The perovskite-based optoelectronic
applications always suffer
from stability issues, due to the intrinsic chemical instability of
the perovskite materials. Besides, poly(3,4-ethylenedioxythiophene):polystyrenesulfonate
(PEDOT:PSS) is always utilized as an anode buffer layer in thin-film
perovskite light-emitting diodes (PeLEDs), which may lead to stability
issues due to the hygroscopic and acidic nature of PEDOT:PSS. In this
paper, inorganic metal oxide NiO
x
is employed
as a hole injection layer (HIL) and hole transport layer (HTL) to
substitute detrimental PEDOT:PSS in all-inorganic PeLEDs. Then fully
covered CsPbBr3 polycrystalline films are fabricated by
using a one-step spin-coating method based on nonstoichiometric and
polymer-assisted perovskite precursor solutions. The optimized films
not only have compact morphology but also have excellent photoluminescence
quantum yield (PLQY). Encouragingly, by introducing a metal oxide
NiO
x
, the CsPbBr3 PeLEDs show
a maximum luminance of 23 828 cd m–2 and
maximum current efficiency (CE) of 9.54 cd A–1,
which lead to a 1.6-fold and 3.3-fold increase compared to the PeLEDs
with a PEDOT:PSS HIL. Besides, the inorganic PeLEDs show high color
purity with a full-width at half-maximum (fwhm) of only 16 nm. The
combination of inorganic NiO
x
with inorganic
perovskite also shows improved operation stability of devices, which
paves the way for highly efficient all-inorganic PeLEDs.
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