All-inorganic perovskites of CsPbBr 3 nanocrystals (NCs) exhibit strong X-ray absorption and have been demonstrated to be highly efficient scintillators for X-ray detection and imaging. However, the long-term stability of the perovskite remains a major hurdle in practical applications, especially under a commercial dose of X-ray irradiation (0.5−5.5 mGy• s −1 ). Herein, with a solution-protected annealing approach reconstructing the CsPbBr 3 NCs free from undesired defects, the perovskite scintillators provide a long-term (∼3600 s) stable visualization tool for X-ray radiography (1.44 × 10 6 captured images for the exposure time of 2.5 ms per image) under the irradiation dose of 1 mGy•s −1 . This work opens a window for the stability of perovskite scintillators and demonstrates their robust and long-term efficient radioluminescence (RL) for low-cost radiography and X-ray imaging application.
An all-inorganic cesium lead halide perovskite is particularly attractive as an alternative to next-generation display with high quantum yields and color purity for lasers, light-emitting diode (LED) devices, and single-photon sources. Unfortunately, the vulnerable properties induced by moisture limit the hopeful application of CsPbBr 3 , especially for high-performance devices. In this work, a monoclinic CsPbBr 3 derived from hexagonal Cs 4 PbBr 6 with the assistance of water was presented. Moisture-induced decomposition and phase segregation were recorded at the atomic level in detail. Moreover, the obtained monoclinic CsPbBr 3 nanocrystals (NCs) are demonstrated to be decorated with hydroxyl (OH) ligands, which provide a valid approach for the resistance to further moisture attack. The highly stable CsPbBr 3 NCs could preserve the photoluminescence intensity above 97% even after the sample was deposited in water for 30 days. Furthermore, a white LED constructed with the as-prepared green-emitting CsPbBr 3 and a commercial N628 red phosphor demonstrate the monoclinic CsPbBr 3 as a compelling material platform well suited to applications as next-generation light emitters.
Exploring novel electrode composites and their unique interface physics plays a significant role in tuning electrochemical properties for boosting the performance of sodium‐ion batteries (SIBs). Herein, mixed‐dimensional G/NiS2‐MoS2 heterostructures are synthesized in a low‐cost meteorological vulcanization process. The stable graphene supporting layer and nanowire heterostructure guarantee an outstanding structural stability to tolerate certain volume changes during the charge/discharge process. The rational construction of NiS2‐MoS2 heterostructures induces abundant interfaces and unique ion diffusion channels, which render fast electrochemical kinetics and superior reversible capacities for high‐performance SIBs. Interestingly, theoretical studies reveal that the anisotropic diffusion barriers create unidirectional “high‐speed” channels, which can lead to ordered and fast Na+ insertion/extraction in designed heterostructures. G/NiS2‐MoS2 anode exhibits a high capacity of 509.6 mA h g−1 after 500 cycles and a coulombic efficiency >99% at 0.5 A g−1, which also displays excellent cycling performance with the capacity of 383.8 mA h g−1 after the 1000 cycles at 5 A g−1. Furthermore, full cells are constructed exhibiting a high capacity of 70 mA h g−1 at 0.1 A g−1 after 150 cycles and applied to light LEDs. This study provides a feasible strategy of constructing mixed‐dimensional heterostructures for SIBs with excellent performance and a long service lifetime.
An
understanding of growth and degradation pathways is significant
to solve the problem of the structural instability of all-inorganic
perovskite nanocrystals (NCs). However, it is still a great challenge
to directly record such dynamic processes with high spatial resolution
owing to the existence of complex internal factors even using in situ transmission electron microscopy observation. Here,
we employ a glassy matrix to produce CsPbBr3 NCs to ensure
that the growth and degradation processes of CsPbBr3 NCs
are recorded in the vacuum chamber, which could avoid the influence
of the external factors, under electron beam (E-beam) irradiation.
In addition, two stages of degradation pathways induced by the E-beam
are observed sequentially: (1) a layer-by-layer decomposition and
(2) instantaneous vanishing once the radius reaches the critical radius
(∼2.3 nm). Indeed, we demonstrated that defects serve as a
key flash point that could trigger the structural collapse of CsPbBr3 NCs. Our findings provide critical insights into the general
instability issue of all-inorganic perovskite NCs in practical applications.
Owing to their high conductivity and carrier mobility, the outstanding achievements of lead halide perovskites have been demonstrated in humidity sensor applications.
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