Electrical Transport — Dielectric relaxation processes, electronic structure, and band gap engineering of MFU-4-type metal-organic frameworks: Towards a rational design of semiconducting microporous materials

3 measurement groups · 11 results

Reported values remain attached to the sample, method, conditions, extraction quality and source location that produced them.

Dielectric spectroscopy-derived real conductivity and Arrhenius analysis

Electrical conductivity Impedance spectroscopy

Co-MFU-4 powder heated at 280 C under vacuum · Powder

MFU-4 heated at 280 C and Co-MFU-4 compared at several frequencies; 0.01 Hz used as dc estimate at high temperature.

Temperature: about 300-600
Atmosphere: vacuum pretreated
Geometry: powder-filled parallel-plate capacitor
Context: pristine Co-MFU-4 compared against pristine MFU-4
Measurement source: p006 · Electrical Conductivity and Charge Transport · Fig. 8

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Co-MFU-4 conductivity relative to MFU-4	significantly higher than for the pure sample	—	—	Qualitative Qualitative	p006 · Electrical Conductivity and Charge Transport · Fig. 8a
Co-MFU-4 conductivity activation energyMarked as a best value within this paper	1.8 eV	—	—	Text Exact Reported	p006 · Electrical Conductivity and Charge Transport · Fig. 8b
Co-MFU-4 dc conductivity order at 400 KMarked as a best value within this paper	order of 10^-14 ohm^-1 cm^-1 at 400 K	—	order of	Text Approximate	p010 · Conclusion · Fig. 8
MFU-4 conductivity activation energy / band-conduction barrierMarked as a best value within this paper	2.9 eV	—	—	Text Exact Reported	p006 · Electrical Conductivity and Charge Transport · Fig. 8b
MFU-4 dc conductivity order at 480 KMarked as a best value within this paper	order of 10^-14 ohm^-1 cm^-1 at 480 K	—	order of	Text Approximate	p010 · Conclusion · Fig. 8

Broadband dielectric spectroscopy with parallel-plate capacitor and Novocontrol alpha-Analyzer

Impedance spectroscopy

MFU-4 powder heated at 280 C under vacuum · Powder

Powder sample, slight pressure in Teflon-ring capacitor; vacuum 48 h before each run; 0.01 Hz <= nu <= 620 kHz; 10-600 K using closed-cycle refrigerator and oven.

Temperature: 10-600
Atmosphere: vacuum pretreatment; measurement atmosphere not fully specified
Geometry: powder-filled parallel-plate capacitor
Context: activated MFU-4 with possible minor residual DMF
Measurement source: p011 · Experimental Section, Dielectric Spectroscopy · Fig. 3-Fig. 6

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Low-temperature dielectric constant epsilon primeMarked as a best value within this paper	of the order of 2 and nearly temperature and frequency independent (less than 10% variation)	—	order of; <10% variation	Text Approximate	p003 · Relaxation Dynamics · Fig. 3
Relaxation process I activation energyMarked as a best value within this paper	0.40 eV	—	—	Text Exact Reported	p004 · Relaxation Dynamics · Fig. 6
Relaxation process I peak temperatures	199, 151, and 126 K	—	—	Text Exact Reported	p004 · Relaxation Dynamics · Fig. 4
Relaxation process II activation energyMarked as a best value within this paper	0.13 eV	—	—	Text Exact Reported	p004 · Relaxation Dynamics · Fig. 6
Relaxation process III activation energyMarked as a best value within this paper	0.060 eV	—	—	Text Exact Reported	p004 · Relaxation Dynamics · Fig. 6

Broadband dielectric spectroscopy comparison of as-prepared, 280 C activated, and 320 C activated MFU-4

Impedance spectroscopy

As-prepared DMF-loaded MFU-4 powder · Powder

Dielectric constant/loss compared below 300 K at selected frequencies for different DMF contents.

Temperature: <300
Atmosphere: vacuum pretreatment for activated samples
Geometry: powder-filled parallel-plate capacitor
Context: DMF-loaded MFU-4 compared with activated MFU-4 controls
Measurement source: p004 · Relaxation Dynamics · Fig. 5

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Process I amplitude after 280 C and 320 C activationMarked as a best value within this paper	Process I amplitude reduced by about factor 10 at 280 C and completely suppressed at 320 C	—	about	Text Approximate	p004 · Relaxation Dynamics · Fig. 5