Dr. Xinglong RenDr. Xinglong Ren
08/04/2025
GTIIT: Room – E501, Education Building, North Campus \ ZOOM
17:00 - Jerusalem time / 12:00 - Beijing time
Despite their emerging applications in fields such as thermoelectrics, neuromorphic computing, and bioelectronics, fundamental aspects of charge transport physics in organic and hybrid conductors remain poorly understood. The unique structural features of organic materials make most existing theories developed for inorganics inapplicable. In the first part of this talk I will present how we currently understand the charge transport physics of organic semiconductors in an interesting regime known as transient localization. Organic materials are characterized by weak intermolecular van der Waals bonding, with soft vibrational modes and electronic processes occurring in a strongly fluctuating structural landscape. This gives rise to a distinctive transport regime where electronic excitations are effectively able to “surf” on the waves of molecular lattice distortion. The transient localization framework, which describes this behaviour, has been va
lidated by our experimental investigations on charge transport and spin relaxation in the benchmark organic semiconductor rubrene.
In the second part of the talk, I will talk about how to effectively control the electronic properties of organic and hybrid conductors, focusing primarily on the use of an electrolyte-gated transistor (EGT) platform. EGTs offer two key advantages: the ability to tune the carrier concentration over a wide range and the ease of integration into devices. This versatile platform allows for the realization of fundamentally intriguing phenomena, including metal-insulator transitions, carrier polarity switching, and access to deeper-lying HOMO-1 bands. Moreover, at ultrahigh charge densities, the interplay of many-body interactions (electron-ion and electron-electron correlations), gives rise to exotic, non-equilibrium transport features that provide unique insights into the interaction-driven formation of a frozen Coulomb gap in the density of states. Our work identifies potentially promising strategies for substantially enhancing transport properties of organic and hybrid conductors.