Dielectric Mismatch Mediates Carrier Mobility in Organic-Intercalated
Layered TiS<sub>2</sub>
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Abstract
The dielectric constant is a key
parameter that determines both optical and electronic properties of
materials. It is desirable to tune electronic properties though dielectric
engineering approach. Here, we present a systematic approach to tune
carrier mobilities of hybrid inorganic/organic materials where layered
two-dimensional transition-metal dichalcogenide TiS<sub>2</sub> is
electrochemically intercalated with polar organic molecules. By manipulating
the dielectric mismatch using polar organic molecules with different
dielectric constants, ranging from 10 to 41, the electron mobility
of the TiS<sub>2</sub> layers was changed three times due to the dielectric
screening of the Coulomb-impurity scattering processes. Both the overall
thermal conductivity and the lattice thermal conductivity were also
found to decrease with an increasing dielectric mismatch. The enhanced
electrical mobility along with the decreased thermal conductivity
together gave rise to a significantly improved thermoelectric figure
of merit of the hybrid inorganic/organic materials at room temperature,
which might find applications in wearable electronics