The stability of perovskite solar cells, especially at high temperature (85 °C) conditions, is one of the most critical aspects to advance practical application. All-inorganic perovskites, by substituting the volatile organic compounds with cesium, have exhibited a promising thermal resistance and energy conversion potentials. However, the thermal stability of the all-inorganic perovskite solar cells is strongly related to the phase transition of the perovskite as well as the thermal resistance of each charge transport and collection layer. Herein, we incorporated Eu­(Ac)3 into the perovskite precursor to fabricate photoactive γ-CsPbI2Br. The Eu3+ ions can associate with the negatively charged halide plumbates in the solution and accumulate at the grain boundaries in the as-achieved thin films, effectively reducing the nonradiative recombination centers and stabilizing the γ-CsPbI2Br with moderate grain size. A champion efficiency above 12% in an inverted device architecture can be achieved. In the presence of Eu3+ ions, the phase transition of the γ-CsPbI2Br to nonperovskite is significantly mitigated and can be reversibly restored via thermal repairing. Moreover, we thermally treat the electron transport [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) layer prior to the device completion to induce nanomorphology reorientation and replace the reactive Ag electrode by inert Cu to prevent electrode corrosion by diffusive halide ions from the perovskite. As a result, the thermal (at 85 °C, time to 80% of the initial efficiency or t 80 ≈ 200 h) and moisture (relative humidity or RH = 40%, t 80 > 500 h) stability of the all-inorganic CsPbI2Br solar cells can be remarkably enhanced.

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Inorganic lead halide perovskites (ILHPs), an emerging class of semiconductors, hold great potential for a broad spectrum of applications, ranging from solar cells and light-emitting diodes (LEDs) to scintillators and lasers, due to ILHPs’ exceptional optical/electronic properties. The properties of ILHPs are closely related to their micro-/nanostructures, and thus controlling the micro-/nanostructures of ILHPs is highly desired to promote further development. Self-assembly, a common but powerful method, has recently been explored for the synthesis and control of the micro-/nanostructures of ILHPs. In this Review, we first summarize recent advances in the self-assembly of ILHPs into micro-/nanostructures and pay attention to main factors that can influence the self-assembly process. We then illustrate representative applications of the self-assembled micro-/nanostructures of ILHPs, including photodetectors, LEDs, lasers, and X-ray imaging. And last, we offer our perspectives on the self-assembled micro-/nanostructures of ILHPs, particularly their applications.

some intriguing and complex nanostructures, like branched heteronanocrystals, can be obtained in the presence of anion additives. [11] Despite the advance of the anion additive-based modulation, this strategy is applied to limited types of inorganic nanomaterials, such as metal, semiconductor, metal oxide, and metal halide nanomaterials. [9] It is therefore of great interest to explore the influences of anion additives on characteristics of other inorganic nanomaterials.Lanthanide-doped upconversion nanoparticles (UCNPs), possessing the ability to convert low-energy photons to highenergy ones, arise as a type of versatile inorganic luminescent nanomaterials. [13][14][15][16] The unique luminescent features of UCNPs, such as high photostability, large anti-Stokes shift, and tunable luminescent