Recent studies have shown that charge transport interlayers with low gas permeability can increase the operational lifetime of perovskite solar cells serving as a barrier for migration of volatile decomposition products from the photoactive layer. Herein we present a hybrid hole transport layer (HTL) comprised of p-type polytriarylamine (PTAA) polymer and vanadium(V) oxide (VO x ). Devices with PTAA/VO x top HTL reach up to 20% efficiency and demonstrate negligible degradation after 4500 h of light soaking, whereas reference cells using PTAA/MoO x as HTL lose ∼50% of their initial efficiency under the same aging conditions. It was shown that the main origin of the enhanced device stability lies in the higher tolerance of VO x toward MAPbI 3 compared to the MoO x interlayer, which tends to facilitate perovskite decomposition. Our results demonstrate that the application of PTAA/VO x hybrid HTL enables long-term operational stability of perovskite solar cells, thus bringing them closer to commercial applications.
Regardless of the impressive photovoltaic performances demonstrated for lead halide perovskite solar cells, their practical implementation is severely impeded by the low device stability. Complex lead halides are sensitive to both light and heat, which are unavoidable under realistic solar cell operational conditions. Suppressing these intrinsic degradation pathways requires a thorough understanding of their mechanistic aspects. Herein, we explored the temperature effects in the light-induced decomposition of MAPbI 3 and PbI 2 thin films under anoxic conditions. The analysis of the aging kinetics revealed that MAPbI 3 photolysis and PbI 2 photolysis have quite high effective activation energies of ∼85 and ∼106 kJ mol −1 , respectively, so decreasing the temperature from 55 to 30 °C can extend the perovskite lifetime by factors of >10−100. These findings suggest that controlling the temperature of the perovskite solar panels might allow the long operational lifetimes (>20 years) required for the practical implementation of this promising technology.
All-inorganic lead halide perovskites,
for example, CsPbI3, are becoming more attractive for applications
as light absorbers
in perovskite solar cells because of higher thermal and photochemical
stability as compared to their hybrid analogues. However, a specific
drawback of the CsPbI3 absorber consists of the rapid phase
transition from black to yellow nonphotoactive phase at low temperatures
(e.g., <100 °C), which is accelerated under exposure to light.
Herein, an experimental screening of an unprecedently large series
(>30) of metal cations in a wide range of concentration has allowed
us to establish a set of Pb2+ substitutes, facilitating
the crystallization of the photoactive black CsPbI3 phase
at low temperatures. Importantly, the appropriate Pb2+ substitution
with Ca2+, Sr2+, Ce3+, Nd3+, Gd3+, Tb3+, Dy2+, Er3+, Yb2+, Lu3+, and Pt2+ cations has
led to a spectacular enhancement of the film stability under realistic
solar cell operation conditions (∼1 sun equivalent light exposure,
50 °C). Optoelectronic, structural, and morphological effects
of partial Pb2+ substitution were investigated, providing
a deeper insight into the processes underlying the stabilization of
the CsPbI3 films. Several CsPb1–x
M
x
I∼3 systems
were evaluated as absorber materials in perovskite solar cells, demonstrating
encouraging light power conversion efficiency of 11.4% in preliminary
experiments. The obtained results feature the potential of designing
efficient and stable all-inorganic perovskite solar cells using novel
absorber materials rationally designed via compositional engineering.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.