This research employs density functional theory (DFT) within the GGA-PBE framework to investigate the structural, electronic, mechanical, and optical characteristics of lead-free fluoride-based double perovskites Na2LiXF6 (X = Al, Ga, In, Tl). All compounds are found to crystallize in a stable cubic Fmm structure, with Goldschmidt tolerance factors confirming their structural integrity. The materials exhibit direct band gaps at the Γ-point, which decrease progressively from 6.83 eV (for Al) to 3.32 eV (for Tl), indicating potential suitability for UV to near-visible optoelectronic applications. The calculated elastic constants verify mechanical stability, showing an increasing trend in ductility with heavier atomic masses. Optical evaluations demonstrate strong transparency in the UV region, distinct dielectric responses, and absorption and reflectivity patterns consistent with band gap variation. Overall, Na2LiXF6 compounds emerge as promising lead-free candidates for efficient optoelectronic device applications.
本研究采用GGA-PBE框架内的密度泛函理论（DFT）研究了无铅氟基双钙钛矿Na2LiXF6 （X = Al, Ga, In, Tl）的结构、电子、机械和光学特性。发现所有化合物结晶在一个稳定的立方Fm3 - m结构中，戈德施密特公差系数证实了它们的结构完整性。材料在Γ-point处表现出直接带隙，从6.83 eV （Al）逐渐减小到3.32 eV (Tl)，表明潜在的紫外到近可见光电应用的适用性。计算得到的弹性常数证实了材料的力学稳定性，表明随着原子质量的增加，材料的延展性有增加的趋势。光学评价表明，该材料在紫外区具有很强的透明度，具有明显的介电响应，吸收和反射率模式与带隙变化一致。总的来说，Na2LiXF6化合物是高效光电器件应用的有前途的无铅候选者。
{"title":"Computational design of Na2LiXF6 (X = Al, Ga, In, Tl) alkali halide perovskites for emerging optoelectronic technologies","authors":"Md. Mahin Tasdid , Md. Rubayed Hasan Pramanik , Aijaz Rasool Chaudhry , Ahmad Irfan , Nacer Badi , Md. Ferdous Rahman","doi":"10.1016/j.solidstatesciences.2025.108133","DOIUrl":"10.1016/j.solidstatesciences.2025.108133","url":null,"abstract":"<div><div>This research employs density functional theory (DFT) within the GGA-PBE framework to investigate the structural, electronic, mechanical, and optical characteristics of lead-free fluoride-based double perovskites Na<sub>2</sub>LiXF<sub>6</sub> (X = Al, Ga, In, Tl). All compounds are found to crystallize in a stable cubic Fm<span><math><mrow><mover><mn>3</mn><mo>‾</mo></mover></mrow></math></span>m structure, with Goldschmidt tolerance factors confirming their structural integrity. The materials exhibit direct band gaps at the Γ-point, which decrease progressively from 6.83 eV (for Al) to 3.32 eV (for Tl), indicating potential suitability for UV to near-visible optoelectronic applications. The calculated elastic constants verify mechanical stability, showing an increasing trend in ductility with heavier atomic masses. Optical evaluations demonstrate strong transparency in the UV region, distinct dielectric responses, and absorption and reflectivity patterns consistent with band gap variation. Overall, Na<sub>2</sub>LiXF<sub>6</sub> compounds emerge as promising lead-free candidates for efficient optoelectronic device applications.</div></div>","PeriodicalId":432,"journal":{"name":"Solid State Sciences","volume":"170 ","pages":"Article 108133"},"PeriodicalIF":3.3,"publicationDate":"2025-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145517872","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-13DOI: 10.1016/j.solidstatesciences.2025.108136
Mehdi Akermi , Mohamed Ben Bechir
We establish a coherent structure–property framework for the hybrid halide [N(CH3)3H]2CdCl4 by integrating crystallography, thermal analysis, broadband optics, photodynamics, and dielectric spectroscopy. Powder X-ray diffraction confirms an orthorhombic, non-centrosymmetric phase (Pna21) supported by STEM–EDS and vibrational fingerprints of [CdCl4]2− units and trimethylammonium cations. Thermogravimetry shows no mass loss up to ∼533 K, underscoring robust stability well above the phase-transition window. Differential scanning calorimetry resolves two reversible transitions at 253/263 K and 290/300 K with ∼10 K hysteresis and order–disorder entropies. Diffuse-reflectance UV–Vis treated via the Kubelka–Munk transform (α/S vs hν) reveals a direct band gap Eg (298 K) = 4.18 eV, narrowing to ∼4.10 eV at 350 K, accompanied by a modest red shift and an emergent Urbach tail indicative of strengthened exciton–phonon coupling. Consistently, steady-state PL (peak ∼472 nm) red-shifts, broadens (FWHM ∼105 → ∼125 nm), and quenches by ∼22 % on heating, while TRPL lifetimes contract (⟨τ⟩ ≈ 22 → ∼9 ns), signaling thermally activated non-radiative channels. Temperature-dependent permittivity exhibits step-like switching with ∼10 K hysteresis and minimal dispersion across 20–106 Hz, mirroring the calorimetric transitions and consolidating an opto-lattice coupling scenario in which lattice reorganizations regulate both band-edge and emissive dynamics. These cross-validated correlations position [N(CH3)3H]2CdCl4 as a promising platform for stimuli-responsive dielectrics and UV–Vis–NIR photonic functions.
{"title":"Opto-lattice coupling and thermally switchable dielectric transition in [N(CH3)3H]2CdCl4","authors":"Mehdi Akermi , Mohamed Ben Bechir","doi":"10.1016/j.solidstatesciences.2025.108136","DOIUrl":"10.1016/j.solidstatesciences.2025.108136","url":null,"abstract":"<div><div>We establish a coherent structure–property framework for the hybrid halide [N(CH<sub>3</sub>)<sub>3</sub>H]<sub>2</sub>CdCl<sub>4</sub> by integrating crystallography, thermal analysis, broadband optics, photodynamics, and dielectric spectroscopy. Powder X-ray diffraction confirms an orthorhombic, non-centrosymmetric phase (<em>Pna</em>2<sub>1</sub>) supported by STEM–EDS and vibrational fingerprints of [CdCl<sub>4</sub>]<sup>2−</sup> units and trimethylammonium cations. Thermogravimetry shows no mass loss up to ∼533 K, underscoring robust stability well above the phase-transition window. Differential scanning calorimetry resolves two reversible transitions at 253/263 K and 290/300 K with ∼10 K hysteresis and order–disorder entropies. Diffuse-reflectance UV–Vis treated via the Kubelka–Munk transform (α/S vs hν) reveals a direct band gap E<sub>g</sub> (298 K) = 4.18 eV, narrowing to ∼4.10 eV at 350 K, accompanied by a modest red shift and an emergent Urbach tail indicative of strengthened exciton–phonon coupling. Consistently, steady-state PL (peak ∼472 nm) red-shifts, broadens (FWHM ∼105 → ∼125 nm), and quenches by ∼22 % on heating, while TRPL lifetimes contract (⟨τ⟩ ≈ 22 → ∼9 ns), signaling thermally activated non-radiative channels. Temperature-dependent permittivity exhibits step-like switching with ∼10 K hysteresis and minimal dispersion across 20–10<sup>6</sup> Hz, mirroring the calorimetric transitions and consolidating an opto-lattice coupling scenario in which lattice reorganizations regulate both band-edge and emissive dynamics. These cross-validated correlations position [N(CH<sub>3</sub>)<sub>3</sub>H]<sub>2</sub>CdCl<sub>4</sub> as a promising platform for stimuli-responsive dielectrics and UV–Vis–NIR photonic functions.</div></div>","PeriodicalId":432,"journal":{"name":"Solid State Sciences","volume":"170 ","pages":"Article 108136"},"PeriodicalIF":3.3,"publicationDate":"2025-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145517384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-12DOI: 10.1016/j.solidstatesciences.2025.108134
Mohamed Bouzidi , Dhaifallah R. Almalawi , Idris H. Smaili , N.I. Aljuraide , Ali Alzahrani , A. Saftah , Mohamed Ben Bechir
This study presents a comprehensive investigation of the optoelectronic properties of Cs2AgBiCl6, a promising lead-free double perovskite material. UV–Vis absorption measurements reveal an indirect bandgap of approximately 2.61 eV, consistent with other lead-free perovskites. Photoluminescence (PL) and time-resolved photoluminescence (TRPL) analyses highlight a large Stokes shift and two distinct recombination pathways, involving a fast decay component associated with shallow traps and a slower, long-lived process attributed to self-trapped excitons (STEs) or polarons. Transient absorption spectroscopy (TAS) further elucidates carrier dynamics, confirming the material’s suitability for advanced photonic applications. Raman spectroscopy reveals light-induced structural modifications and enhanced electron–phonon coupling, which promote the stabilization of excitonic species. Impedance spectroscopy measurements demonstrate that illumination significantly enhances charge-carrier mobility and conductivity, indicating a transition in the conduction mechanism from overlapping large-polaron tunneling (OLPT) in the dark to correlated barrier hopping (CBH) under illumination. Overall, Cs2AgBiCl6 exhibits characteristic semiconducting behavior with tunable charge-transport properties and enhanced photoresponse, making it a strong candidate for next-generation optoelectronic devices, including photodetectors and light-harvesting systems.
{"title":"Light-induced charge transport and carrier dynamics in lead-free Cs2AgBiCl6 double perovskite: Toward stable optical materials for photonic applications","authors":"Mohamed Bouzidi , Dhaifallah R. Almalawi , Idris H. Smaili , N.I. Aljuraide , Ali Alzahrani , A. Saftah , Mohamed Ben Bechir","doi":"10.1016/j.solidstatesciences.2025.108134","DOIUrl":"10.1016/j.solidstatesciences.2025.108134","url":null,"abstract":"<div><div>This study presents a comprehensive investigation of the optoelectronic properties of Cs<sub>2</sub>AgBiCl<sub>6</sub>, a promising lead-free double perovskite material. UV–Vis absorption measurements reveal an indirect bandgap of approximately 2.61 eV, consistent with other lead-free perovskites. Photoluminescence (PL) and time-resolved photoluminescence (TRPL) analyses highlight a large Stokes shift and two distinct recombination pathways, involving a fast decay component associated with shallow traps and a slower, long-lived process attributed to self-trapped excitons (STEs) or polarons. Transient absorption spectroscopy (TAS) further elucidates carrier dynamics, confirming the material’s suitability for advanced photonic applications. Raman spectroscopy reveals light-induced structural modifications and enhanced electron–phonon coupling, which promote the stabilization of excitonic species. Impedance spectroscopy measurements demonstrate that illumination significantly enhances charge-carrier mobility and conductivity, indicating a transition in the conduction mechanism from overlapping large-polaron tunneling (OLPT) in the dark to correlated barrier hopping (CBH) under illumination. Overall, Cs<sub>2</sub>AgBiCl<sub>6</sub> exhibits characteristic semiconducting behavior with tunable charge-transport properties and enhanced photoresponse, making it a strong candidate for next-generation optoelectronic devices, including photodetectors and light-harvesting systems.</div></div>","PeriodicalId":432,"journal":{"name":"Solid State Sciences","volume":"170 ","pages":"Article 108134"},"PeriodicalIF":3.3,"publicationDate":"2025-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145569180","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-12DOI: 10.1016/j.solidstatesciences.2025.108131
Sachin V. Desarada , Shweta N. Chaure , Vijaya S. Vallabhapurapu , Sreedevi Vallabhapurapu , Nandu B. Chaure
We report a rapid thermal processing (RTP) technique for post-processing the selenization and sulfurization of CuInGaSe2 (CIGS) thin films. CIGS films fabricated via RF-sputtering were exposed to cyclic RTP in elemental sulfur and selenium vapor atmospheres. Sulfurization was performed at 300–700 °C with multiple cycles of 10-s pulses, while selenization employed 350–450 °C. Comprehensive characterization using Raman spectroscopy, XRD with Rietveld refinement, SEM, UV–Vis spectroscopy, and EDS revealed controlled S/(S + Se) tuning from 0.10 to 0.63 during sulfurization and bandgap modulation from 1.08 to 1.24 eV. Single-phase CuInGa(S,Se)2 formation was confirmed at 500 °C. Crystallite size increased from 27 nm for as-deposited to 78 nm for RTP annealed sample, with proportional microstrain reduction. RTP enables 50–60 % faster processing compared to conventional tube furnace methods, significantly reducing thermal budget while maintaining precise compositional control. This approach eliminates toxic H2S and H2Se gases, making it suitable for industrial-scale manufacturing of bandgap-engineered CIGS solar cells and tandem photovoltaic applications.
{"title":"Bandgap engineering of CIGS thin films via rapid thermal processing for photovoltaic applications","authors":"Sachin V. Desarada , Shweta N. Chaure , Vijaya S. Vallabhapurapu , Sreedevi Vallabhapurapu , Nandu B. Chaure","doi":"10.1016/j.solidstatesciences.2025.108131","DOIUrl":"10.1016/j.solidstatesciences.2025.108131","url":null,"abstract":"<div><div>We report a rapid thermal processing (RTP) technique for post-processing the selenization and sulfurization of CuInGaSe<sub>2</sub> (CIGS) thin films. CIGS films fabricated via RF-sputtering were exposed to cyclic RTP in elemental sulfur and selenium vapor atmospheres. Sulfurization was performed at 300–700 °C with multiple cycles of 10-s pulses, while selenization employed 350–450 °C. Comprehensive characterization using Raman spectroscopy, XRD with Rietveld refinement, SEM, UV–Vis spectroscopy, and EDS revealed controlled S/(S + Se) tuning from 0.10 to 0.63 during sulfurization and bandgap modulation from 1.08 to 1.24 eV. Single-phase CuInGa(S,Se)<sub>2</sub> formation was confirmed at 500 °C. Crystallite size increased from 27 nm for as-deposited to 78 nm for RTP annealed sample, with proportional microstrain reduction. RTP enables 50–60 % faster processing compared to conventional tube furnace methods, significantly reducing thermal budget while maintaining precise compositional control. This approach eliminates toxic H<sub>2</sub>S and H<sub>2</sub>Se gases, making it suitable for industrial-scale manufacturing of bandgap-engineered CIGS solar cells and tandem photovoltaic applications.</div></div>","PeriodicalId":432,"journal":{"name":"Solid State Sciences","volume":"170 ","pages":"Article 108131"},"PeriodicalIF":3.3,"publicationDate":"2025-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145569112","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-11DOI: 10.1016/j.solidstatesciences.2025.108132
Anwarul Haq , S.M. Sohail Gilani , M. Amin , Fadiyah Antar Makin , Hala Siddiq , Tasawer Shahzad Ahmad , Altaf Ur Rahman , Ramash Sharma , A.A. Mubarak
This study employs DFT to predict the structural, mechanical, and optoelectronic properties of Rb2CuB'Cl6 (where B' = Ga, In). The Goldschmidt tolerance factor and modified tolerance factor values for these compounds fall within the specified ranges, indicating a structurally stable double halide perovskite structure. Analysis using the Global Instability Index indicates that Rb2CuInCl6 exhibits higher stability compared to Rb2CuGaCl6. First-principles molecular dynamics simulations were performed at 600 K for 20 ps. The stable total energy fluctuations confirmed their thermodynamic stability. Additionally, phonon band structure analysis revealed no negative frequencies at the Γ point, demonstrating their dynamic stability. Additionally, the negative enthalpy of these compounds further demonstrates their stability. The calculated direct bandgaps, with and without spin-orbit coupling, are 1.26 eV and 1.33 eV for Rb2CuGaCl6, and 1.60 eV and 1.65 eV for Rb2CuInCl6, respectively. These appropriately narrow bandgaps facilitate visible-light absorption, resulting in high absorption coefficients α(ω) ≈ 7.0 × 104 cm−1 for Rb2CuGaCl6 and 4.2 × 104 cm−1 for Rb2CuInCl6. High conductivity, and low reflectivity (R(ω)), making them promising semiconductors for optoelectronic applications. The evaluation of thermoelectric and transport properties revealed that the perovskite Rb2CuXCl6 (X = Ga, In) boasts a higher electronic figure of merit, highlighting its potential for thermoelectric applications.
{"title":"Lead-free Rb2CuXCl6 (X = Ga, In) double perovskites: A first-principles approach to energy loss, elasticity, and energy conversion properties","authors":"Anwarul Haq , S.M. Sohail Gilani , M. Amin , Fadiyah Antar Makin , Hala Siddiq , Tasawer Shahzad Ahmad , Altaf Ur Rahman , Ramash Sharma , A.A. Mubarak","doi":"10.1016/j.solidstatesciences.2025.108132","DOIUrl":"10.1016/j.solidstatesciences.2025.108132","url":null,"abstract":"<div><div>This study employs DFT to predict the structural, mechanical, and optoelectronic properties of Rb<sub>2</sub>CuB'Cl<sub>6</sub> (where B' = Ga, In). The Goldschmidt tolerance factor and modified tolerance factor values for these compounds fall within the specified ranges, indicating a structurally stable double halide perovskite structure. Analysis using the Global Instability Index indicates that Rb<sub>2</sub>CuInCl<sub>6</sub> exhibits higher stability compared to Rb<sub>2</sub>CuGaCl<sub>6</sub>. First-principles molecular dynamics simulations were performed at 600 K for 20 ps. The stable total energy fluctuations confirmed their thermodynamic stability. Additionally, phonon band structure analysis revealed no negative frequencies at the Γ point, demonstrating their dynamic stability. Additionally, the negative enthalpy of these compounds further demonstrates their stability. The calculated direct bandgaps, with and without spin-orbit coupling, are 1.26 eV and 1.33 eV for Rb<sub>2</sub>CuGaCl<sub>6</sub>, and 1.60 eV and 1.65 eV for Rb<sub>2</sub>CuInCl<sub>6</sub>, respectively. These appropriately narrow bandgaps facilitate visible-light absorption, resulting in high absorption coefficients α(ω) ≈ 7.0 × 10<sup>4</sup> cm<sup>−1</sup> for Rb<sub>2</sub>CuGaCl<sub>6</sub> and 4.2 × 10<sup>4</sup> cm<sup>−1</sup> for Rb<sub>2</sub>CuInCl<sub>6</sub>. High conductivity, and low reflectivity (R(ω)), making them promising semiconductors for optoelectronic applications. The evaluation of thermoelectric and transport properties revealed that the perovskite Rb<sub>2</sub>CuXCl<sub>6</sub> (X = Ga, In) boasts a higher electronic figure of merit, highlighting its potential for thermoelectric applications.</div></div>","PeriodicalId":432,"journal":{"name":"Solid State Sciences","volume":"171 ","pages":"Article 108132"},"PeriodicalIF":3.3,"publicationDate":"2025-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145622577","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-07DOI: 10.1016/j.solidstatesciences.2025.108130
Artem P. Tarutin , Gennady K. Vdovin , Dmitry A. Medvedev
Layered nickelate phases represent a convenient matrix for designing complex oxides intended for high-temperature applications. This study examines the structural, electrical, and electrochemical properties of the novel Pr1.8–xLaxBa0.2NiO4+δ (x = 0.0–0.8) materials as potential air electrodes for reversible solid oxide cells (rSOCs). Additionally, we attempted to study the hydration ability of these materials. These materials are based on the Ruddlesden-Popper phase, Pr2NiO4+δ, which is known for its mixed ionic-electronic transport behavior and favorable oxygen-diffusion characteristics. Substituting praseodymium with lanthanum and barium partially enhances the phase stability and optimizes the defect chemistry, improving the electrochemical performance of the designed electrodes. Compared with traditional perovskite and Ruddlesden-Popper cathode materials, the proposed electrode materials demonstrate superior surface oxygen exchange kinetics and thermal stability, positioning them as promising candidates for long-term rSOC applications.
{"title":"Ba and La co-doped Pr2NiO4+δ materials: Relationships between defect structure, thermal, and electrochemical properties","authors":"Artem P. Tarutin , Gennady K. Vdovin , Dmitry A. Medvedev","doi":"10.1016/j.solidstatesciences.2025.108130","DOIUrl":"10.1016/j.solidstatesciences.2025.108130","url":null,"abstract":"<div><div>Layered nickelate phases represent a convenient matrix for designing complex oxides intended for high-temperature applications. This study examines the structural, electrical, and electrochemical properties of the novel Pr<sub>1.8–x</sub>La<sub>x</sub>Ba<sub>0.2</sub>NiO<sub>4+δ</sub> (x = 0.0–0.8) materials as potential air electrodes for reversible solid oxide cells (rSOCs). Additionally, we attempted to study the hydration ability of these materials. These materials are based on the Ruddlesden-Popper phase, Pr<sub>2</sub>NiO<sub>4+δ</sub>, which is known for its mixed ionic-electronic transport behavior and favorable oxygen-diffusion characteristics. Substituting praseodymium with lanthanum and barium partially enhances the phase stability and optimizes the defect chemistry, improving the electrochemical performance of the designed electrodes. Compared with traditional perovskite and Ruddlesden-Popper cathode materials, the proposed electrode materials demonstrate superior surface oxygen exchange kinetics and thermal stability, positioning them as promising candidates for long-term rSOC applications.</div></div>","PeriodicalId":432,"journal":{"name":"Solid State Sciences","volume":"171 ","pages":"Article 108130"},"PeriodicalIF":3.3,"publicationDate":"2025-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145622661","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-06DOI: 10.1016/j.solidstatesciences.2025.108128
Dianta Ginting , Jong-Soo Rhyee
Topological crystalline insulators (TCIs) have revolutionized the design of thermoelectric materials by providing unprecedented opportunities to decouple electrical and thermal transport through quantum-protected surface states and strategic band engineering. This comprehensive review examines the exceptional thermoelectric performance enhancements achieved in Pb1-xSnxTe systems through synergistic exploitation of their topological nature and advanced nanostructuring strategies. The critical composition range x = 0.35–0.5 represents a topological phase transition where band inversion creates protected surface states while simultaneously enabling optimal bulk electronic structure modification. Strategic band engineering approaches—including compositional tuning via Se/S alloying (achieving band convergence), resonant doping with Na/K/Cl (optimizing carrier concentration), and valley convergence mechanisms—enable precise electronic property control while preserving topological characteristics. Complementary nanostructuring methodologies through hierarchical architectures spanning atomic-scale defects to mesoscale precipitates (2–10 nm) successfully decouple electronic and thermal transport via selective phonon scattering mechanisms. The most effective optimization strategies combine L-Σ valence band convergence with controlled nanoprecipitate formation, achieving remarkable ZT values up to 1.9 at 773-823 K—representing 300–1200 % enhancement over pristine compounds. Critical analysis reveals that weak topological perturbations (≤5 % alloying) maximize performance by maintaining beneficial band dispersion characteristics, while excessive disruption degrades both surface states and bulk transport properties. These findings establish fundamental design principles for next-generation topological thermoelectrics: (1) maintaining crystalline mirror symmetries during processing, (2) optimizing grain sizes (80–120 nm) for surface state preservation, (3) achieving optimal band convergence without destroying topological protection, and (4) implementing hierarchical phonon scattering while preserving electrical percolation. This review synthesizes current understanding of topology-enhanced transport phenomena and provides comprehensive guidance for developing superior thermoelectric materials that harness quantum protection mechanisms for practical energy conversion applications.
{"title":"Review: Enhancing thermoelectric performance by simultaneous band engineering, nanostructuring, and topological phase transition in topological crystal insulator Pb1-xSnxTe (x=0.4 and x=0.5)","authors":"Dianta Ginting , Jong-Soo Rhyee","doi":"10.1016/j.solidstatesciences.2025.108128","DOIUrl":"10.1016/j.solidstatesciences.2025.108128","url":null,"abstract":"<div><div>Topological crystalline insulators (TCIs) have revolutionized the design of thermoelectric materials by providing unprecedented opportunities to decouple electrical and thermal transport through quantum-protected surface states and strategic band engineering. This comprehensive review examines the exceptional thermoelectric performance enhancements achieved in Pb<sub>1-x</sub>Sn<sub>x</sub>Te systems through synergistic exploitation of their topological nature and advanced nanostructuring strategies. The critical composition range x = 0.35–0.5 represents a topological phase transition where band inversion creates protected surface states while simultaneously enabling optimal bulk electronic structure modification. Strategic band engineering approaches—including compositional tuning via Se/S alloying (achieving band convergence), resonant doping with Na/K/Cl (optimizing carrier concentration), and valley convergence mechanisms—enable precise electronic property control while preserving topological characteristics. Complementary nanostructuring methodologies through hierarchical architectures spanning atomic-scale defects to mesoscale precipitates (2–10 nm) successfully decouple electronic and thermal transport via selective phonon scattering mechanisms. The most effective optimization strategies combine L-Σ valence band convergence with controlled nanoprecipitate formation, achieving remarkable ZT values up to 1.9 at 773-823 K—representing 300–1200 % enhancement over pristine compounds. Critical analysis reveals that weak topological perturbations (≤5 % alloying) maximize performance by maintaining beneficial band dispersion characteristics, while excessive disruption degrades both surface states and bulk transport properties. These findings establish fundamental design principles for next-generation topological thermoelectrics: (1) maintaining crystalline mirror symmetries during processing, (2) optimizing grain sizes (80–120 nm) for surface state preservation, (3) achieving optimal band convergence without destroying topological protection, and (4) implementing hierarchical phonon scattering while preserving electrical percolation. This review synthesizes current understanding of topology-enhanced transport phenomena and provides comprehensive guidance for developing superior thermoelectric materials that harness quantum protection mechanisms for practical energy conversion applications.</div></div>","PeriodicalId":432,"journal":{"name":"Solid State Sciences","volume":"170 ","pages":"Article 108128"},"PeriodicalIF":3.3,"publicationDate":"2025-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145517881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-03DOI: 10.1016/j.solidstatesciences.2025.108129
E.P. Arévalo-López , J. Pilo , H. Muñoz , J.M. Cervantes , L. Huerta , J.E. Antonio , R. Valerio-Méndez , J. Vargas-Bustamante , E. Benitez-Flores , Claire Minaud , C. Cosio-Castañeda , R. Escamilla , M. Romero
In this work, the solid solution of the double spinel LiFe1-xGaxCr4O8 was synthesized and characterized by X-ray diffraction, magnetic susceptibility measurements, UV–Vis–NIR spectroscopy, and X-ray photoelectron spectroscopy (XPS). Rietveld refinements show that the crystal structure is cubic with space group F 3m (No. 216), which is maintained as Fe is gradually substituted by Ga. The lattice parameter a and unit cell volume V decrease consistently due to the smaller ionic radius of Ga compared to Fe. Magnetic susceptibility data indicate that increasing Ga content reduces ferrimagnetic behavior while enhancing the antiferromagnetic component. From Density Functional Theory (DFT) calculations and using Hubbard-corrected Local Spin Density Approximation (LSDA + U) we observe that LiGaCr4O8 has a direct electronic band gap (Eg) of 1.73 eV at the Γ point. Additionally, UV–Vis–NIR spectroscopy reveals an increasing of the direct optical band gap (Eg) with increasing Ga concentration, from 1.43 eV at x = 0.25–1.54 eV at x = 1.00. XPS analysis of Li 1s, Fe 3p, Ga 3d, Cr 3p, and O 1s core levels, together with the valence band (VB), reveals through detailed spectral deconvolution that the oxidation states of Li1+, Fe3+, Ga3+, and Cr3+ remain constant throughout the solid solution.
{"title":"Magnetic and electronic properties of LiFe1-xGaxCr4O8 double spinel by Ga doping","authors":"E.P. Arévalo-López , J. Pilo , H. Muñoz , J.M. Cervantes , L. Huerta , J.E. Antonio , R. Valerio-Méndez , J. Vargas-Bustamante , E. Benitez-Flores , Claire Minaud , C. Cosio-Castañeda , R. Escamilla , M. Romero","doi":"10.1016/j.solidstatesciences.2025.108129","DOIUrl":"10.1016/j.solidstatesciences.2025.108129","url":null,"abstract":"<div><div>In this work, the solid solution of the double spinel LiFe<sub>1-x</sub>Ga<sub>x</sub>Cr<sub>4</sub>O<sub>8</sub> was synthesized and characterized by X-ray diffraction, magnetic susceptibility measurements, UV–Vis–NIR spectroscopy, and X-ray photoelectron spectroscopy (XPS). Rietveld refinements show that the crystal structure is cubic with space group F <span><math><mrow><mover><mn>4</mn><mo>‾</mo></mover></mrow></math></span> 3m (No. 216), which is maintained as Fe is gradually substituted by Ga. The lattice parameter <em>a</em> and unit cell volume <em>V</em> decrease consistently due to the smaller ionic radius of Ga compared to Fe. Magnetic susceptibility data indicate that increasing Ga content reduces ferrimagnetic behavior while enhancing the antiferromagnetic component. From Density Functional Theory (DFT) calculations and using Hubbard-corrected Local Spin Density Approximation (LSDA + U) we observe that LiGaCr<sub>4</sub>O<sub>8</sub> has a direct electronic band gap (E<sub>g</sub>) of 1.73 eV at the Γ point. Additionally, UV–Vis–NIR spectroscopy reveals an increasing of the direct optical band gap (E<sub>g</sub>) with increasing Ga concentration, from 1.43 eV at <em>x</em> = 0.25–1.54 eV at <em>x</em> = 1.00. XPS analysis of Li <em>1s</em>, Fe <em>3p</em>, Ga <em>3d</em>, Cr <em>3p</em>, and O <em>1s</em> core levels, together with the valence band (VB), reveals through detailed spectral deconvolution that the oxidation states of Li<sup>1+</sup>, Fe<sup>3+</sup>, Ga<sup>3+</sup>, and Cr<sup>3+</sup> remain constant throughout the solid solution.</div></div>","PeriodicalId":432,"journal":{"name":"Solid State Sciences","volume":"170 ","pages":"Article 108129"},"PeriodicalIF":3.3,"publicationDate":"2025-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145463972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-03DOI: 10.1016/j.solidstatesciences.2025.108109
Bin He , Haihua Hu , Xiaolong Feng , Claudia Felser
Bi-Sb based topological insulators garnered significant research interest due to their role as a platform for investigating the topological surfaces states and achieving a high thermoelectric figure of merit at and below room temperature. However, electronic transport measurements yield contradictory results, particularly above nitrogen temperature. While zero-field transport exhibits a clear two-carrier signature, field-dependent transport reveals only a single-carrier signature. In this study, we systematically investigated the temperature and field dependent transport properties of Bi88Sb12 including p-type doped crystals. A distinct p-n transition is observed above 60 K, with the crystals exhibiting n-type behavior above 100 K regardless of doping. We propose that Bi88Sb12 is intrinsically close to an n-type semiconductor, a characteristic attributed to heavy T-holes that induce an asymmetric electronic structure between the conduction and valence bands.
{"title":"The influence of heavy valence band in Bi88Sb12","authors":"Bin He , Haihua Hu , Xiaolong Feng , Claudia Felser","doi":"10.1016/j.solidstatesciences.2025.108109","DOIUrl":"10.1016/j.solidstatesciences.2025.108109","url":null,"abstract":"<div><div>Bi-Sb based topological insulators garnered significant research interest due to their role as a platform for investigating the topological surfaces states and achieving a high thermoelectric figure of merit at and below room temperature. However, electronic transport measurements yield contradictory results, particularly above nitrogen temperature. While zero-field transport exhibits a clear two-carrier signature, field-dependent transport reveals only a single-carrier signature. In this study, we systematically investigated the temperature and field dependent transport properties of Bi<sub>88</sub>Sb<sub>12</sub> including <em>p</em>-type doped crystals. A distinct <em>p-n</em> transition is observed above 60 K, with the crystals exhibiting <em>n</em>-type behavior above 100 K regardless of doping. We propose that Bi<sub>88</sub>Sb<sub>12</sub> is intrinsically close to an <em>n</em>-type semiconductor, a characteristic attributed to heavy T-holes that induce an asymmetric electronic structure between the conduction and valence bands.</div></div>","PeriodicalId":432,"journal":{"name":"Solid State Sciences","volume":"170 ","pages":"Article 108109"},"PeriodicalIF":3.3,"publicationDate":"2025-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145517383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-01DOI: 10.1016/j.solidstatesciences.2025.108009
F.F. Alharbi , Salma Aman , Naseeb Ahmad , Muhammad Abdullah , Abdul Ghafoor Abid , Sumaira Manzoor , Sergei Trukhanov , M.I. Sayyed , Daria Tishkevich , Alex Trukhanov
{"title":"Corrigendum to ‘Investigation of photoreduction of Cr (VI) and electrocatalytic properties of hydrothermally produced novel CoFe2O4/ZnO nanostructure’ [Solid State Sci. Volume 143, September 2023, 107278]","authors":"F.F. Alharbi , Salma Aman , Naseeb Ahmad , Muhammad Abdullah , Abdul Ghafoor Abid , Sumaira Manzoor , Sergei Trukhanov , M.I. Sayyed , Daria Tishkevich , Alex Trukhanov","doi":"10.1016/j.solidstatesciences.2025.108009","DOIUrl":"10.1016/j.solidstatesciences.2025.108009","url":null,"abstract":"","PeriodicalId":432,"journal":{"name":"Solid State Sciences","volume":"169 ","pages":"Article 108009"},"PeriodicalIF":3.3,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145412530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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