, we will focus on transport of spin, charge, energy in form of excitons or plasmons and heat in form of phonons. Rationally designed interfaces will help us to understand the coupling between these fundamental degrees of freedom and excitations.