SnSe Matrix Research Articles

Boosting thermoelectric performance of polycrystalline SnSe by controlled in-situ Ag2Se precipitates in grain boundaries

Boundary engineering has proven effective in enhancing the thermoelectric performance of materials. SnSe, known for its low thermal conductivity, has garnered significant interest; however, its application is hindered by poor electrical conductivity. Herein, the Ag8GeSe6 is introduced into the p-type polycrystalline SnSe matrix to optimize the thermoelectric performance, and the in-situ Ag2Se precipitates are formed in grain boundaries, which play dual roles, acting as an electron attraction center for improving hole concentration and a phonon scattering center for reducing lattice thermal conductivity. It effectively decouples the thermal and electrical transport properties to optimize the thermoelectric performance. Importantly, the amount of Ag2Se can be controlled by adjusting the amount of Ag8GeSe6 added to the SnSe matrix. The introduction of Ag8GeSe6 enhances electrical conductivity due to the increased hole carrier caused by the introduced Ag+ and the formed electron attraction center (in-situ Ag2Se precipitates). Based on the DFT calculations, the band gap of the Ag8GeSe6-doped samples is considerably decreased, facilitating carrier transport. As a result, the electrical transport properties increase to 808 μW m−1 K−2 at 823 K for SnSe + 0.5 wt% Ag8GeSe6. In addition, in-situ Ag2Se precipitates in grain boundaries strongly enhance phonon scattering, causing a decrease in lattice thermal conductivity. Furthermore, the presence of defects contributes to a reduction in lattice thermal conductivity. Specifically, the thermal conductivity of SnSe + 1.0 wt% Ag8GeSe6 decreases to 0.29 W m−1 K−1 at 823 K. Consequently, SnSe + 0.5 wt% Ag8GeSe6 obtains a high ZT value of 1.7 at 823 K and maintains a high average ZT value of 0.57 over the temperature range of 323−773 K. Additionally, the mechanical properties of Ag8GeSe6-doped also show an improvement. These advancements can be applied to energy supply applications during deep space exploration.

Enhancing thermoelectric performance of solution-processed polycrystalline SnSe with PbSe nanocrystals

There is a growing interest in cost-effective polycrystalline SnSe-based thermoelectric (TE) materials, which are able to replace the high performance but mechanically fragile and costly single-crystalline SnSe. In this study, we present a low-temperature solution-based approach to produce SnSe-PbSe nanocomposites with outstanding TE performance. Our method involves combining surfactant-free SnSe particles with oleate-capped PbSe nanocrystals in specific ratios, followed by thermal annealing and consolidation using spark plasma sintering. These nanocomposites are characterized by distinct compositional and structural properties that significantly impact their transport properties. In particular, the addition of oleate-capped PbSe nanocrystals results in: i) a reduction in the electrostatically adsorbed Na at the surface of the SnSe particles; ii) a reduction of Sn vacancies due to alloying with Pb; iii) an increase in grain boundary density; and iv) the formation of PbSnSe secondary phases. Notably, the SnSe-2.5 %PbSe nanocomposites demonstrate a 30 % decrease in thermal conductivity compared to that of the SnSe matrix. This reduction contributes to a maximum figure of merit (zT) of 1.75 at 788 K with a high average zT value of ca. 1.2 in the medium temperature range of 573–773 K. These values represent one of the highest reported in polycrystalline SnSe materials, showcasing the potential of our fabricated SnSe-PbSe nanocomposites for cost-effective TE applications.

Simultaneously Enhanced Thermoelectric and Mechanical Performance in SnSe-Based Nanocomposites Produced via Sintering SnSe and KCu7S4 Nanomaterials.

Both thermoelectric and mechanical properties are important to the practical applications of thermoelectric materials. Herein, we develop a strategy for alloying KCu7S4 to improve the dimensionless figure of merit (zT), compressive strength, and Vickers hardness of polycrystalline SnSe. Through chemical synthesis and particle mixing in solutions, powders with SnSe nanoparticles and KCu7S4 nanowires are produced, and the subsequent spark plasma sintering triggers the reaction between the two chalcogenides, resulting in the formation of Cu2SnSe3 nanoparticles and substitution of Cu and S in the SnSe matrix. The composition tuning and secondary phase formation effectively enhance the power factor and diminish the lattice thermal conductivity, leading to a maximum zT of 1.13 at 823 K for the optimal sample, which is improved by 135% over that of SnSe. Simultaneously, the compressive strength and hardness are also enhanced, as exemplified by a high compressive strength of 135 MPa that is enhanced by ∼81% compared to that of SnSe. The current study demonstrates effective composite and composition design toward enhanced thermoelectric and mechanical performance in polycrystalline SnSe.

P-type Sn0.98Ag0.02Se with low thermal conductivity synthesized by hydrothermal method

Tin selenide exhibits outstanding thermoelectric properties. Among its various forms, multicrystalline SnSe stands out as a more practical choice compared to single-crystal SnSe, owing to its straightforward chemical synthesis process, enhanced processability, and scalability. Herein, we synthesized p-type polycrystalline Sn1−xAgXSe bulk materials (x = 0, 0.01, 0.015, 0.02, 0.025, 0.03) using a simple hydrothermal and hot pressing method. Characterization methods such as XRD, Raman and XPS were used to demonstrate the successful doping of Ag+ into the SnSe matrix. When the doping concentration reached Sn0.98Ag0.02Se (x = 0.02), Ag+ reached the optimal concentration in the SnSe matrix, causing significant lattice distortion which increased phonon scattering and lowered the thermal conductivity, resulting in Sn0.98Ag0.02Se achieving ZTmax= 1.14. However, when the doping concentration exceeded Sn0.98Ag0.02Se (x > 0.02), excess silver ions precipitated, partially acting as charge carriers, leading to a significant increase in electrical conductivity, resulting in Sn0.97Ag0.03Se having an electrical conductivity of 6860 s/m at 773 K. Compared to the pure phase, the electrical conductivity of Sn0.97Ag0.03Se increased by 259 %, and the ZT value of Sn0.98Ag0.02Se increased by 178%. This work demonstrates that Ag+ is an effective p-type dopant in the SnSe system and indicates that high ZT values in SnSe can be achieved through a simple, low-cost, and environmentally friendly method.

Study on the Degradation of Methylene Blue by Cu-Doped SnSe.

Treatment of organic wastewater is still a difficult problem to solve. In this paper, Cu-doped SnSe powder was synthesized by a convenient and efficient hydrothermal method. Meanwhile, the degradation effect of different doping concentrations of SnSe on methylene blue was investigated. It was found that at low doping concentrations, the degradation effect on methylene blue was not obvious because Cu was dissolved in the lattice of the SnSe matrix at low concentrations. As the doping concentration increased, SnSe changed from a layered structure to a nanocluster structure with reduced particle size, and a mixed phase of SnSe and Cu2SnSe4 appeared. In fact, the degradation effect on methylene blue was significantly enhanced, and we found that the catalytic degradation effect on methylene blue was best at a doping concentration of 10 wt.%.

Enhancing the thermoelectric performance of solution-synthesized SnSe-based materials via incorporating Ti3C2Tx MXene

SnSe-based materials, comprising nontoxic, eco-friendly and abundant elements, have intrinsically low lattice thermal conductivity, which are promising candidates for thermoelectric conversion. However, unmodified, polycrystalline SnSe reveals poor electrical transport properties due to the lower carrier mobility. Herein, two-dimensional Ti3C2Tx MXene has been incorporated into SnSe matrix by solution synthesis and fast consolidation, which efficiently increases the carrier mobility and concentration; accordingly, the electrical conductivity is improved in the temperature range of 323–523 K. Meanwhile, SnSe/Ti3C2Tx composites achieve diminished lattice thermal conductivity, delivering a low value of 0.41 W m−1 K−1 at 773 K. Ultimately, a peak zT of 0.93 at 773 K is attained in SnSe/Ti3C2Tx composite with addition of 0.3 wt% Ti3C2Tx, representing a 66% increase compared to that of SnSe. This work sheds light on the thermoelectric performance improvement of polycrystalline SnSe by controllably incorporating two-dimensional MXene.

Modular Nanostructures Facilitate Low Thermal Conductivity and Ultra-High Thermoelectric Performance in n-Type SnSe.

Single crystals of SnSe have gained considerable attention in thermoelectrics due to their unprecedented thermoelectric performance. However, polycrystalline SnSe is more favorable for practical applications due to its facile chemical synthesis procedure, processability, and scalability. Though the thermoelectric figure of merit (zT) of p-type bulk SnSe polycrystals has reached >2.5, zT of n-type counterpart is still lower and lies around ≈1.5. Herein, record high zT of 2.0 in n-type polycrystalline SnSe0.92 + x mol% MoCl5 (x= 0-3) samples is reported, when measured parallel to the spark plasma sintering pressing direction due to the simultaneous optimization of n-type carrier concentration and enhanced phonon scattering by incorporating modular nano-heterostructures in SnSe matrix. Modular nanostructures of layered intergrowth [(SnSe)1.05 ]m (MoSe2 )n like compounds embedded in SnSe matrix scatters the phonons significantly leading to an ultra-low lattice thermal conductivity (κlat ) of ≈0.26W m-1 K-1 at 798 K in SnSe0.92 + 3 mol% MoCl5 . The 2D layered modular intergrowth compound resembles the nano-heterostructure and their periodicity of 1.2-2.6nm in the SnSe matrix matches the phonon mean free path of SnSe, thereby blocking the heat carrying phonons, which result in low κlat and ultra-high thermoelectric performance in n-type SnSe.

High thermoelectric and mechanical performance in the n-type polycrystalline SnSe incorporated with multi-walled carbon nanotubes

• A high ZT of ∼1.0 at 773 K and a high vickers hardness of >50 are simultaneously achieved in n-type SnSe. • MWCNTs act as “bridges” to accelerate the electron transport between n-SnSe grains. • MWCNTs act as phonon scattering centers to suppress the lattice thermal conductivity. • MWCNTs act as “binders” to bond adjacent n-SnSe grains and strengthen the hardness. In this study, we introduce multi-walled carbon nanotubes (MWCNTs) in Pb/I co-doped n-type polycrystal SnSe to simultaneously improve its thermoelectric and mechanical properties for the first time. The introduced MWCNTs act as the “bridges” to accelerate the electron carrier transport between SnSe grains, leading to significantly increased electrical conductivity from 32.6 to 45.7 S cm −1 at 773 K, which contributes to an enhanced power factor of ∼5.0 μW cm −1 K − 2 at this temperature. Although MWCNTs possess high intrinsic thermal conductivities, these MWCNTs, acting as nanoinclusions in the SnSe matrix to form the dense interfaces between SnSe and MWCNTs, provide extra heat-carrying phonon scattering centers, leading to a slightly reduced lattice thermal conductivity of only 0.34 W m − 1 K − 2 at 773 K and in turn, a high ZT of ∼1.0 at this temperature. Furthermore, the introduced MWCNTs can simultaneously act as the “binders” to bond adjacent grains, significantly improving the mechanical properties of SnSe by boosting its Vickers hardness from 39.5 to 50.5. This work indicates that our facile approach can achieve high thermoelectric and mechanical properties in n-type SnSe polycrystals with a considerable potential for applying to thermoelectric devices as n-type elements.

Realizing an enhanced Seebeck coefficient and extremely low thermal conductivity in anharmonic Sb-substituted SnSe nanostructures

Tin selenide (SnSe), an important thermoelectric material in the IV-VI chalcogenide family, has attracted significant attention for Thermoelectric power generation in the mid to high temperature (600–900 K) region. Herein, we report extremely low thermal conductivity and improved thermoelectric performance of polycrystalline SnSe through Sb substitution. Polycrystalline Sn1−xSbxSe (x = 0.01–0.05) was synthesized through a hydrothermal method followed through cold pressing technique. The existence of lone pair electrons induced the high lattice anharmonicity in Sb substituted SnSe, which reduced the thermal conductivity from enhanced the phonon scattering. Increasing Sb concentration drastically decreases the thermal conductivity to 0.23 W/mK at 640 K. Moreover, Sb substitution simultaneously enhanced the Seebeck coefficient 400 µV/K and the electrical conductivity value of 660 S/m at 550 K for X = 0.05 sample. It is observed that the aliovalent Sb substitution in the polycrystalline SnSe matrix exhibits an extreme reduction in thermal conductivity, which leads to high thermoelectric performance.

Multiple emerging nano-phases are at the origin of the low lattice thermal conductivity of SnSe?

Thermoelectrics are well recognized materials for energy harvesting and many solid-state cooling devices are already present on the market. SnSe is an inexpensive binary system made by earth-abundant elements that holds the record-high performance among the semiconductor materials although the origin of its ultralow thermal conductivity is still not understood. Both X-ray and neutron diffraction experiments identified in SnSe at high temperature a transition from the α-phase (Pnma) to the β-phase (Cmcm). In this contribution using for the first time in-situ temperature-dependent X-ray Absorption Fine structure spectroscopy (T-XAFS) at Sn and Se K-edge, we showed the occurrence in the XAS data of two isosbestic points, which support the coexistence of two phases in a wide temperature range. Moreover, in the SnSe matrix Sn–O bonds are continuously formed and SnO2, SeO2 and SnSe2 nanophases are emerging at high temperature. The experiment points out how these local nanophases are formed above 600 K. These emerging nano-phases affect the mean free path of phonons reducing the lattice thermal conductivity and, together with the crystal structural phase transition, may account for the low thermal conductivity measured in SnSe single crystals.

Effect of graphene on thermal stability of tin selenide

The thermal stability of polycrystalline tin selenide (SnSe) is essential for its long-term applications. In this study, the thermo-mechanical stability of hot compacted polycrystalline SnSe and SnSe/graphene nanocomposite is evaluated. All samples were prepared using a combination of mechanical alloying and hot compaction under an argon atmosphere. A severe bloating behavior was observed in the pristine SnSe hot compacted disks after post densification annealing. Consequently, these disks exhibited volume expansion and a drop in density, resulting in the formation of pores and cracks within the sample, which significantly degraded the electrical performance with consecutive thermal cyclings. Interestingly, the bloating behavior was reduced upon the incorporation of graphene within the SnSe matrix. However, this reduction was limited to samples with a homogeneous distribution of graphene. Dilatometer measurements showed that the as-compacted SnSe/graphene nanoplatelets (GNPs) sample in which graphene was milled for 4 h exhibited less hysteresis than the pristine SnSe sample. Accordingly, the electrical performance of the SnSe/GNP samples was more stable than the pristine SnSe after consecutive thermal cycles. The obtained results indicate that homogeneously distributed graphene plays a significant role in improving the thermal stability of the SnSe-based nanocomposite.

Enhancing the thermoelectric performance of SnSe by the introduction of Au nano dots

The electrical and thermal properties of thermoelectric performance can be decoupled by devising low-dimensional metal-semiconductor nanotechnology, which results to higher thermoelectric performance. In this work, 0D–2D (0 Dimension-2 Dimension) Au-SnSe nanocomposites with intensive interface barriers and beneficial phonon scattering were designed. Au NDs (nano dots) distributed on the surface of SnSe nanoplates, thereby forming the 0D–2D Au-SnSe nanocomposites. The Au NDs with abundant electrons were introduced to improve the electrical transportation properties while the 0D–2D nanostructure grain interfaces were designed to reduce phonons transportation property in comparison with the pure SnSe matrix. The interface barriers between Au NDs and SnSe nanoplates can effectively filter low energy holes and scatter mid and long wavelength phonons. As a consequence, the electrical conductivity of 1 mol% Au/SnSe nanocomposite is 2211.1 Sm−1 at 773 K, increasing by 174.2% with respect of that of pure SnSe, and, meanwhile, the thermal conductivity is 0.363 Wm−1 K−1, reducing by 11.2%. Attributed to the large enhancement in electrical transport and the diminution in thermal conductivity, a much higher ZT value of 0.6 is obtained for 1 mol% Au/SnSe nanocomposite at 773 K, which is in good contrast to 0.16 for pure SnSe nanoplates.

Effect of nanoinclusions on the lattice thermal conductivity of SnSe

We theoretically investigate the effect of nanoparticle(NP) inclusion on the lattice thermal conductivity (κ l ) of SnSe matrix. The theoretical approach involves the prediction of κ l by varying the radius (R), density (D 1), and volume fraction (ε) of NP in SnSe matrix. NP has strong anisotropic effect on the lattice thermal conductivity reduction along the crystallographic direction. We observe the existence of an optimal NP volume fraction that minimizes the nanocomposite's thermal conductivity. At room temperature, this value is found to be ε = 0.317 for which lattice thermal conductivity reduces by 35% with NP (R = 5 nm) compared to pure SnSe. An enhancement in the figure of merit (ZT) around room temperature opens up new opportunities for thermoelectric power generation at moderate temperatures. Even larger enhancement is possible in polycrystalline SnSe which will be helpful for thermoelectric devices.

Two-dimensional WSe2/SnSe p-n junctions secure ultrahigh thermoelectric performance in n-type Pb/I Co-doped polycrystalline SnSe

In this study, we, for the first time, introduce p-type two-dimensional (2D) WSe2 nanoinclusions in n-type Pb/I co-doped SnSe matrix to form WSe2/SnSe p-n junctions. These p-n junctions act as energy barriers and effective phonon scattering sources, leading to a high figure-of-merit (ZT) of ∼1.35 at ∼790 K in n-type polycrystalline SnSe. First-principles density functional theory calculation results indicates that I-doping shifts Fermi level up into conduction bands of SnSe, making the system n-type behavior, while both Pb and I dopants act as point-defect-based short-wavelength phonon scattering centers. The introduced p-type 2D WSe2 nanoinclusions induce high-density WSe2/SnSe interfaces that act as p-n junctions, which block the electron carriers and rationally tune the carrier density, contributing to a high absolute Seebeck coefficient of ∼470.7 μV K−1 and a high power factor of ∼5.9 μW cm−1 K−2. Meanwhile, the dense phase boundaries and considerable lattice strains by the introduced 2D WSe2 nanoinclusions significantly strengthen the mid- and long-wavelength phonon scattering, giving rise to a much low thermal conductivity of 0.35 W m−1 K−1 and in turn a high ZT of ∼1.35. This study provides a new strategy to achieve high thermoelectric performance in n-type polycrystalline SnSe.

High Thermoelectric Performance in the New Cubic Semiconductor AgSnSbSe3 by High-Entropy Engineering

We investigate the structural and physical properties of the AgSnmSbSem+2 system with m = 1-20 (i.e., SnSe matrix and ∼5-50% AgSbSe2) from atomic, nano, and macro length scales. We find the 50:50 composition, with m = 1 (i.e., AgSnSbSe3), forms a stable cation-disordered cubic rock-salt p-type semiconductor with a special multi-peak electronic valence band structure. AgSnSbSe3 has an intrinsically low lattice thermal conductivity of ∼0.47 W m-1 K-1 at 673 K owing to the synergy of cation disorder, phonon anharmonicity, low phonon velocity, and low-frequency optical modes. Furthermore, Te alloying on Se sites creates a quinary high-entropy NaCl-type solid solution AgSnSbSe3-xTex with randomly disordered cations and anions. The extra point defects and lattice dislocations lead to glass-like lattice thermal conductivities of ∼0.32 W m-1 K-1 at 723 K and higher hole carrier concentration than AgSnSbSe3. Concurrently, the Te alloying promotes greater convergence of the multiple valence band maxima in AgSnSbSe1.5Te1.5, the composition with the highest configurational entropy. Facilitated by these favorable modifications, we achieve a high average power factor of ∼9.54 μW cm-1 K-2 (400-773 K), a peak thermoelectric figure of merit ZT of 1.14 at 723 K, and a high average ZT of ∼1.0 over a wide temperature range of 400-773 K in AgSnSbSe1.5Te1.5.

From microstructure evolution to thermoelectric and mechanical properties enhancement of SnSe

Defect existing form and its evolution play an important role in the thermoelectric transport process. Here different forms of Pb into the SnSe system were introduced in order to improve the thermoelectric and mechanical properties of SnSe. Pb/SnSe samples were fabricated by vacuum melting, solid phase diffusion, spark plasma sintering and annealing treatment. The element valence mapping diagram and the X-ray photoelectron spectra (XPS) characteristic peaks of Pb show that a certain amount of elemental Pb exists in the initial state, and evolves into Pb2+ ion after annealing treatment. The micro-structure evolution leads to significant enhancement of the power factor and the ZT value. The power factor (PF) and the ZT value for Pb/SnSe increases to 623 μW/m/K2 and 1.12 at 773 K after annealing treatment, respectively. Compared with SnSe matrix, the hardness and fracture toughness of Pb/SnSe samples increased by about 40% and 10%, respectively. Reasonable control of microstructure evolution is expected to be a design idea to improve thermoelectric and mechanical properties of SnSe.

Realization of High Thermoelectric Figure of Merit in Solution Synthesized 2D SnSe Nanoplates via Ge Alloying.

Recently single crystals of layered SnSe have created a paramount importance in thermoelectrics owing to their ultralow lattice thermal conductivity and high thermoelectric figure of merit ( zT). However, nanocrystalline or polycrystalline SnSe offers a wide range of thermoelectric applications for the ease of its synthesis and machinability. Here, we demonstrate high zT of ∼2.1 at 873 K in two-dimensional nanoplates of Ge-doped SnSe synthesized by a simple hydrothermal route followed by spark plasma sintering (SPS). Anisotropic measurements also show a high zT of ∼1.75 at 873 K parallel to the SPS pressing direction. Ge doping (3 mol %) in SnSe nanoplates significantly enhances the p-type carrier concentration, which results in high electrical conductivity and power factor of ∼5.10 μW/cm K2 at 873 K. High lattice anharmonicity, nanoscale grain boundaries, and Ge precipitates in the SnSe matrix synergistically give rise to the ultralow lattice thermal conductivity of ∼0.18 W/mK at 873 K.

High Thermoelectric Performance in p‐type Polycrystalline Cd‐doped SnSe Achieved by a Combination of Cation Vacancies and Localized Lattice Engineering

AbstractHerein, a high figure of merit (ZT) of ≈1.7 at 823 K is reported in p‐type polycrystalline Cd‐doped SnSe by combining cation vacancies and localized‐lattice engineering. It is observed that the introduction of Cd atoms in SnSe lattice induce Sn vacancies, which act as p‐type dopants. A combination of facile solvothermal synthesis and fast spark plasma sintering technique boosts the Sn vacancy to a high level of ≈2.9%, which results in an optimum hole concentration of ≈2.6 × 1019 cm−3 and an improved power factor of ≈6.9 µW cm−1 K−2. Simultaneously, a low thermal conductivity of ≈0.33 W m−1 K−1 is achieved by effective phonon scattering at localized crystal imperfections, as observed by detailed structural characterizations. Density functional theory calculations reveal that the role of Cd atoms in the SnSe lattice is to reduce the formation energy of Sn vacancies, which in turn lower the Fermi level down into the valence bands, generating holes. This work explores the fundamental Cd‐doping mechanisms at the nanoscale in a SnSe matrix and demonstrates vacancy and localized‐lattice engineering as an effective approach to boosting thermoelectric performance. The work provides an avenue in achieving high‐performance thermoelectric properties of materials.

High Thermoelectric Performance in Polycrystalline SnSe Via Dual‐Doping with Ag/Na and Nanostructuring With Ag8SnSe6

AbstractSingle crystalline SnSe is one of the most intriguing new thermoelectric materials but the thermoelectric performance of polycrystalline SnSe seems to lag significantly compared to that of a single crystal. Here an effective strategy for enhancing the thermoelectric performance of p‐type polycrystalline SnSe by Ag/Na dual‐doping and Ag8SnSe6 (STSe) nanoprecipitates is reported. The Ag/Na dual‐doping leads to a two orders of magnitude increase in carrier concentration and a convergence of valence bands (VBM1 and VBM5), which in turn results in sharp enhancement of electrical conductivities and high Seebeck coefficients in the Ag/Na dual‐doped samples. Additionally, the SnSe matrix becomes nanostructured with dispersed nanoprecipitates of the compound Ag8SnSe6, which further strengthens the scattering of phonons. Specifically, ≈20% reduction in the already ultralow lattice thermal conductivity is realized for the Sn0.99Na0.01Se–STSe sample at 773 K compared to the thermal conductivity of pure SnSe. Consequently, a peak thermoelectric figure of merit ZT of 1.33 at 773 K with a high average ZT (ZTave) value of 0.91 (423–823 K) is achieved for the Sn0.99Na0.01Se–STSe sample.

Polycrystalline SnSe with Extraordinary Thermoelectric Property via Nanoporous Design.

Nanoporous materials possess low thermal conductivities derived from effective phonon scatterings at grain boundaries and interfaces. Thus nanoporous thermoelectric materials have full potential to improve their thermoelectric performance. Here we report a high ZT of 1.7 ± 0.2 at 823 K in p-type nanoporous polycrystalline SnSe fabricated via a facile solvothermal route. We successfully induce indium selenides (InSe y) nanoprecipitates in the as-synthesized SnSe matrix of single-crystal microplates, and the nanopores are achieved via the decompositions of these nanoprecipitates during the sintering process. Through detailed structural and chemical characterizations, it is found that the extralow thermal conductivity of 0.24 W m-1 K-1 caused by the effective phonon blocking and scattering at induced nanopores, interfaces, and grain boundaries and the high power factor of 5.06 μW cm-1 K-2 are derived from a well-tuned hole carrier concentration of 1.34 × 1019 cm-3 via inducing high Sn vacancies by self-doping, contributing to high ZTs. This study fills the gap of achieving nanoporous SnSe and provides an avenue in achieving high-performance thermoelectric properties of materials.