Cesium–lead based inorganic perovskite quantum-dots as interfacial layer for highly stable perovskite solar cells with exceeding 21% efficiency
Date
2019Source Title
Nano Energy
Print ISSN
2211-2855
Publisher
Elsevier
Volume
60
Pages
557 - 566
Language
English
Type
ArticleItem Usage Stats
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Abstract
Despite the excellent photovoltaic performances of perovskite solar cells (PSCs), the instability of PSCs under
severe environment (e.g. humidity, light-induced, etc.) limits further commercialization of such devices.
Therefore, in recent years, research on the long-term stability improvement of PSCs has been actively carried out
in perovskite field. To address these issues, we demonstrated the incorporation of ultra-thin interfacial layer of
inorganic CsPbBr1.85I1.15 perovskite quantum-dots (PQDs) that can effectively passivate defects at or near to the
perovskite/hole transport material (HTM) interface, significantly suppressing interfacial recombination. This
passivation layer increased the open circuit voltage (Voc) of triple-cation perovskite cells by as much as 50 mV,
with champion cells achieving Voc ∼ 1.14 V. As a result, we obtained hysteresis-free cells with the efficiency
beyond 21%. More importantly, devices based on such architecture are capable of resisting humidity and lightinduced. Remarkably, the device employing CsPbBr1.85I1.15 demonstrated a superb shelf-stability aganist to
humidity under ambient conditions (R.H.≥40%), retaining nearly 91% of initial efficiency after 30 days, while
the efficiency of control device rapidly dropped to 45% from its initial value under the same conditions. Besides
benefiting from the high moisture resistivity as well as supressed ion migration, PSCs based on PQDs showed
better operational stability (retaining 94% of their initial performance) than that of the PQDs-free one under
continuous light irradiation over 400 h. In addition, a faster PL decay time of 4.66 ns was attained for perovskite/PQDs structure (5.77 ns for only PQDs structure) due to the favorable energy transfer at the interface,
indicating a Förster resonance energy transfer (FRET) mechanism. This work indicates that inorganic PQDs are
important materials as interlayer in PSCs to supremely enhance the device stability and efficiency.
Keywords
CsPbBrxI3-x inorganic perovskite quantum-dotsInterfacial layer
Stability
Perovskite solar cells