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As a promising optoelectronic material, all-inorganic perovskite nanocrystals (NCs) have attracted much attention, but there are few studies on zero-dimensional Cs4PbBr6 perovskite NCs. Herein, the in situ growth of the CsPbBr3/Cs4PbBr6 NCs inside amorphous glass has been achieved by adjusting the ratios of Cs2CO3 and PbBr2. The effect of different proportions with raw materials on the phase, microstructure, and photoluminescence (PL) characteristics was discussed in detail. Moreover, CsPbBr3/Cs4PbBr6 NCs glass with high photoluminescence quantum yield (PLQY) of ∼58.9% was obtained by optimizing the heat treatment condition. In particular, CsPbBr3/Cs4PbBr6 NCs glass realizes low-threshold amplified spontaneous emission (ASE) at room temperature. Meanwhile, as a green light source, CsPbBr3/Cs4PbBr6 NCs glass makes white light-emitting diode (WLED) presents a wide color gamut. Importantly, CsPbBr3/Cs4PbBr6 NCs glass displays excellent water/thermal stability. All these results prove that CsPbBr3/Cs4PbBr6 NCs glass has broad application prospects in the field of lasers and backlight displays. [ABSTRACT FROM AUTHOR]

Carbon nanotubes (∼200 nm diameter) are grown by chemical vapor deposition using catalytic iron particles. Mössbauer spectroscopy enables differentiation among relatively large Fe3C, α-Fe, and nanosized superparamagnetic fcc γ-Fe particles. The antiferromagnetic configuration of γ-Fe nanoparticles yields a significant fraction of uncompensated spins, producing a weak ferromagnetism that allows estimation of size (2–3 nm) via magnetization in zero field versus variable field cooling. This property of γ-Fe nanoparticles has not been previously employed. We propose that the surfaces of 200 nm iron carbide particles are covered with nanosized γ-Fe and graphitized carbon that participate in the catalytic growth of nanotubes. [ABSTRACT FROM AUTHOR]