Spectroscopy

Hard X-ray photoemission spectroscopy (HAXPES)

CVD Cu-BHT nanofilm series · Thin Film

Ga K alpha HAXPES lab system with hnu = 9252.4 eV; survey and core level scans; samples stored/transported under nitrogen/inert conditions.

Atmosphere: inert handling before measurement
Geometry: CVD nanofilms of varied thickness
Context: pristine Cu-BHT films and solution reference
Measurement source: SI p.S6 and p.S13-S14 · Hard X-ray photoemission spectroscopy · Figure 2f; Figures S10-S12; Table S1

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Cu 2p1/2 binding energy	953.1 eV	—	—	Text Exact Reported	main p.3 / article p.C · Results and Discussion · Figure S11
Cu 2p3/2 main peak assigned to Cu(I)	main peak at 932.6 eV; no significant satellite peaks; exclusive Cu(I)	—	—	Text Exact Reported	main p.3 / article p.C · Results and Discussion · Figure 2f
Cu 2p3/2 binding energy	932.3 eV	—	—	Text Exact Reported	main p.3 / article p.C · Results and Discussion · Figure S11
Cu0 subpeak fraction in sputtered CuO precursor by Al K alpha HAXPES	ca. 10% of total copper	0.1 fraction	—	Caption Approximate	SI p.S14 · Results and Discussion · Figure S12
Cu0 subpeak fraction in sputtered CuO precursor by Ga K alpha HAXPES	ca. 30% of total copper	0.3 fraction	—	Caption Approximate	SI p.S14 · Results and Discussion · Figure S12
S 1s peak maximum	maximum at 2470 eV with broad shoulder at higher BE	—	—	Text Rounded Reported	main p.3 / article p.C · Results and Discussion · Figure 2f
S/Cu ratio, CVD Cu-BHT 20 nm	2.7	—	—	SI Table Exact Reported	SI p.S14 · Results and Discussion · Table S1
S/Cu ratio, CVD Cu-BHT 40 nm	2.6	—	—	SI Table Exact Reported	SI p.S14 · Results and Discussion · Table S1
S/Cu ratio, CVD Cu-BHT 80 nm	2.7	—	—	SI Table Exact Reported	SI p.S14 · Results and Discussion · Table S1
S/Cu ratio, Cu-BHT powder reference	12.4	—	—	SI Table Exact Reported	SI p.S14 · Results and Discussion · Table S1

CVD Cu-BHT nanofilm series · Thin Film

Transmission mode on Lambda 950 UV-Vis spectrophotometer.

Geometry: glass/Cu-BHT films
Context: pristine Cu-BHT films on glass
Measurement source: SI p.S6 and p.S18 · Ultraviolet-Visible-Near infrared spectroscopy · Figure S20

Property	Reported value	Normalised value	Uncertainty	Origin and quality	Source
Average transmittance drop for 20 nm Cu-BHT on glass	7.7% drop in 400-2500 nm region	0.077 fractional drop	—	Caption Exact Reported	SI p.S18 · Results and Discussion · Figure S20
Average transmittance drop for 85 nm Cu-BHT on glass	47.6% drop in 400-2500 nm region	0.476 fractional drop	—	Caption Exact Reported	SI p.S18 · Results and Discussion · Figure S20