Sensing Application — Sensitive humidity sensors based on ionically conductive metal-organic frameworks for breath monitoring and non-contact sensing

12 measurement groups · 42 results

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

Breath monitoring, word recognition, and non-contact hand humidity tests

IC-Mg2(dobdc) humidity sensor · Electrode

Mouth breathing at 10-30 cm; speech words big/medium/small; dry hand moved to 5 cm, 2 cm, 1 cm, and 5 mm.

Atmosphere: Ambient with local humidity perturbations from breath or hand
Geometry: IC-Mg2(dobdc) thin-film humidity sensor
Context: Pristine Mg2(dobdc) IC-MOF film
Measurement source: main p.5-7, article pp.5-7 · Results and discussion · Fig. 5a-f

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Shallow exhalation low capacitance	about 0.5 nF	—	—	Text Approximate	main p.5, article p.5 · Results and discussion · Fig. 5b
Shallow exhalation peak capacitance	about 2-3 nF	—	range 2-3 nF	Text Range	main p.5, article p.5 · Results and discussion · Fig. 5b
Non-contact hand distance set	5 cm, 2 cm, 1 cm, and 5 mm	—	—	Caption Exact Reported	main p.7, article p.7 · Figure caption · Fig. 5f
Speech stimulus big capacitance	400 pF	—	—	Text Rounded Reported	main p.6, article p.6 · Results and discussion · Fig. 5d
Speech stimulus medium capacitance	1 nF	—	—	Text Rounded Reported	main p.6, article p.6 · Results and discussion · Fig. 5d
Speech stimulus small capacitanceMarked as a best value within this paper	as high as 3 nF	—	—	Text Approximate	main p.6, article p.6 · Results and discussion · Fig. 5d

Flexible-sensor non-contact skin humidity, nose breathing, water spraying, and bending tests

Flexible IC-MOF humidity sensor on PEN · Electrode

PEN-based sensor tested with hand humidity at 2 cm, nose breathing on mask, atomized water at 30 cm, and manual bending 100-300 times.

Atmosphere: Ambient; 36%, 40%, and 43% RH for bending comparison
Geometry: Flexible IC-MOF humidity sensor on PEN
Context: Pristine Mg2(dobdc) IC-MOF film on flexible PEN substrate
Measurement source: main p.7-8, article pp.7-8 · Results and discussion · Fig. 6a-i, Figure S19

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Flexible sensor bending durability	maintained at different humidity levels throughout over 300 bending cycles	—	—	Text Rounded Reported	main p.8, article p.8 · Results and discussion · Fig. 6g-i
Dry hand without gloves response	10 to 200 pF	—	range 10-200 pF	Text Range	main p.7, article p.7 · Results and discussion · Fig. 6c
Moist hand with gloves response	Capacitance value did not change	—	—	Text Qualitative	main p.7, article p.7 · Results and discussion · Fig. 6c
Moist hand without gloves responseMarked as a best value within this paper	1.2 nF	—	—	Text Exact Reported	main p.7, article p.7 · Results and discussion · Fig. 6c
Flexible sensor spraying recovery time	5.5 s	—	—	Text Exact Reported	main p.8, article p.8 · Results and discussion · Figure S19c
Flexible sensor spraying response time	4.5 s	—	—	Text Exact Reported	main p.8, article p.8 · Results and discussion · Figure S19c
Water-spraying capacitance test 1	11.3 nF	—	—	Text Exact Reported	main p.8, article p.8 · Results and discussion · Figure S19b
Water-spraying capacitance test 2	11.3 nF	—	—	Text Exact Reported	main p.8, article p.8 · Results and discussion · Figure S19b
Water-spraying capacitance test 3	10.3 nF	—	—	Text Exact Reported	main p.8, article p.8 · Results and discussion · Figure S19b

Capacitive humidity response comparison

Mg2(dobdc)-MOF humidity sensor without free metal ions · Electrode

Switching between 2% and 4% RH for Mg-MOF sensors with and without free metal ions.

Atmosphere: 2% and 4% RH
Geometry: Thin-film humidity sensor
Context: Control without free metal ions compared against IC-Mg2(dobdc) with free ions
Measurement source: main p.3, article p.3 · Results and discussion · Fig. 2c

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
No-free-ion control response	Cannot distinguish humidity between 2% and 4% RH	—	—	Text Qualitative	main p.3, article p.3 · Results and discussion · Fig. 2c

Capacitive humidity sensing with TH2827C Precision LCR meter

IC-MOF thin-film humidity sensor series on conductive glass · Electrode

400 Hz and 1 V; RH generated by nitrogen, drying agents, and saturated salt solutions from near 0% to 97% RH.

Atmosphere: N2 or sealed bottles with drying agent/saturated salt solutions
Geometry: IC-MOF film on ITO/glass interdigital electrode
Context: Pristine IC-MOF thin-film sensors
Measurement source: main p.2, article p.2 · 2.4. Sensing experiments · Figure S1

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Selected sensor operating frequency	400 Hz	—	—	Text Exact Reported	main p.2-3, article pp.2-3 · 2.4. Sensing experiments; Results · Figure S12
Selected sensor operating voltage	1 V	—	—	Text Exact Reported	main p.2, article p.2 · 2.4. Sensing experiments

Capacitive response curves for Mg-ligand series

IC-MOF thin-film humidity sensor series on conductive glass · Electrode

Mg2(dobdc), Mg2PMA, and Mg2PTA sensors switched between 43%, 61%, and 84% RH at 400 Hz.

Atmosphere: 43%, 61%, and 84% RH
Geometry: Thin-film humidity sensors on ITO/glass
Context: Pristine Mg IC-MOF ligand comparison series
Measurement source: main p.3, article p.3 · Results and discussion · Fig. 3b

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Best Mg-ligand sensorMarked as a best value within this paper	IC-Mg2(dobdc) shows better humidity sensing performance than Mg2PMA and Mg2PTA	—	—	Text Qualitative	main p.3, article p.3 · Results and discussion · Fig. 3b

Capacitive response curves for metal-ion series

IC-MOF thin-film humidity sensor series on conductive glass · Electrode

M2(dobdc)-MOF sensors (M = Mg, Co, Cu, Zn, Ni) switched between 43%, 61%, and 84% RH at 400 Hz.

Atmosphere: 43%, 61%, and 84% RH
Geometry: Thin-film humidity sensors on ITO/glass
Context: Pristine IC-MOF metal-centre comparison series
Measurement source: main p.3, article p.3 · Results and discussion · Fig. 3a

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
IC-Co2(dobdc) capacitance at 84% RH	about 4 nF	—	—	Text Approximate	main p.3, article p.3 · Results and discussion · Fig. 3a
IC-Mg2(dobdc) capacitance at 84% RHMarked as a best value within this paper	about 11 nF	—	—	Text Approximate	main p.3, article p.3 · Results and discussion · Fig. 3a
Other IC-MOF capacitance at 84% RH	about 1 nF	—	—	Text Approximate	main p.3, article p.3 · Results and discussion · Fig. 3a

Dynamic capacitance response over RH series

IC-Mg2(dobdc) humidity sensor · Electrode

Near 0% to 97% RH at 400 Hz and 1 V.

Atmosphere: Near 0%, 2%, 4%, 7%, 12%, 24%, 36%, 43%, 61%, 75%, 84%, and 97% RH
Geometry: IC-Mg2(dobdc) thin-film humidity sensor
Context: Pristine Mg2(dobdc) IC-MOF film
Measurement source: main p.3, article p.3 · Results and discussion · Fig. 3c-d

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Capacitance at 97% RHMarked as a best value within this paper	12,210 pF	—	—	Text Exact Reported	main p.3, article p.3 · Results and discussion · Fig. 3c
Capacitance near 0% RH	7 pF	—	—	Text Exact Reported	main p.3, article p.3 · Results and discussion · Fig. 3c
Lower RH detection condition	close to 0% RH	—	—	Text Approximate	main p.3, article p.3 · Results and discussion · Fig. 3c
Upper RH detection conditionMarked as a best value within this paper	97% RH	—	—	Text Exact Reported	main p.3, article p.3 · Results and discussion · Fig. 3c
Sensitivity over 0-12% RH	36 per 1% RH	—	—	Text Exact Reported	main p.3, article p.3 · Results and discussion · Figure S13
Sensitivity over 12-43% RH	477 per 1% RH	—	—	Text Exact Reported	main p.3, article p.3 · Results and discussion · Figure S13
Sensitivity over 36-61% RHMarked as a best value within this paper	4237 per 1% RH	—	—	Text Exact Reported	main p.3, article p.3 · Results and discussion · Figure S13
Sensitivity over 75-97% RH	1537 per 1% RH	—	—	Text Exact Reported	main p.3, article p.3 · Results and discussion · Figure S13

Adsorption/desorption humidity hysteresis

IC-Mg2(dobdc) humidity sensor · Electrode

Adsorption varying RH from 0% to 97%; desorption varying RH from 97% to 0%.

Atmosphere: 0-97% RH adsorption/desorption
Geometry: IC-Mg2(dobdc) thin-film humidity sensor
Context: Pristine Mg2(dobdc) IC-MOF film
Measurement source: main p.5, article p.5 · Results and discussion · Fig. 3e

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Maximum hysteresis	8.8% RH at 61% RH	—	—	Text Exact Reported	main p.5, article p.5 · Results and discussion · Fig. 3e

Response/recovery time tests

IC-Mg2(dobdc) humidity sensor · Electrode

Bottle-to-bottle 2-97% RH and bottle-to-atmosphere 12-58% RH tests.

Atmosphere: 2%, 12%, 58%, and 97% RH conditions
Geometry: IC-Mg2(dobdc) thin-film humidity sensor
Context: Pristine Mg2(dobdc) IC-MOF film
Measurement source: main p.5, article p.5 · Results and discussion · Fig. 4a-c, Table 1, Figure S14

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Recovery time for 12-58% RH switchingMarked as a best value within this paper	1.5 s	—	—	Text Exact Reported	main p.5, article p.5 · Results and discussion · Fig. 4b, Table 1
Recovery time for 2-97% RH switching	2 s	—	—	Text Exact Reported	main p.5, article p.5 · Results and discussion · Figure S14
Response time for 12-58% RH switchingMarked as a best value within this paper	2.5 s	—	—	Text Exact Reported	main p.5, article p.5 · Results and discussion · Fig. 4b, Table 1
Response time for 2-97% RH switching	13.5 s	—	—	Text Exact Reported	main p.5, article p.5 · Results and discussion · Figure S14

Working repeatability and long-term stability tests

IC-Mg2(dobdc) humidity sensor · Electrode

Eight cycles under 12%, 36%, 61%, 75%, and 97% RH; storage and operation under 2%, 58%, and 97% RH; 6-month air storage.

Atmosphere: 2%, 12%, 36%, 58%, 61%, 75%, and 97% RH; ambient air storage
Geometry: IC-Mg2(dobdc) thin-film humidity sensor
Context: Pristine Mg2(dobdc) IC-MOF film
Measurement source: main p.5, article p.5 · Results and discussion · Fig. 4d-e, Figures S15-S17

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Working repeatability cycles	eight cycles under 12%, 36%, 61%, 75%, and 97% RH	—	—	Text Exact Reported	main p.5, article p.5 · Results and discussion · Fig. 4d
Long-term stability at 2% RH	120 h at 2% RH with good operating characteristics	—	—	Text Exact Reported	main p.5, article p.5 · Results and discussion · Fig. 4e
Long-term stability at 58% RH	12 h continuous test at 58% RH with capacitance basically unchanged	—	—	Text Exact Reported	main p.5, article p.5 · Results and discussion · Figure S15
Long-term stability tests at 97% RH	1-hour testing on the first, third and fifth day at 97% RH	—	—	Text Exact Reported	main p.5, article p.5 · Results and discussion · Figure S16
Environmental air storage stability	6 months in air without encapsulation; decent response and recovery curves retained	—	—	Text Exact Reported	main p.5, article p.5 · Results and discussion · Figure S17

Real-time mobile humidity monitoring system

IC-Mg2(dobdc) humidity sensor · Electrode

Signal conditioner, signal processor, Bluetooth, mobile application; mouth-breathing demonstration.

Atmosphere: Ambient with mouth-breathing perturbation
Geometry: IC-Mg2(dobdc) sensor connected with 20 pF series capacitor for readout
Context: Pristine Mg2(dobdc) IC-MOF film
Measurement source: main p.7, article p.7 · Results and discussion · Fig. 5g-h

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Series capacitor for mobile readout	20 pF	—	—	Text Exact Reported	main p.7, article p.7 · Results and discussion · Fig. 5g-h

Humidity sensor response at different temperatures

IC-Mg2(dobdc) humidity sensor · Electrode

Capacitance response compared at 5, 15, and 30 deg C.

Temperature: 278.15; 288.15; 303.15
Atmosphere: Different RH conditions
Geometry: IC-Mg2(dobdc) thin-film humidity sensor
Context: Pristine Mg2(dobdc) IC-MOF film
Measurement source: main p.5, article p.5 · Results and discussion · Figure S18

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Temperature effect on humidity response	Capacitance increased with temperature; different working temperatures have slight effect on sensing performance	—	—	Text Qualitative	main p.5, article p.5 · Results and discussion · Figure S18