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1. Function Graded Carbon Micro‐Structures for Powerless Photon Sensing with Intriguing µm‐Scale Position Sensitivity

   https://doi.org/10.1002/adom.202301377  

   Karamati, Amin; Qu, Wangda; Bai, Xianglan; Wang, Xinwei (September 2023, Advanced Optical Materials)

   Abstract Partial laser treatment is introduced to carbon‐based microfibers to generate excellent photon sensing capability without bias. This treatment brings about a Seebeck coefficient distribution along the sample's length, out of which a photovoltage with no external bias is generated and sensed. Using a line‐shaped laser spot, carbon microfiber (CMF), graphene microfiber (GMF), and graphene aerogel fiber (GAF) are investigated for their response to µm‐scale photon irradiation. A higher sensitivity for the incident photon is found for the GAF with no position sensitivity. More Seebeck coefficient variation is also observed for the GAF considering the amount of laser power used for the laser treatment. A weaker Seebeck coefficient spatial variation is observed for the GMF compared with the GAF. However, its photovoltage shows an abrupt magnitude change from the laser‐treated region to the non‐treated one. Despite the low spatial variation of the Seebeck coefficient for the CMF, it features an excellent and accurate position‐sensitive photoresponse with polarization change over a distance of ≈100 µm. Such unique capability prompts novel applications in using partially annealed CMF for sensing the position of optical beams at the microscale. 

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2. Ultra-low thermal conductivity and promising thermoelectric performance in the structurally complex Zintl phase: Eu14GaAs11

   https://doi.org/10.1039/D5TA09465H  

   Islam, Md Minhajul; Wróblewska, Maria; Xu, Yixuan; Toberer, Eric S; Kauzlarich, Susan M (March 2026, Journal of Materials Chemistry A)

   New Zintl compound Eu₁₄GaAs₁₁shows ultra-low thermal conductivity and a high Seebeck coefficient due to its complex structure, indicating potential for further optimization to enhance thermoelectric performance. 

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3. Data from: Role of copper doping in modulating the thermoelectric properties of Eu₁₁Zn₄Sn₂As₁₂

   https://doi.org/10.5061/dryad.d7wm37qgk  

   Miramontes, Christopher; Wróblewska, Maria; Toberer, Eric; Kauzlarich, Susan (January 2026, Dryad)

   Abstract: Eu11Zn4Sn2As12 is a p-type semiconductor that has been proposed to undergo 3D-to-2D electronic transport as the carrier concentration increases. This commensurately modulated structure in space group R3̅m has been shown to improve its thermoelectric properties upon Na doping, concurrently decreasing electrical resistivity while maintaining a large Seebeck coefficient. In this study, Eu11Zn4Sn2As12 was doped with Cu with the goal of substituting in the [Zn2As3]5− defect hexagonal layers to improve electrical transport. Thermal conductivity, carrier concentration, mobility, electrical resistivity, and the Seebeck coefficients as a function of temperature from 300 to 600 K were measured as a function of Cu content. A maximum zT600K of 0.24 for Eu11Zn4-xCuxSn2As12, x = 0.6, was reached. Methods: The samples, Eu₁₁Zn_4-xCuxSn2As₁₂ (x = 0.0, 0.2, 0.4, 0.6) were synthesized and analyzed by powder X-ray diffraction and pressed into dense pellets by Spark Plasma Sintering. The pellets were ≥ 98 % dense by the Archimedes method. Scanning electron microscopy (SEM) and energy-dispersive spectroscopy were obtained and provided in the publication's supporting information. Thermal conductivity, carrier concentration, mobility, electrical resistivity, and the Seebeck coefficients were collected as a function of temperature from 300 to 600 K. Powder X-Ray Diffraction: The sintered sample pellets were ground in a mortar and pestle for PXRD analysis. Samples were plated onto a zero-background X-ray quartz plate, and diffraction was performed with a Bruker D8 Advance Eco diffractometer with Cu Kα radiation (λ = 1.5405 Å) at 40 kV and 25 mA at room temperature. Data was collected with a 0.01 step size and a 2θ range from 20° - 80°. Thermal Conductivity: A Netzsch Laser Flash Analysis (LFA) 475 Microflash instrument was used to measure the thermal diffusivity of the pellets (polished flat and parallel and sprayed with graphite to ensure laser absorption). Thermal conductivity was calculated using thermal diffusivity using the equation κ = λδCp, where κ is thermal conductivity, λ is thermal diffusivity, δ is the sample density, and Cp is the Dulong-Petit heat capacity. Seebeck, Resistivity, and Hall Measurement: Seebeck coefficient measurements were obtained from a custom-built instrument under nitrogen atmosphere and pressure of 300 Torr from 300 to 600K. Resistivity and Hall measurements were obtained with an in-house-built instrument using the van der Pauw geometry. Hall coefficient measurements used 80 mA current and 1 T magnetic field. TechnicalInfo: # Data from: Role of copper doping in modulating the thermoelectric properties of Eu~11~Zn~4~Sn~2~As~12~ Dataset DOI: [10.5061/dryad.d7wm37qgk](https://doi.org/10.5061/dryad.d7wm37qgk) ## Description of the data and file structure The folder entitled Eu11Zn4Sn2As12_Cu_Doping.zip contains 4 *.csv* files, one for each composition of Eu~11~Zn~4−x~*Cu~x~Sn~2~As~12~ (*x* = 0.0, 0.2, 0.4, 0.6) The data are provided in column with room Temperature powder X-ray diffraction, electrical resistivity as a function of temperature (300-600 K), Seebeck coefficients as a function of temperature (300-600 K), thermal conductivity as a function of temperature (300-600 K), carrier concentration as a function of temperature (300-600 K), and Hall mobility as a function of temperature (300-600 K). #### Folder: Eu11Zn4Sn2As12_Cu_Doping.zip **Description:** Contains 4 *.csv files: * Eu11Zn4-xCuxSn2As12_x=0 * Eu11Zn4-xCuxSn2As12_x=0.2 * Eu11Zn4-xCuxSn2As12_x=0.4 * Eu11Zn4-xCuxSn2As12_x=0.6 ## Files and variables File: Eu11Eu4-xCuxSn2As12_x=0.0\ Room temperature powder X-ray diffraction (PXRD) data are provided in columns A and B, with two-theta/degree (column A) and intensity/arbitrary units (au) (column B). Column C is empty. Resistivity vs Temperature data are provided in columns D and E), with Temperature/K (column D) and resistivity/mOhm cm (column E). Column F is empty. Seebeck coefficient vs Temperature data is provided in Columns G and H, with Temperature/K and Seebeck coefficient/µV/K. Column I is empty. Thermal conductivity vs Temperature data are provided in columns J and K, with Temperature/K (column J) and thermal conductivity/W/m K (column K). Column L is empty. Carrier concentration vs Temperature data are found in columns M and N, with Temperature/K (column M) and carrier concentration/h^+^ cm ^-3^ (column N). Hall mobility vs Temperature is provided in columns O and P, with Temperature/K (column O) and Hall mobility/cm^2^ V ^-1^ s ^-1^ (column P). File: Eu11Eu4-xCuxSn2As12_x=0.2\ Room temperature powder X-ray diffraction (PXRD) data are provided in columns A and B, with two-theta/degree (column A) and intensity/arbitrary units (au) (column B). Column C is empty. Resistivity vs Temperature data are provided in columns D and E), with Temperature/K (column D) and resistivity/mOhm cm (column E). Column F is empty. Seebeck coefficient vs Temperature data (measured twice to show reproducibiity) is provided in Columns G-J, with Temperature/K and Seebeck coefficient/µV/K. Column K is empty. Thermal conductivity vs Temperature data are provided in columns L and M, with Temperature/K (column L) and thermal conductivity/W/m K (column M). Column N is empty. Carrier concentration vs Temperature data are found in columns O and P, with Temperature/K (column O) and carrier concentration/h^+^ cm ^-3^ (column P). Hall mobility vs Temperature is provided in columns Q and R, with Temperature/K (column Q) and Hall mobility/cm^2^ V ^-1^ s ^-1^ (column R). File: Eu11Zn4-xCuxSn2As12_x=0.4\ Room temperature powder X-ray diffraction (PXRD) data are provided in columns A and B, with two-theta/degree (column A) and intensity/arbitrary units (au) (column B). Column C is empty. Resistivity vs Temperature data are provided in columns D and E), with Temperature/K (column D) and resistivity/mOhm cm (column E). Column F is empty. Seebeck coefficient vs Temperature data (measured twice to show reproducibiity) is provided in Columns G-J, with Temperature/K and Seebeck coefficient/µV/K. Column K is empty. Thermal conductivity vs Temperature data are provided in columns L and M, with Temperature/K (column L) and thermal conductivity/W/m K (column M). Column N is empty. Carrier concentration vs Temperature data are found in columns O and P, with Temperature/K (column O) and carrier concentration/h^+^ cm ^-3^ (column P). Hall mobility vs Temperature is provided in columns Q and R, with Temperature/K (column Q) and Hall mobility/cm^2^ V ^-1^ s ^-1^ (column R). File: Eu11Zn4-xCuxSn2As12_x=0.6\ Room temperature powder X-ray diffraction (PXRD) data are provided in columns A and B, with two-theta/degree (column A) and intensity/arbitrary units (au) (column B). Column C is empty. Resistivity vs Temperature data are provided in columns D and E), with Temperature/K (column D) and resistivity/mOhm cm (column E). Column F is empty. Seebeck coefficient vs Temperature data is provided in Columns G and H, with Temperature/K and Seebeck coefficient/µV/K. Column I is empty. Thermal conductivity vs Temperature data are provided in columns J and K, with Temperature/K (column J) and thermal conductivity/W/m K (column K). Column L is empty. Carrier concentration vs Temperature data are found in columns M and N, with Temperature/K (column M) and carrier concentration/h^+^ cm ^-3^ (column N). Hall mobility vs Temperature is provided in columns O and P, with Temperature/K (column O) and Hall mobility/cm^2^ V ^-1^ s ^-1^ (column P). 

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4. Examining the electron transport in chalcogenide perovskite BaZrS ₃

   https://doi.org/10.1039/d1tc00374g  

   Osei-Agyemang, Eric; Koratkar, Nikhil; Balasubramanian, Ganesh (March 2021, Journal of Materials Chemistry C)

   null (Ed.)

   Orthorhombic BaZrS 3 is a potential optoelectronic material with prospective applications in photovoltaic and thermoelectric devices. While efforts exist on understanding the effects of elemental substitution and material stability, fundamental knowledge on the electronic transport properties are sparse. We employ first principles calculations to examine the electronic band structure and optical band gap and interrogate the effect of electron transport on electrical and thermal conductivities, and Seebeck coefficient, as a function of temperature and chemical potential. Our results reveal that BaZrS 3 has a band gap of 1.79 eV in proximity of the optimal 1.35 eV recommended for single junction photovoltaics. An absorption coefficient of 3 × 10 5 cm −1 at photon energies of 3 eV is coupled with an early onset to optical absorption at 0.5 eV, significantly below the optical band gap. The carrier effective mass being lower for electrons than holes, we find the Seebeck coefficient to be higher for holes than electrons. A notable (≈1.0 at 300 K) upper limit to the thermoelectric figure of merit, obtained due to high Seebeck coefficient (3000 μV K −1 ) and ultra-low electron thermal conductivity, builds promise for BaZrS 3 as a thermoelectric. 

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5. Apparatus for the room temperature measurement of low field Nernst and magneto-Seebeck coefficients

   https://doi.org/10.1063/5.0222406  

   Porter, C E; Crawford, C M; Toberer, E S (August 2024, Review of Scientific Instruments)

   Nernst coefficient measurements are a classic approach to investigate charge carrier scattering in both metals and semiconductors. However, such measurements are not commonly performed, despite the potential to inform material design strategies in applications such as thermoelectricity. As dedicated instruments are extremely scarce, we present here a room temperature apparatus to measure the low field Nernst coefficient (and magneto-Seebeck coefficient) in bulk polycrystalline samples. This apparatus is specifically designed to promote accurate and facile use, with the expectation that such an instrument will make Nernst measurements de rigueur. In this apparatus, sample loading and electrical contacts are all pressure-based and alignment is automatic. Extremely stable thermal control (10 mK of fluctuation when ΔT = 1 K) is achieved from actively cooled thermoelectric modules that operate as heaters or Peltier coolers. Magneto-Seebeck measurements are integrated into the system to correct for residual probe offsets. Data from the apparatus are provided on bulk polycrystalline samples of bismuth, InSb, and SnTe, including raw data to illustrate the process of calculating the Nernst coefficient. Finally, we review how Nernst measurements, in concert with Seebeck, Hall, and electrical resistivity, can be analyzed via the Boltzmann equation in the relaxation time approximation to self-consistently predict the Fermi level, effective mass, and energy-dependent relaxation time. 

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