One-Order Decreased Lattice Thermal Conductivity of SnSe Crystals by the Introduction of Nanometer SnSe₂ Secondary Phase

Abstract

In recent years, the layered semiconductor tin selenide (SnSe) has been of great interest in the thermoelectric field because of its remarkable thermoelectric potential. Here, the as-grown Sn 0.98 Se crystal was found to induce a random secondary phase of SnSe 2 in the host SnSe crystal due to similar formation enthalpy between SnSe and SnSe 2 . In addition, we carefully studied the thermal transport properties of as-grown Sn 0.98 Se crystals and intrinsic SnSe crystals. The Umklapp scattering is the prominent scattering and results in a low thermal conductivity of 0.77 W/m/K at room temperature along a direction in the intrinsic stoichiometry SnSe crystal. Because of the optical phonon contribution suppressed by the nanoscopic SnSe 2 intercalations in the as-grown Sn 0.98 Se crystal, the thermal conductivity further decreased to 0.45 W/m/K in nonstoichiometric as-grown Sn 0.98 Se crystals, which is a two-fold reduction and close to that of amorphous compounds. Our study may shed more light on the origin of the extra low thermal conductivity in as-grown Sn 0.98 Se crystals and may provide an efficient way to modulate thermal conductivity by microstructure engineering.

Thickness dependent thermal performance of a poly(3,4-ethylenedioxythiophene) thin film synthesized via an electrochemical approach

“…A schematic diagram of our system is shown in Fig. 2a and the detailed information of TDTR instrument [29][30][31] is presented in ESI. †…”

Temperature-Dependent n–p–n Switching and Highly Selective Room-Temperature n-SnSe2/p-SnO/n-SnSe Heterojunction-Based NO2 Gas Sensor

“…A strong peak at 184.9 cm −1 may be assigned to the A 1g mode of SnSe 2 . 35 Atom displacements in A g 1 , B 3g , and A g 3 modes are mostly out of the plane, whereas B 3g is an in-plane vibration mode. 35 A g 1 mode is also a shear mode that shifts atoms out of the plane along the a-axis.…”

“…35 Atom displacements in A g 1 , B 3g , and A g 3 modes are mostly out of the plane, whereas B 3g is an in-plane vibration mode. 35 A g 1 mode is also a shear mode that shifts atoms out of the plane along the a-axis. 34 Another two peaks at 114.7 and 253.3 cm −1 , have also been identified, corresponding to the B 1g 36 and E u vibration modes of the SnO phase.…”

“…In IR modes, the Sn sublattice is displaced with respect to O sublattice, resulting in a dipole moment in the molecule perpendicular to the c-axis. 37 The peak broadening indicates the transition from SnSe to SnSe 2 35 and the SnO phase. 36 Furthermore, the uniformly distributed ricelike nanostructures (∼180 nm length, ∼50 nm diameter) of SnSe 2 /SnO/SnSe heterojunction thin film were observed using a scanning electron microscope (SEM), as shown in Figure 2c.…”

Data-Driven Enhancement of ZT in SnSe-Based Thermoelectric Systems

“…Given the intrinsically beneficial electronic and phonon band structures of SnSe, proper doping can advantageously manipulate these structures and promise even higher TE performance outcomes. − Specifically, harnessing additional species is critical to improving the TE properties of a polycrystalline sample, which is the preferred form for broad practical applications of TE materials . Thus far, intensive studies have followed, including research on various single dopants − and examples of multielemental incorporation for co-optimizing the inherent transport properties and carrier concentrations. − As a result, several optimal cases showed highly enhanced TE performance capabilities. In particular, a ZT max value approaching 2.5 was realized in hole-doped and lead (Pb)-doped polycrystalline samples at 773 K after removing surface tin oxides, a result comparable to that of single-crystal SnSe .…”