Electrical Transport — Modification of metal-organic interface using F4-TCNQ for enhanced hole injection properties in optoelectronic devices

4 measurement groups · 20 results

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

J-V measurement and SCLC comparison

Space-charge-limited current analysis

alpha-NPD hole-only devices with F4-TCNQ interfaces · Thin Film

F4-TCNQ thickness varied from 0, 1, 5 and 7 nm; observed current density compared with calculated SCLC J value.

Atmosphere: vacuum conditions
Geometry: ITO/F4-TCNQ(x nm)/alpha-NPD(250 nm)/F4-TCNQ(x nm)/Au
Context: model hole-only devices with unmodified and modified interfaces
Measurement source: p005 / article p.2543 · Results and discussion · Figure 3c

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
ITO Fermi level to alpha-NPD HOMO offset	0.6 eV	—	—	Text Rounded Reported	p005 / article p.2543 · Results and discussion · Figure 3c
alpha-NPD HOMO level	5.5 eV	—	—	Text Rounded Reported	p003 / article p.2541 · Experimental
F4-TCNQ thickness required for ohmic contact to alpha-NPDMarked as a best value within this paper	7 nm	—	about in conclusions	Text Rounded Reported	p005 / article p.2543 · Results and discussion · Figure 3c

J-V measurement and injection-efficiency comparison with Child-law SCLC current

Space-charge-limited current analysis

m-MTDATA hole-only devices with F4-TCNQ interfaces · Thin Film

J-V measured with Keithley 2400 in a vacuum cryostat; injection efficiency eta = Jobs/JSCLC calculated using dielectric constant 3 and TOF mobility literature values.

Temperature: room temperature
Atmosphere: vacuum conditions
Geometry: ITO/F4-TCNQ(x nm)/m-MTDATA(250 nm)/F4-TCNQ(x nm)/Au
Context: model hole-only devices with unmodified and 1 nm F4-TCNQ-modified interfaces
Measurement source: p005 / article p.2543 · Results and discussion · Figure 3a

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
m-MTDATA injection efficiency with bare electrodes at 3 V	0.08	—	—	Text Exact Reported	p005 / article p.2543 · Results and discussion · Figure 3a
m-MTDATA HOMO level used in experimental design	5.0 eV	—	—	Text Rounded Reported	p003 / article p.2541 · Experimental
m-MTDATA injection efficiency after 1 nm F4-TCNQ interface layerMarked as a best value within this paper	near to unity for all applied voltages	—	near to	Text Approximate	p005 / article p.2543 · Results and discussion · Figure 3a
F4-TCNQ thickness required for ohmic contact to m-MTDATAMarked as a best value within this paper	1 nm	—	—	Text Rounded Reported	p006 / article p.2544 · Conclusions

J-V measurement and SCLC comparison

Space-charge-limited current analysis

spiro-TAD hole-only devices with F4-TCNQ interfaces · Thin Film

F4-TCNQ thickness varied from 0 to 7 nm; observed current density compared with calculated SCLC J value.

Atmosphere: vacuum conditions
Geometry: ITO/F4-TCNQ(x nm)/spiro-TAD(250 nm)/F4-TCNQ(x nm)/Au
Context: model hole-only devices with unmodified and modified interfaces
Measurement source: p005 / article p.2543 · Results and discussion · Figure 3b

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
ITO Fermi level to spiro-TAD HOMO offset	about 0.5 eV	—	about	Text Approximate	p005 / article p.2543 · Results and discussion · Figure 3b
spiro-TAD HOMO level	5.4 eV	—	—	Text Rounded Reported	p003 / article p.2541 · Experimental
F4-TCNQ thickness required for ohmic contact to spiro-TADMarked as a best value within this paper	7 nm	—	—	Text Rounded Reported	p005 / article p.2543 · Results and discussion · Figure 3b

Kelvin probe method / scanning Kelvin probe microscopy incorporated with AFM

Atomic force microscopy

F4-TCNQ-coated Al, In, Ag, ITO and Au substrate series · Thin Film

Surface potential measured in ambient conditions; grounded metal films and gold probe head; work function estimated by adding surface-potential difference to probe work function.

Atmosphere: ambient conditions
Geometry: conducting substrate with F4-TCNQ thin film
Context: model F4-TCNQ/substrate interfaces, including x = 0 control
Measurement source: p003 / article p.2541 · Experimental · Figure 1

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Ag substrate work function near 7 nm F4-TCNQ	approximately 5.3 eV at 7 nm from Figure 1a	—	visual estimate from plotted axis	Figure Axis Approximate	p003 / article p.2541 · Results and discussion · Figure 1a
Al substrate work function with 7 nm F4-TCNQ	4.3 eV	—	—	Text Rounded Reported	p003 / article p.2541 · Results and discussion · Figure 1a
In substrate work function near 7 nm F4-TCNQ	approximately 4.7 eV at 7 nm from Figure 1a	—	visual estimate from plotted axis	Figure Axis Approximate	p003 / article p.2541 · Results and discussion · Figure 1a
F4-TCNQ-modified ITO and Au work function at 7 nm reported in Introduction	5.35 eV for 7 nm adsorbed layer	—	—	Text Rounded Reported	p002 / article p.2540 · Introduction
Oxygen-plasma-treated ITO work function	4.8 eV	—	—	Text Rounded Reported	p003 / article p.2541 · Experimental
ITO and Au substrate work function with 7 nm F4-TCNQMarked as a best value within this paper	5.37 eV	—	—	Text Rounded Reported	p003 / article p.2541 · Results and discussion · Figure 1a
Approximate saturation work function of modified substratesMarked as a best value within this paper	saturate at about 5.37 eV	—	about	Text Approximate	p003 / article p.2541 · Results and discussion · Figure 1b
Bare conducting-substrate work-function range	3.7-5.1 eV	—	—	Text Range	p002 / article p.2540 · Introduction
Maximum work-function increase after F4-TCNQ modificationMarked as a best value within this paper	about 0.6 eV in nearly all cases	—	about	Text Approximate	p003 / article p.2541 · Results and discussion · Figure 1a
F4-TCNQ thickness for work-function saturationMarked as a best value within this paper	about 7 nm	—	about	Text Approximate	p003 / article p.2541 · Results and discussion · Figure 1a