The instability of lead halide perovskites (LHPs) has tremendously hindered their practical applications. Although some examples on encapsulating LHPs into a SiO2 shell have been reported, these SiO2-coated LHPs still suffer from limited stability. Herein, MAPbBr3 (MA = CH3NH3 +) nanoparticles encapsulated in double hydrophobic shells of organic functionalized SiO2 and poly­(vinylidene fluoride) (MAPbBr3@SiO2/PVDF) are successfully synthesized by infiltrating the MAPbBr3 precursor solution into hollow siliceous nanospheres and followed by PVDF capping. With the dual protection of SiO2 and PVDF, the MAPbBr3@SiO2/PVDF nanoparticles exhibit drastically improved stability against water and UV-light illumination. A white light-emitting diode with luminous efficiency up to 147.5 lm W–1 and a color gamut encompassing 120% of National Television System Committee in Commission Internationale de L’Eclairage 1931 color space has been demonstrated using the MAPbBr3@SiO2/PVDF nanoparticles as the green light source. This study enlightens new insights into the synthesis of highly stable LHPs-based core–shell–shell architectures toward their practical applications.

Most chemical vapor deposition methods for transition metal dichalcogenides use an extremely small amount of precursor to render large single-crystal flakes, which usually causes low coverage of the materials on the substrate. In this study, a self-capping vapor-liquid-solid reaction is proposed to fabricate large-grain, continuous MoS 2 films. An intermediate liquid phase-Na 2 Mo 2 O 7 is formed through a eutectic reaction of MoO 3 and NaF, followed by being sulfurized into MoS 2 . The as-formed MoS 2 seeds function as a capping layer that reduces the nucleation density and promotes lateral growth. By tuning the driving force of the reaction, large mono/bilayer (1.1 mm/200 μm) flakes or full-coverage films (with a record-high average grain size of 450 μm) can be grown on centimeter-scale substrates. The field-effect transistors fabricated from the full-coverage films show high mobility (33 and 49 cm 2 V −1 s −1 for the mono and bilayer regions) and on/off ratio (1 ~ 5 × 10 8 ) across a 1.5 cm × 1.5 cm region.

Mn doped caesium lead halide perovskite (CsPbCl3‐Mn) nanocrystals are obtained from CsPbBr3 nanocrystals via ion exchange with MnCl2. The doping of Mn and the activity in energy acceptance in different stages of ion exchange are proved using photoluminescence (PL) lifetime measurement and inductively coupled plasma mass spectrometry measurements. During the ion exchange, ultrasonic treatment and cold flow (in a KCl matrix) are used to assist Mn incorporation. The resulting CsPbCl3‐Mn@KCl shows excellent PL properties and stability. Finally, the CsPbCl3‐Mn@KCl tablet is applied to the production of a light emitting diode prototype.

The design of photoluminescence-quenching probes for molecular oxygen (O) is always a large space to explore. Luminescent semiconductor nanocrystals (NCs) have been proposed as emerging oxygen-responsive probes, but the inherent O sensing of phosphorescent semiconductor NCs has not been reported so far. Here, we demonstrate the O sensing capability of Mn-doped CsPbCl nanocrystals (Mn:CsPbCl NCs) and reveal the role of O on the optical de-excitation process of such perovskite nanocrystals (PNCs). By adjusting the amount and distribution of Mn dopants, as well as the host-dopant energy transfer process in PNCs, we highlight that O can reversibly quench the Mn emission due to the temporary disturbance to the ligand field of near-surface Mn dopants in PNCs. In phosphorescence mode, the photoluminescence intensity of the Mn:CsPbCl NCs is quenched by 53% on increasing O concentration from 0 to 100%. The Stern-Volmer plot shows a good linear in the 0-12% O concentration range. High sensing reversibility and rapid signal response are also achieved. In our perception, the mechanism study makes our PNCs candidates for the optical probes of O, and it is enlightening to explore more possibilities of the inherent O sensing based on the semiconductor-doped NCs (not restricted to Mn-doped PNCs) with phosphorescence emission.