Patterning Perovskite Nanocrystal layers
A solution of CsPbBr3 PeQDs was spin-coated on glass substrates at 1000rpm for 30s to form the PeQD films.
The films were covered with a patterned mask and irradiated with 254nm UV light for 3min crosslinking.
After irradiation, the PeQD-patterned films were rinsed with benzene.
Figure. 1 (a) TEM image of synthesized nanocrystals. (b) XRD patterns of PeQDs with different ligands with reference patterns of CsPbBr3 structure. (c) FT-IR spectra of AzL1-Th PeQD and AzL2-Th PeQD films.
(d) Schematic diagram for photopatterning process. (e) Fluorescence microscopy images of pristine AzL1-Th-PNC films before and after benzene washing and (f-g) photopatterned AzL1-Th-PNC films.
Photo-Crosslinked Perovskite LEDs
ITO substrate was washed with acetone and isopropanol.
After drying in an oven, the ITO substrates were treated with an O2 plasma for 10 min.
PEDOT:PSS (AI 4083) was spin-coated onto the ITO at 4500 rpm for 40 s and annealed at 140 °C for 10 min.
A Poly-TPD solution (10 mg/mL) in chlorobenzene was spin-coated at 4000 rpm for 40 s, and annealed at 120 °C for 5 min. CsPbBr3 NCs (15 mg/mL) were spin-coated onto the poly-TPD layer at 2000 rpm for 30 s, followed by photo-crosslinking
Finally, TPBi (70 nm), LiF (2.5 nm) and Al (100 nm) were sequentially deposited by the thermal evaporation.
Figure. 2 Photographs showing changes of emission after benzene washing in the PeLEDs based on AzL1-Th-PNC films (a) before crosslink, (b) after crosslink, and (c) after partial crosslink.
Characterization
Transmission electron microscopy images were recorded on a Tecnai G2 F30 S-Twin (FEI, USA).
X-ray diffraction spectra were recorded on a D/max-2500V/PC (Rigaku, Japan).
Fourier-Transform Infrared spectra was recorded on Nicolet iS50 (Thermo, America) using ATR mode.
The Fluorescence microscopy images were recorded DMi8 (LEICA, Germany).