scholarly journals Single Crystals of Electrically Conductive 2D MOFs: Structural and Electrical Transport Properties

2019 ◽  
Author(s):  
Robert W. Day ◽  
D. Kwabena Diako ◽  
Mehdi Rezaee ◽  
Lucas R. Parent ◽  
Grigorii Skorupskii ◽  
...  
Keyword(s):  
Single Crystal ◽  
Single Crystals ◽  
Electrical Transport ◽  
Prolonged Exposure ◽  
Metal Organic Frameworks ◽  
Two Dimensions ◽  
Conductivity Measurements ◽  
Electrical Transport Properties ◽  
Electrically Conductive ◽  
Metal Organic

Crystalline, electrically conductive, and intrinsically porous materials are rare. Layered 2D metal-organic frameworks (MOFs) break this trend. They are porous crystals that exhibit high electrical conductivity and are novel platforms for studying fundamentals of electricity and magnetism in two dimensions.1-8 Despite demonstrated applications,9-13 electrical transport in these remains poorly understood because of a lack of single crystal studies. Here, studies of single crystals of two 2D MOFs, Ni3(HITP)2 and Cu3(HHTP)2, uncover critical insights into their structure and transport. Conductivity measurements down to 0.3 K suggest metallicity for mesoscopic single crystals of Ni3(HITP)2, which contrasts with apparent activated conductivity for polycrystalline films. Microscopy studies further reveal that these MOFs are not isostructural as previously reported.14 Notably, single rods exhibit conductivities up to 150 S/cm, which persist even after prolonged exposure to the ambient. These single crystal studies confirm that 2D MOFs hold promise as molecularly tunable platforms for fundamental science and applications where porosity and conductivity are critical.<br>

scholarly journals Single Crystals of Electrically Conductive 2D MOFs: Structural and Electrical Transport Properties

2019 ◽  
Author(s):  
Robert W. Day ◽  
D. Kwabena Diako ◽  
Mehdi Rezaee ◽  
Lucas R. Parent ◽  
Grigorii Skorupskii ◽  
...  
Keyword(s):  
Single Crystal ◽  
Single Crystals ◽  
Electrical Transport ◽  
Prolonged Exposure ◽  
Metal Organic Frameworks ◽  
Two Dimensions ◽  
Conductivity Measurements ◽  
Electrical Transport Properties ◽  
Electrically Conductive ◽  
Metal Organic

Crystalline, electrically conductive, and intrinsically porous materials are rare. Layered 2D metal-organic frameworks (MOFs) break this trend. They are porous crystals that exhibit high electrical conductivity and are novel platforms for studying fundamentals of electricity and magnetism in two dimensions.1-8 Despite demonstrated applications,9-13 electrical transport in these remains poorly understood because of a lack of single crystal studies. Here, studies of single crystals of two 2D MOFs, Ni3(HITP)2 and Cu3(HHTP)2, uncover critical insights into their structure and transport. Conductivity measurements down to 0.3 K suggest metallicity for mesoscopic single crystals of Ni3(HITP)2, which contrasts with apparent activated conductivity for polycrystalline films. Microscopy studies further reveal that these MOFs are not isostructural as previously reported.14 Notably, single rods exhibit conductivities up to 150 S/cm, which persist even after prolonged exposure to the ambient. These single crystal studies confirm that 2D MOFs hold promise as molecularly tunable platforms for fundamental science and applications where porosity and conductivity are critical.<br>

Electrical Transport Properties of the Pentatelluride Materials Hfte5 and Zrte5

1997 ◽  
Vol 478 ◽  
Author(s):  
T. M. Tritt ◽  
M. L. Wilson ◽  
R. L. Littleton ◽  
C. Feger ◽  
J. Kolis ◽  
...  
Keyword(s):  
Single Crystal ◽  
Single Crystals ◽  
Electrical Transport ◽  
Entire Range ◽  
Room Temperature ◽  
Polycrystalline Material ◽  
Polycrystalline Materials ◽  
Electrical Transport Properties ◽  
Low Dimensional ◽  
P Type

AbstractWe have measured the resistivity and thermopower of single crystals as well as polycrystalline pressed powders of the low-dimensional pentatelluride materials: HfTe5 and ZrTe5. We have performed these measurements as a function of temperature between 5K and 320K. In the single crystals there is a peak in the resistivity for both materials at a peak temperature, Tp where Tp ≈ 80K for HfTe5 and Tp ≈ 145K for ZrTe5. Both materials exhibit a large p-type thermopower around room temperature which undergoes a change to n-type below the peak. This data is similar to behavior observed previously in these materials. We have also synthesized pressed powders of polycrystalline pentatelluride materials, HfTe5 and ZrTe5. We have measured the resistivity and thermopower of these polycrystalline materials as a function of temperature between 5K and 320K. For the polycrystalline material, the room temperature thermopower for each of these materials is relatively high, +95 μV/K and +65 μV/K for HfTe5 and ZrTe5 respectively. These values compare closely to thermopower values for single crystals of these materials. At 77 K, the thermopower is +55 μV/K for HfTe5 and +35 μV/K for ZrTe5. In fact, the thermopower for the polycrystals decreases monotonically with temperature to T ≈ 5K, thus exhibiting p-type behavior over the entire range of temperature. As expected, the resistivity for the polycrystals is higher than the single crystal material, with values of 430 mΩ-cm and 24 mΩ-cm for Hfre5 and ZrTe5 respectively, compared to single crystal values of 0.35 mΩ-cm (HfTe5) and 1.0 mΩ-cm (ZrTe5). We have found that the peak in the resistivity evident in both single crystal materials is absent in these polycrystalline materials. We will discuss these materials in relation to their potential as candidates for thermoelectric applications.

scholarly journals Amino acids as highly efficient modulators for single crystals of zirconium and hafnium metal–organic frameworks

2016 ◽  
Vol 4 (18) ◽  
pp. 6955-6963 ◽  
Author(s):  
Ross J. Marshall ◽  
Claire L. Hobday ◽  
Colin F. Murphie ◽  
Sarah L. Griffin ◽  
Carole A. Morrison ◽  
...  
Keyword(s):  
Amino Acids ◽  
Single Crystal ◽  
Single Crystals ◽  
Crystal Structures ◽  
Metal Organic Frameworks ◽  
Single Crystal Structures ◽  
Highly Efficient ◽  
Metal Organic ◽  
P Addition

Addition of small quantities of amino acids to solvothermal and microwave syntheses of Zr and Hf MOFs drastically improves their crystallinity to the extent that single crystal structures can be obtained.

Controlled Growth of the Non-centrosymmetric Zn(3-ptz)2 and Zn(Oh)(3-ptz) Metal-organic Frameworks

2019 ◽  
Author(s):  
javier enriquez ◽  
Ignacio Chi-Duran ◽  
Carolina Manquian ◽  
Felipe Herrera ◽  
Ruben Fritz ◽  
...  
Keyword(s):  
Single Crystal ◽  
Nonlinear Optical ◽  
Metal Organic Frameworks ◽  
Molar Ratio ◽  
Thermal Synthesis ◽  
Small Crystals ◽  
Alkaline Environments ◽  
Potential Applications ◽  
Metal Organic ◽  
Long Rod

Non-centrosymmetric single-crystal metal-organic frameworks (MOF) are promising candidates for phase-matched nonlinear optical communication, but typical hydrothermal synthesis produces small crystals with relatively low transmittance and poor phase matching. We study the effect of the metal-to-ligand molar ratio and reaction pH on the hydro-thermal synthesis of the non-centrosymmetric Zn(3-ptz)<sub>2</sub> and Zn(OH)(3-ptz) MOFs with <i>in-situ </i>ligand formation. In acidic environments, we find that decreasing the amount of ligand below the stoichiometric molar ratio 1:2 also produces highly transparent single-crystal octahedrons of <b>Zn(3-ptz)<sub>2</sub></b>. In alkaline environments, we obtain long rod-like <b>Zn(OH)(3-ptz) </b>crystals whose length exceeds previous reports by up to four orders of magnitude. Potential applications of these results in the development of MOF-based nonlinear optical devices are discussed.

Single crystal to single crystal transformation of spin-crossover coordination polymers from 3D frameworks to 2D layers

2021 ◽  
Vol 9 (15) ◽  
pp. 5082-5087
Author(s):  
Yu Gong ◽  
Wang-Kang Han ◽  
Hui-Shu Lu ◽  
Qing-Tao Hu ◽  
Huan Tu ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Single Crystal ◽  
Coordination Polymers ◽  
Ligand Exchange ◽  
Spin Crossover ◽  
Metal Organic Frameworks ◽  
Crystal Transformation ◽  
Metal Organic

New Hofmann-type metal–organic frameworks display rare and complete ligand exchange induced single crystal to single crystal transformations from 3D frameworks to 2D layers, accompanied by magnetic properties transition from two-step SCO behavior to hysteretic SCO behavior.

Electrical transport properties of FeSe single crystal under high magnetic field

2021 ◽  
Vol 64 (8) ◽  
Author(s):  
HongHui Wang ◽  
ZhaoHui Cheng ◽  
MengZhu Shi ◽  
DongHui Ma ◽  
WeiZhuang Zhuo ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Single Crystal ◽  
Transport Properties ◽  
High Magnetic Field ◽  
Electrical Transport ◽  
Electrical Transport Properties
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