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By combining the effects of defect engineering, band convergence, and carrier concentration tuning, we successfully suppress the lattice thermal conductivity to ultra-low 0.35 W m−1 K−1 and realize one of the highest ZT values of 1.75 at 833 K.

The need for cognition has much promise in predicting academic success. This study examined the relationship between the need for cognition and the personality traits of openness to experience and conscientiousness. The goal was to show that openness to experience and conscientiousness were significant predictors of the need for cognition, while finding which one has stronger predictive power. The data was collected from 300 American users of the website Amazon Mechanical Turk who completed the study online in exchange for monetary compensation. The participants were composed of 154 males and 145 females, and one individual with unreported gender. The participants ranged from 20 years of age to 71 years of age, with an average age of 37.4. The need for cognition was measured using the Need for Cognition Scale. The two personality traits were measured using the Ten-Item Personality Inventory. The results of the study indicated that openness to experience was a stronger predictor of the need for cognition and predicted more variance in the need for cognition.

Thermoelectric technology is an effective strategy to convert low–grade waste heat to electrical energy directly. Thermoelectric generators (TEGs) have been extensively studied in various waste heat scenarios, such as vehicle exhaust, metal casting processes and more. However, industrial pipelines also possess high levels of heat and wide distribution, yet there is limited research on TEGs for use in these pipes. The challenge in designing a TEG lies in the heat collector, which is complicated by the distinct structural differences between pipe and plate–shaped TEMs. Ultimately, we propose an arch bridge–shaped heat collector for the pipe to recover wasted thermal energy. The effects of some key factors, such as topology of TEMs, heat source temperature, cooling water temperature and velocity, on the generating performance are studied. The TEG achieved a temperature difference of 65.98 °C across the two ends of the TEM, resulting in an output power of 17.89 W at an open–circuit voltage of 133.35 V. This provides evidence that the designed heat collector is a feasible solution for recovering waste heat from pipes using TEG technology. This work provides reliable experimental data and efficient design for the application of TEGs in industrial pipes.

A nano h-BN composite realizes a better thermoelectric performance of ZTmax = 1.3 at 375 K and significantly improves the compressive strength to 8.8 MPa in zone-melted Bi2Te3-based materials.

Zone-melted Bi2Te3-based alloys are the only commercially available thermoelectric (TE) materials, but they suffer from mediocre figure of merit (ZT) values and brittleness. In this work, we prepared Bi0.48Sb1.52Te3 sintered samples using a hot-pressing method and added tiny AgCuTe to improve the comprehensive properties. Because the carrier concentration is boosted by the AgCuTe addition, the bipolar effect at higher temperature is explicitly suppressed and the power factor is also improved in a broad temperature scope. Simultaneously, κlat is mostly diminished by the introduced phonon scattering centers comprising point defects, dislocations, and grain boundaries. Consequently, we achieved a ZTmax of 1.25 at 350 K and its average ZTave of 1.1 from 300 to 500 K in the (Bi0.48Sb1.52Te3 + 3 wt % Te) + 0.12 wt % AgCuTe sample. Composed of this sample and commercial Bi2Te2.5Se0.5, the fabricated TE module manifests a maximum power output density of 0.31 W cm-2 (Tcold = 300 K and Thot = 500 K). This work suggests that AgCuTe-doped Bi0.48Sb1.52Te3 is promising for recovering low-grade thermal energy near room temperature.

CREBBP, in short CBP, has been reported to be involved in tumorigenesis in various cancers, but its role in ovarian cancer remains largely unexplored. In our study, survival analysis of CBP in patients with ovarian cancer was conducted using the Kaplan-Meier Plotter database, then we utilized specific shRNA targeting CREBBP to block the expression of CBP, and detected its effect on cell proliferation and chemo-sensitivity in ovarian cancer cells. The results showed that high expression of CBP was correlated with poor prognosis in ovarian cancer patients. CREBBP knockdown in ovarian cancer cells significantly inhibited tumor proliferation both in vitro and in vivo. Moreover, CREBBP knockdown promoted chemo-sensitivity in ovarian cancer cells. Mechanism research further demonstrated that CREBBP knockdown attenuated unfolded protein response (UPR), which was mediated by PERK/ATF4/STC2 signaling pathway. Our research linked CBP and UPR in ovarian cancer and may provide new strategies for the clinical treatment of ovarian cancer.

Bismuth telluride alloys have dominated the industrial application of thermoelectric cooling, but the relatively poor mechanical performance of commercial zone-melting material seriously limits the device integration and stability. Here, we exhibit synergistically enhanced thermoelectric and mechanical performances of sintered Bi0.48Sb1.52Te3-AgSbSe2 composites. It is found that the increased hole concentration improves the S2σ to 40 μW cm-1 K-2 at room temperature, and the emerged various defects effectively suppress the κl to 0.57 W m-1 K-1 at 350 K. All effects harvest a highest ZT = 1.2 at 350 K along with an average ZT = 1.0 between 300-500 K in the x = 0.2 sample. Notably, AgSbSe2 addition not only optimizes the thermoelectric properties, but also enhances the mechanical performance with a Vickers hardness of 0.75 GPa. Furthermore, the isotropy of thermoelectric properties is also observably promoted by solid-phase reaction combined with high-energy ball milling and hot pressing. Our study reveals a viable strategy to improve the comprehensive performance of sintered bismuth telluride materials.

Bismuth telluride has been the only commercial thermoelectric candidate, but the n-type sintered material lags well behind the p-type one in the zT value, which severely limits the further development of thermoelectrics. Here, we report a promising technique named hot-stacked deformation to effectively improve the thermoelectric properties of n-type Bi2Te2.79Se0.21 + 0.067 wt % BiCl3 materials based on zone-melting ingots. It is found that a high grain alignment is maintained during the plastic deformation and the carrier concentration is properly optimized owing to the donor-like effect, leading to an enhanced power factor. Moreover, the lattice thermal conductivity is obviously suppressed due to the emerged phonon scattering centers of dense grain boundaries and dislocations. These effects synergistically yield a maximum zT value of 1.38 and an average zTave of 1.18 between 300 and 500 K in the hot-stacked deformed sample, which is approximately 42% higher than those of the zone-melting ingots.

Bismuth telluride alloys are the only commercialized thermoelectric materials, which have successfully realized the practical applications of active cooling and waste heat harvesting near room temp...

Dysregulated immune responses have now been recognized as an essential stimulator of ulcerative colitis (UC). Neutrophil extracellular traps (NET) were reported as the potential factor in sustaining mucosal inflammation in UC. NET formation further induces antineutrophil cytoplasm autoantibodies (ANCA) that serve as a biomarker in determining the severity of UC, which have a long half-life due to neonatal Fc receptor (FcRn)-mediated recycling. This study aimed to explore the role of the ANCA-NET cycle in UC and evaluate the potential of targeting FcRn in UC treatment. Dextran sodium sulfate-induced mice and rat models were used in this study. anti-rat FcRn monoclonal antibodies were used to block FcRn function in vivo. Disease activity index (DAI) and histopathological score (HS) were estimated to characterize the inflammation severity of UC. Serum concentrations of IgG, ANCA, TNF-α, IL-1β and CRP were measured using specific ELISA kits. Colonic NET-associated protein (NAP) expression was determined by western blotting. Serum ANCA and colonic NAPs showed a positive correlation that varied with changes in serum inflammation-related indexes (IRI; including TNF-α, IL-1β, and CRP) and DAI and HS in mice with UC. Blockade of FcRn significantly reduced serum ANCA levels and colonic NAP expression and effectively decreased serum IRIs, DAI, and HS in rats with UC. Especially during the inflammation recurrence period, blockade of FcRn exerted even better therapeutic effects in rats with UC than salazosulfapyridine. Our results show that anti-FcRn therapy has benefits in UC treatment through reduced colonic NET formation by accelerating serum ANCA clearance.

In the mid-temperature region, SnTe is a promising substitute for PbTe, whereas the thermoelectric (TE) property of pristine SnTe is severely limited by the good thermal conductivity and inferior Seebeck coefficient. In this research, we synergistically manipulate the interdependent TE parameters of SnTe-AgBiTe

Seebeck coefficient describes the temperature gradient induced voltage in thermoelectrics. Usually, to obtain a high Seebeck coefficient within a wide temperature range is difficult, as it is limited by the Goldsmid-Sharp relationship. In this work, the thermoelectric performance of PbSe-AgSbSe2 alloy is optimized by SbCl3 doping. Interestingly, the observed Seebeck coefficient hardly varies as temperature increases from 300 K to 830 K, and its absolute value is at a high level more than 250 μV K-1. By measuring the Hall effect, the anomalous Seebeck coefficient is attributed to the strongly temperature-dependent carrier concentration, which increases from 0.38 × 1019 cm-3 at 300 K to 3.91 × 1019 cm-3 at 830 K. Besides the high Seebeck coefficient, the alloyed compounds exhibit the very low thermal conductivity down to 0.59 W·m-1K-1 at 830 K. Finally, a peak ZT reaches 1.12 at 830 K. It is predicted that the performance of alloys could be further improved by enhancing the carrier concentration.

Retrosynthetic analysis is a canonical technique for planning the synthesis route of organic molecules in drug discovery and development. In this technique, the screening of synthetic tree branches requires accurate forward reaction prediction, but existing software is far from completing this step independently. Previous studies attempted to apply a neural network to forward reaction prediction, but the accuracy was not satisfying. Through using the Edit Vector-based description and extended-connectivity fingerprints to transform the reaction into a vector, this study focuses on the update of the neural network to improve the template-based forward reaction prediction. Hard-threshold activation and the target propagation algorithm are implemented by introducing mixed convex-combinatorial optimization. Comparative tests were conducted to explore the optimal hyperparameter set. Using 15,000 experimental reaction data extracted from granted United States patents, the proposed hard-threshold neural network was systematically trained and tested. The results demonstrated that a higher prediction accuracy was obtained than that for the traditional neural network with backpropagation algorithm. Some successfully predicted reaction examples are also briefly illustrated.

Thermoelectric generator (TEG) has important applications in automotive exhaust waste heat recovery. The Back propagation neural network (BP) can predict the electrical generating performance of TEG efficiently and accurately due to its advantage of being good at handing nonlinear data. However, BP algorithm is easy to fall into local optimum, and its training data usually have deviation since the data are obtained through the simulation software. Both of the problems will reduce the prediction accuracy. In order to further improve the prediction accuracy of BP algorithm, we use the genetic algorithm (GA) to optimize BP neural network by selection, crossover, and mutation operation. Meanwhile, we create a TEG for the heat waste recovery of automotive exhaust and test 84 groups of experimental data set to train the GA−BP prediction model to avoid the deviation caused by the simulation software. The results show that the prediction accuracy of the GA−BP model is better than that of the BP model. For the predicted values of output power and output voltage, the mean absolute percentage error (MAPE) increased to 2.83% and 2.28%, respectively, and the mean square error (MSE) is much smaller than the value before optimization, and the correlation coefficient (R2) of the network model is greater than 0.99.

Zone-melted Bi

Pharmaceutical excipients (PEs) are substances included in drug formulations. Recent studies have revealed that some PEs can affect the activity of metabolic enzymes and drug transporters, however, the effects of PEs on CYP2C8 and its interaction potential with drugs remain unclear. In this study, we evaluated the effects of Tween 80 and EL−35 on CYP2C8 in vitro and further investigated their impacts on the PK of paclitaxel (PTX) in rats after single or multiple doses. The in vitro study indicated that Tween 80 and EL−35 inhibited CYP2C8 activity in human and rat liver microsomes. EL−35 also decreased the expression of CYP2C8 in HepG2 cells. In the in vivo study, Tween 80 did not alter the PK of PTX after single or multiple doses, whereas EL−35 administered for 14 days significantly increased the AUC and MRT of PTX. Further analysis indicated that multiple-dose EL−35 reduced the expression of Cyp2c22 and production of 6-OH-PTX in the rat liver. Our study suggested that short-term exposure to both PEs did not affect the PK of PTX in rats, but multiple doses of EL−35 increased the AUC and MRT of PTX by downregulating the hepatic expression of Cyp2c22. Such effects should be taken into consideration during drug formulation and administration.

The layered chalcogenide SnSe has attracted great interest for its remarkable ZT records. Here, we report the excellent thermoelectric performance of n-type SnSe single crystals by alloying with PbBr2, where a maximum ZT of 2.1 at 770 K is achieved along the out-of-plane direction. Interestingly, we observed a sharp drop of the carrier mobility at PbBr2 content x = 3%, which terminates the continuous increase of ZT from x = 0.5% to x = 2%. It is shown that the anomalous decrease is due to the evolution of the Fermi surface driven by the enlargement of the out-of-plane axis. When 1% Sn is substituted by Ge, the restoration of the Fermi surface increases the ZT for the x = 3% sample by 200%. This study reveals the crucial role of the Fermi-surface dynamics in n-type SnSe, and the consequent strategy is confirmed to be highly efficient in the optimization of thermoelectric performance.

As an attractive lead-free thermoelectric candidate, GeTe-based materials have been intensively studied in recent years. However, the ZT value of pristine GeTe is limited around unit owing to the excessive hole concentration by intrinsic Ge vacancies. In this work, we report the synergistic enhancement of thermoelectric properties in rhombohedral GeTe by Bi–Zn codoping. It is found that Bi doping can effectively optimize the carrier concentration. Density functional calculations demonstrated that both Zn doping and the reduced c/a ratio by Bi doping could promote valence band convergence and Seebeck coefficient enhancement. Furthermore, lattice thermal conductivity is also significantly suppressed due to the Bi–Zn codoping introduced phonon scattering centers including point defects, Ge nano-precipitates, herringbone domains, twin boundaries, concentrated stress and density dislocations in the matrix. Consequently, a peak ZT of 2.0 at 700 K and a ZTave of 1.35 from 400 to 800 K are realized in Ge0.9Bi0.06Zn0.04Te.

Tin selenide (SnSe) is a promising thermoelectric material because of its advantageous electronic structure and low thermal conductivity. In this work, n-type polycrystalline SnSe0.95 doped with a new dopant NbCl5 was prepared using vacuum melting and hot-pressing (HP) methods, which resulted in a textured microstructure and anisotropic thermoelectric performance. Several state-of-the-art characterization studies via XRD, SEM, and XPS were conducted to analyze the crystal phase, microstructure, and composition of the samples. The TEM observation showed that large amounts of dislocations and nanocrystalline grains existed in our polycrystalline SnSe0.95, which resulted in lower thermal conductivity and better mechanical performance compared to previous reports. The electrical transport measurements along the parallel and perpendicular directions to the HP pressure revealed that the scattering behavior of charge carriers was complex and had a profound effect on the overall thermoelectric properties. Finally, a maximum ZT value of 1.22 at 790 K was attained in the 0.5% NbCl5-doped SnSe0.95 sample, which exceeds most of the n-type polycrystalline SnSe systems doped with other halides.

Bismuth telluride alloys have dominated the industrial application of thermoelectric cooling, but the relatively poor mechanical performance of commercial zone-melting material seriously limits the device integration and stability. Here, we exhibit synergistically enhanced thermoelectric and mechanical performances of sintered Bi

Bismuth telluride has been the only commercial thermoelectric candidate, but the n-type sintered material lags well behind the p-type one in the

Phonon engineering is a core stratagem to improve the thermoelectric performance, and multi-scale defects are expected to scatter a broad range of phonons and compress the lattice thermal conductivity. Here, we demonstrate obviously enhanced thermoelectric properties in Bi0.48Sb1.52Te3 alloy by a hot-pressing texture method along the axial direction of a zone-melted ingot. It is found that a plastic deformation of grain refinement and rearrangement occurs during the textured pressing process. Although the obtained power factor is slightly decreased, a large amount of grain boundaries emerges in the textured samples and dense dislocations are observed around the boundaries and inside the grains. These additional phonon scattering centers can effectively scatter the low- and mid-frequency phonons, and the corresponding lattice thermal conductivity is significantly reduced to only 50% of that of zone-melted samples. Consequently, the maximum figure of merit (ZT) reaches 1.44 at 330 K and the average ZT (300-380 K) reaches 1.38. This study suggests that the simple hot-pressing texture technique is a promising method to significantly optimize the cooling capacity of Bi0.48Sb1.52Te3-based thermoelectric refrigeration.

Recently, Mg3Sb2 attracted much research interest due to its competitive thermoelectric performance of ZT = 1.7 observed in n-type materials at 700 K. On the other hand, the thermoelectric performance of p-type Mg3Sb2 is found to be limited (ZT < 0.7) by the low power factor, originating in the less degenerate valence valleys. In this paper, we report a systematic theoretic investigation on the thermoelectric properties of Mg3Sb2 by using band structure and transport calculations. Starting with the careful analysis of the band structure, the characteristics of the valence and conduction bands are clarified. By raising the concept of crystal field screening, a scheme to increase the degeneracy of valence valleys is proposed. The expected band convergence is numerically confirmed in Ba-doped p-type Mg3Sb2, where a significantly improved ZT = 1.2 at 800 K is predicted. This study provides an applicable scheme for improving the thermoelectric performance of Mg3Sb2, and also it enriches the concept of band engineering for thermoelectrics.

Band engineering is an important experimental approach to increase the thermopower of thermoelectric materials, whereas the underlying mechanism has been barely clarified. In PbTe and SnTe, the effective dopants for band engineering, such as Sr, Mn, Cd, and Eu, seem to be randomly distributed on the periodic table. By constructing an analysis model from density functional calculations, the varied experimental observations are arranged into a unified phase diagram as a function of a single variable: the s orbital energy level. Consequently, several neglected effective dopants in previous studies are naturally identified. The analysis method is further applied to GeTe and GeSe, and two kinds of band engineering are theoretically suggested. In this study, the proposed method for electronic structure analysis enables us to design the band engineering directly from the periodic table, which we hope will encourage and accelerate more experimental and theoretical research studies in the thermoelectric field.

Recently, SnSe has attracted wide attention as a promising environment-friendly IV-VI thermoelectric material. Here, SnS is alloyed with Na-doped SnSe to decrease the thermal conductivity for better thermoelectric performance. Consistent with previous reports, the lattice constant and the band gap change linearly with increasing SnS, suggesting the formation of SnSe1-xSx solid solution. However, SnS nano-precipitations have been clearly observed, indicating the phase separation in the alloys. Moreover, the grain size decreases obviously with increasing SnS amount. The first-principles calculations show that the nano-precipitation is due to the positive formation energies for SnSe1-xSx in the small x region. Due to the structure engineering, the lattice thermal conductivity is greatly reduced in SnSe1-xSx samples, leading to a promising ZT of 1.35 for Na0.03Sn0.97Se0.7S0.3 at 816 K. Keywords: SnSe, Solid solution, Grain refinement, Thermal conductivity, Thermoelectric performance

Polycrystalline Sn1−xCuxSe samples have been prepared using hot pressing to study the Cu doping effect on carrier concentration in SnSe. Different from Ag, Cu doping decreases the carrier concentration of SnSe at room temperature. The carrier concentration of Cu doped samples increases obviously with temperature, becomes larger than the pristine sample above 523 K, and approaches the values of Na doped SnSe at 773 K. The enhanced carrier concentration leads to better electrical conductivity, resulting in higher power factors at high temperatures. Due to carrier optimization by Cu, a peak ZT of 0.66 is achieved in Sn0.98Cu0.02Se at 813 K.

Recently, tin selenide SnSe has attracted extensive attention for the reported excellent thermoelectric performance. By alloying with AgSbSe2, we observed that SnSe undergoes a phase transition from the orthorhombic structure to a cubic phase. The cubic SnSe exhibits some anomalous thermoelectric properties compared with common IV-VI cubic semiconductors, such as PbTe and SnTe. It is proven that cubic SnSe is not a trivial band semiconductor, whereas its band gap originates in the spin-orbit coupling effects. In this nontrivial semiconductor, the competing factors, Seebeck coefficient and electrical conductivity, can be simultaneously optimized. The peak ZT reaches 0.82 at 842 K in Sn0.4(AgSb)0.3Se. This study reveals that such spin-orbit semiconductors are a new class of promising thermoelectric materials, in which the thermoelectric performance strongly depends on the local spin-orbit coupling, besides the overall chemical bonding.

Synergistic effect of band convergence and resonant level could be manipulated in SnTe by co-doping In and Hg, leading to a potential thermoelectric performance enhancement in a much wider temperature range. In this work we carefully investigated thermoelectric properties of the In-Hg co-doped SnTe, synthesized by a hot pressing method. With this co-doping the Seebeck coefficients of the co-doped samples were greatly improved (over 50 μVK−1) at the room temperature. Although power factors of the In-Hg co-doped SnTe were also able to be optimized, the peak ZT (0.9 at 850 K in Sn0.98Bi0.02Te-1%HgInTe2), however, is not high enough when comparing to other co-doped SnTe systems. This may be caused by the relatively high lattice thermal conductivity. An apparent competition between band convergence doping and resonant level doping was observed in our experiment. The results suggest that band engineering via co-doping should be further understood in order to optimize the thermoelectric properties inside the material system.

SnSe has attracted increasing attention as a promising thermoelectric material. In this work, a horizontal vapor transfer method was developed to synthesize high-quality, fully dense, and stoichiometric SnSe single crystals, which enables an evaluation of the transport properties inherent to SnSe along the bc-plane. The electronic transport properties can be well-understood by a single parabolic band model with acoustic phonon scattering, enabling insights into the fundamental material parameters determining the electronic properties. The lattice thermal conductivity (κl) decreases from 2.0 W m–1 K–1 at 300 K to 0.55 W m–1 K–1 at 773 K. It is revealed that an increase in hole concentration, an involvement of low-lying bands for transport, and a further reduction in κl would all enable p-type SnSe to be a promising eco-friendly thermoelectric material. This work not only provides a fundamental understanding of the charge transport but also guides the further improvement of thermoelectric SnSe.

Bismuth-telluride-based alloys have been the state-of-art thermoelectric candidates near room temperature. However, sintered samples with higher ZT values in a wide temperature range are still urgently needed for further applications. Especially owing to the small band gap, the minority carriers are boosted at higher temperature and the thermoelectric properties are severely deteriorated. Here, we prepared p-type Bi0.35Sb1.65Te3-xSex samples by hot pressing to enlarge the band gap and suppress the bipolar excitation. Although the carrier concentrations are slightly increased by the tiny Se alloying, the Seebeck coefficients above 400 K are significantly improved, and the bipolar and lattice contributions to thermal transport are obviously reduced. The x = 0.04 sample thus achieves an average value of 1.1 between 300 and 500 K, and the constructed thermoelectric device produces an output power density of 0.36 W cm−2 and conversion efficiency of 5.24% at a temperature difference of 200 K. These results suggest that Se-doped Bi0.35Sb1.65Te3 is a robust candidate for low-grade heat harvest near room temperature.

SnTe is an attracted lead-free thermoelectric material, but the thermoelectric performance is severely limited by the high hole concentration, undesirable valence band structure and high thermal conductivity. In this work, we study the multiple effects of Mn Bi codoping in SnTe to synergistically improve the overall power factor and ZT values. It is found that the Mn Bi codoping effectively reduces the hole concentration to an optimal range. As expected, Mn and Bi doping obviously decreases the energy separation between the two valence band maxima, enabling pronounced band convergence and improved Seebeck coefficient. Moreover, Mn Bi codoping introduces various phonon scattering centers to scatter a wide spectrum of phonons for a suppressed lattice thermal conductivity of 0.67 W m−1 K−1 at 850 K. The synergy of these effects yields a peak ZT of 1.3 at 850 K and an average ZT of 0.68 (300–850 K) in Sn0.90Mn0.07Bi0.03Te, suggesting SnTe-based material a promising candidate for medium-temperature thermoelectric applications.

Bismuth-telluride-based alloys are the unique commercial thermoelectric materials near room temperature, and the commonly used zone-melting method is efficient for the mass production. Since the ZTs of zone-melted samples has stagnated around 1.2 for decades, it is urgent for the scientific and industrial societies to break through this bottleneck. Herein, we report simultaneously improved power factor and ZT values in p-type Bi0.48Sb1.52Te3 materials by the addition of amorphous boron and metal indium. B and In dopants not only effectively increase the hole concentration and the density of state effective mass, leading to a high power factor of 55 μW cm−1 K−2, but also introduce various phonon scattering centers to obviously suppress the lattice thermal conductivity. The synergistic effects yield a ZTmax of 1.45 at 350 K, as well as a ZTave of 1.20 and σS2ave of 41 μW cm−1 K−2 (300 ~ 500 K) in the Bi0.48Sb1.515In0.005Te3 + 0.6 wt% B sample, suggesting tiny B-In codoping is a promising strategy for the further development of bismuth telluride thermoelectrics.

A Horizontal Bridgman (HB) method was employed attempt to grow large size undoped SnSe single crystal. SnSe was crystallized under 2–3 °C/cm temperature gradient and cooled to room temperature at a rate of ∼25 °C/h to release thermal stress. SnSe crystals grown from liquid solution and volatilized vapor were obtained simultaneously. Two single crystals with size about 30 × 20 × 15 mm 3 and 35 × 15 × 15 mm 3 were peeled off from the liquid growth SnSe, which were reported to be the largest so far. The as-grown SnSe single crystal had standard orthorhombic Pnma space group at room temperature. Stoichiometry ratio of the crystal was measured Sn: Se = 1:1. The density of as-grown crystal is ∼6.16 g/cm 3 , which is very close to 100% of the theoretical value of SnSe. The obtained SnSe single crystal displayed p -type character with a carrier density of 5.1 × 10 17 cm −3 at room temperature. Thermoelectric properties in directions parallel and perpendicular to cleavage bc plane were analyzed, the maximum thermoelectric figure of merit ZT were ZT ∥ bc = 1.1 and ZT ⊥ bc = 0.24 near Pnma - Cmcm phase transition temperature.

Retrosynthetic analysis is the canonical technique to plan the synthesis route of organic molecules in medicine development. In this technique, the screening of synthetic tree branches requires accurate forward reaction prediction, but existing software is still far from completing this step independently. Previous studies have attempted to apply neural network in the forward reaction prediction, but the accuracy is not satisfying. Through using the Edit-based Description and Extended-Connectivity Fingerprints to transform reaction into vector, the presented work focuses on the update of neural network to improve the template-based forward reaction prediction. Hard-threshold activation and target propagation algorithm are implemented by introducing the mixed-convex combinatorial optimization. Comparative tests are conducted to explore the optimal hyperparameter set. Using 15 000 experimental reaction records from granted United States patents, the proposed hard-threshold neural network is systematically trained and tested. The results demonstrate that a higher prediction accuracy is obtained when compared to the traditional neural network with backpropagation algorithm. Indeed, the prediction accuracy of the proposed hard-threshold neural network can reach 73.9% which is higher than Coley’s result with 71.8% ( Coley et al. ACS Cent. Sci, 2017 ). Some successfully predicted reaction examples are also briefly discussed.

SnSe-based single crystal has attracted much attention due to its outstanding thermoelectric behaviors, however, the fabrication of large size crystal seems difficult as it is very easy to cleavage during crystal growth. In this work, a novel horizontal Bridgman method was employed to produce SnSe crystal with 3 mol% Ag substitute for Sn. The Sn0.97Ag0.03Se raw material was in-situ synthesized in the horizontal Bridgman furnace and the crystal was grown in a PBN crucible. B2O3 encapsulant was used to prevent Se volatilization. The as-grown Sn0.97Ag0.03Se crystal was about 105 g in weight and a 25 mm×20 mm×15 mm single crystal was obtained. The density of the single crystal of 6.178 g/cm3 close to the theoretical value was measured. X-ray powder diffraction measurement indicated Sn0.97Ag0.03Se single crystal had orthorhombic Pnma structure at room temperature. The thermoelectric properties along a axis were analyzed and the Figure-of-merit, ZT=0.95 was obtained at 793 K mainly due to the low thermal conductivity near the Pnma-Cmcm phase transition temperature.

SnTe has been known as a unique thermoelectric material to achieve the synergy of a resonant level and band convergence, originating from its characteristic band structure. In this work, we report an optimization of the two kinds of band engineering in In–Cd codoped SnTe. Owing to the complementary and competitive effects of the resonant level and band convergence, the location of the Fermi level is critical to the optimization. We show that the highest power factor and thermoelectric figure of merit ZT are reached by introducing Sn vacancies, rather than reducing Sn vacancies as normally done in SnTe. The peak ZT ∼ 1.1 appears at 850 K, while an overall enhanced ZTave of 0.54 between 300 and 850 K and an estimated conversion efficiency of 9% are obtained. This study discloses the non-trivial interplay between the resonant level and band convergence.

With multiple band valleys and intrinsic low thermal conductivity, rock-salt SnSe possesses great potential as a promising thermoelectric material. Herein, we prepare cubic SnSe–AgSbTe2 alloy and demonstrate the synergistically optimized electronic and thermal transport properties. For the former, AgSbTe2 alloying can tune the Fermi surface and promote the band flattening, concurrently improving the density of state effective mass and carrier concentration. For the latter, the strong phonon-defect scattering caused by AgSbTe2 alloying contributes to a great reduction of lattice thermal conductivity. Collectively, an obviously enhanced ZTmax of 1.00 at 820 K and ZTave of 0.70 (300–820 K) are achieved in Sn0.5Ag0.25Sb0.25Se0.5Te0.5. Moreover, AgSbTe2 alloying can also improve the mechanical property and the Vickers hardness reaches 1.90 Gpa, which is over four times higher than that of pristine SnSe.