Jian Zhang

PbTe is recognized as one of the best intermediate-temperature thermoelectric materials; however, its commercial applications are largely restricted by the comparatively lower performance of its n-type counterpart. Here we show that Peierls-Nabarro stress is manipulated through solute-induced lattice softening, which generates high density helical dislocations, dislocation loops, and subgrain boundaries to block heat transport phonons. Concurrently, in-situ formation of Sb ₆ O ₁₃ nanoinclusions resulting from a displacement reaction between Sb and TeO ₂ further suppresses thermal transport, leading to an ultra-low lattice thermal conductivity ( κ _L ≈ 0.21 W m ⁻¹ K ⁻¹ at 773 K). Moreover, Sb doping can simultaneously enhance electronic density of states, leading to the improvement of power factor (16 μW cm ⁻¹ K ⁻² at 563 K). As a result, a remarkably high figure of merit ( ZT ≈ 2.2) is obtained at 723 K in n-type PbTe-1.5 wt%TeO ₂ -1.8 wt%Sb sample. Our findings provide an effective approach to synergistically improve the thermal and electrical properties in advanced thermoelectric materials.

PbBi2Te4 is regarded as a promising thermoelectric material due to its complex ternary layered structure. However, its intrinsically high carrier concentration limits its thermoelectric performance. To address this issue, Ni and Se doping was initially employed to modulate the carrier concentration. Nonetheless, the modest enhancement achieved through doping alone suggests that this strategy is insufficient to substantially improve the thermoelectric properties of PbBi2Te4. Subsequently, solid-state lithiation was systematically investigated as an alternative approach. The incorporation of Li ions into the PbBi2Te4 matrix effectively reduced the thermal conductivity, leading to a significant enhancement in thermoelectric performance. Specifically, after solid-state lithiation of the Ni- and Se-co-doped sample (PbNi0.04Bi1.96Te3.6Se0.4), a maximum figure of merit (ZT) of 0.54 was achieved at 590 K, corresponding to a 68% improvement over the ZTmax of pristine PbBi2Te4. Furthermore, an average ZT of 0.41 was obtained in the temperature range of 300–650 K, representing a 140% increase compared to that of the pristine sample over the same temperature range. These findings offer valuable insights for the further development of PbBi2Te4-based thermoelectric materials.

Antisite defects, as intrinsic point defects in crystals, have demonstrated significant potential in optimizing the thermoelectric performance of materials, particularly by modulating the carrier concentration. However, they typically degrade carrier mobility due to the strong coupling among thermoelectric parameters. To address this limitation, we propose a dual-antisite defects strategy: by introducing donor–acceptor defect pairs to form electrically neutral configurations, carrier scattering can be significantly reduced due to charge compensation. Meanwhile, the presence of these point defects still maintains strong phonon scattering. This approach minimizes the loss of electrical mobility while effectively suppressing lattice thermal conductivity (κ_L). Using chalcopyrite CuGaTe₂ as a matrix, we incorporated charge-balanced dual-antisite defects (Ag_Ga^″ and In_Cu^··) via alloying. This type of electrically neutral dual-antisite defects can maintain carrier mobility while increasing carrier concentration and significantly suppresses κ_L by enhancing phonon scattering through the interaction between alloy disorder scattering induced by In alloying and nanodomains. Remarkably, in Cu_0.7Ag_0.3Ga_0.6In_0.4Te₂, a record-high ZT value of 2.03 at 873 K was achieved. This dual-antisite defects strategy provides a new paradigm for defect engineering in thermoelectric materials, enabling the simultaneous optimization of electrical and thermal transport properties and offering a valid pathway toward high-performance thermoelectrics.

P-type PbTe is long recognized as an outstanding thermoelectric material in the moderate temperature range, while its n-type counterpart shows relatively poor performance. To address this issue and enhance the thermoelectric properties of n-type PbTe, indium (In) was selected as the dopant to synthesize a series of Pb1−xInxTe (0.03 ≤ x ≤ 0.038) compounds, aiming to regulate the electron concentration and transport characteristics due to the simultaneous increase in electron concentration and mobility, which could be ascribed to the lattice regularization and the reduction of Pb vacancies induced by In doping. As a result, the In-doped compound Pb0.966In0.034Te demonstrated superior thermoelectric performance. Subsequently, Pb0.966In0.034Te/f-CdSe composites were fabricated, and their thermoelectric properties were systematically investigated. The results revealed that In doping significantly increased the electrical conductivity of the materials importantly, and in situ reactions between CdSe and the Pb0.966In0.034Te matrix led to the formation of coherent CdIn2Te4 nanoparticles. The presence of these nanoparticles further enhanced the power factor of the composites across the entire investigated temperature range. Moreover, the lattice thermal conductivity of the composites decreased significantly due to the effective scattering of heat-carrying phonons by point defects and nano-interfaces. Consequently, the sample Pb0.966In0.034Te + 0.7 wt. % CdSe exhibited the optimal thermoelectric performance. At 703 K, its figure of merit (ZT) reached 1.3, representing a 34% increase compared to Pb0.966In0.034Te, and the average ZT reached 0.75. These findings indicate that incorporating CdSe into Pb0.966In0.034Te is an effective strategy to improve the thermoelectric performance of n-type PbTe.

Achieving a high power factor and low lattice thermal conductivity is crucial for improving the thermoelectric performance. The eco-friendly Cu₁₂Sb₄S₁₃ tetrahedrite inherently exhibits a high power factor (∼10-14 μW cm^-1 K^-2) and low thermal conductivity (0.5-1.00 W m^-1 K^-1), but these properties also impose significant limitations for further performance enhancement. To overcome these challenges, researchers have explored strategies such as codoping/synergistic element doping and nanocomposites. In this work, we demonstrate that Sn doping at the Sb site in Cu₁₂Sb₄S₁₃ (without the use of nanocomposites) enables the synergistic modulation of both the electronic and thermal properties. The Sn doping increases the hole concentration and enhances the density of states (DOS), leading to a marked improvement in the power factor (at 750 K), 12 μW cm^-1 K^-2 for x = 0 to 16 μW cm^-1 K^-2 for x = 0.04. Simultaneously, Sn doping induces strong phonon scattering, which lowers thermal conductivity by ∼69% (at 750 K). This synergistic modulation of the electronic structure, DOS, and scattering mechanisms results in a significant enhancement in the thermoelectric performance. The optimized Cu₁₂Sb_3.96Sn_0.04S₁₃ sample exhibits an exceptional figure of merit (ZT) of 1.26 at 750 K, representing a 126% increase compared to pristine Cu₁₂Sb₄S₁₃. These findings demonstrate the effectiveness of Sn doping in simultaneously optimizing the electrical and thermal properties of Cu₁₂Sb₄S₁₃ through the synergistic modulation of the electronic structure, density of states, and phonon scattering mechanisms.

Bi₂Te₃-based thermoelectric (TE) materials are the state-of-the-art compounds for commercial applications near room temperature. Nevertheless, the application of the n-type Bi₂Te_2.7Se_0.3 (BTS) is restricted by the comparatively low figure of merit (ZT) and intrinsic embrittlement. Here, we show that through dispersion of amorphous Si₃N₄ (a-Si₃N₄) nanoparticles both 14% increase in power factor (at 300 K) and 48% decrease in lattice thermal conductivity are simultaneously realized. The increased power factor comes from enhanced thermopower and reduced electrical resistivity while the reduced lattice thermal conductivity originates mainly from scattering of middle- and low-frequency phonons at the incorporated a-Si₃N₄ nanoparticles. As a result, a large ZT_max = 1.19 (at 373 K) and an average ZT_ave ∼ 1.12 (300–473 K) with better mechanical properties are achieved for the BTS/0.25 wt % Si₃N₄ sample. Present results demonstrate that the incorporation of a-Si₃N₄ is a promising way to improve TE performance.

Cryptococcus neoformans has been designated as critical fungal pathogens by the World Health Organization, mainly due to limited treatment options and the prevalence of antifungal resistance. Consequently, the utilization of novel antifungal agents is crucial for the effective treatment of C. neoformans infections. This study exposed that the minimum inhibitory concentration (MIC) of isobavachalcone (IBC) against C. neoformans H99 was 8 µg/mL, and IBC dispersed 48-h mature biofilms by affecting cell viability at 16 µg/mL. The antifungal efficacy of IBC was further validated through microscopic observations using specific dyes and in vitro assays, which confirmed the disruption of cell wall/membrane integrity. RNA-Seq analysis was employed to decipher the effect of IBC on the C. neoformans H99 transcriptomic profiles. Real-time quantitative reverse transcription PCR (RT-qPCR) analysis was performed to validate the transcriptomic data and identify the differentially expressed genes. The results showed that IBC exhibited various mechanisms to impede the growth, biofilm formation, and virulence of C. neoformans H99 by modulating multiple dysregulated pathways related to cell wall/membrane, drug resistance, apoptosis, and mitochondrial homeostasis. The transcriptomic findings were corroborated by the antioxidant analyses, antifungal drug sensitivity, molecular docking, capsule, and melanin assays. In vivo antifungal activity analysis demonstrated that IBC extended the lifespan of C. neoformans-infected Caenorhabditis elegans. Overall, the current study unveiled that IBC targeted multiple pathways simultaneously to inhibit growth significantly, biofilm formation, and virulence, as well as to disperse mature biofilms of C. neoformans H99 and induce cell death.