The top-view
and cross-sectional micrographs of the NiOx surface and
fabricated devices were investigated with an ultra-high-resolution
ZEISS Crossbeam scanning electron microscope. The surface morphology
and roughness of the NiOx thin film and NPLs were studied
using a Bruker Innova atomic force microscope. The absorption and
PL spectra of CdSe QDs were recorded with a Princeton Instruments
Acton 2150 spectrophotometer equipped with a Xe lamp as the light
source. The UPS measurements for the NiOx films and NPLs
were performed on a Thermo VG-Scientific/Sigma Probe spectrometer.
A He I (hν = 21.22 eV) discharge lamp was used
as the excitation source. The XPS measurements were conducted on a
Thermo K-Alpha X-ray photoelectron spectrometer for elemental composition
analysis of NiOx. The XRD patterns and crystallinity of
NiOx were measured using a Rigaku D/MAX2500 X-ray diffractometer.
The current density–voltage characteristics of hole- and electron-only
devices were measured using an Agilent 4155C semiconductor parameter
analyzer. The performance and electroluminescence spectra of QLEDs
were recorded using an Agilent 4155C semiconductor parameter analyzer
and an Ocean Optics USB2000+ spectrometer.
and cross-sectional micrographs of the NiOx surface and
fabricated devices were investigated with an ultra-high-resolution
ZEISS Crossbeam scanning electron microscope. The surface morphology
and roughness of the NiOx thin film and NPLs were studied
using a Bruker Innova atomic force microscope. The absorption and
PL spectra of CdSe QDs were recorded with a Princeton Instruments
Acton 2150 spectrophotometer equipped with a Xe lamp as the light
source. The UPS measurements for the NiOx films and NPLs
were performed on a Thermo VG-Scientific/Sigma Probe spectrometer.
A He I (hν = 21.22 eV) discharge lamp was used
as the excitation source. The XPS measurements were conducted on a
Thermo K-Alpha X-ray photoelectron spectrometer for elemental composition
analysis of NiOx. The XRD patterns and crystallinity of
NiOx were measured using a Rigaku D/MAX2500 X-ray diffractometer.
The current density–voltage characteristics of hole- and electron-only
devices were measured using an Agilent 4155C semiconductor parameter
analyzer. The performance and electroluminescence spectra of QLEDs
were recorded using an Agilent 4155C semiconductor parameter analyzer
and an Ocean Optics USB2000+ spectrometer.