Phosphorous doped carbon dots (P-CDs), prepared by a one-step hydrothermal method, show the phenomenon of aggregation induced red shift emission (AIRSE).

Combination of excellent optical properties and ferroelectricity of hybrid materials leads to high-performance optoelectronic devices. Here we present a new organic-inorganic hybrid compound (diisopropylammonium)MnBr (DIPAMnBr) which shows high temperature ferroelectricity accompanied by highly efficient green-light emission. DIPAMnBr also exhibits sensitive and selective optical response to alcohol vapors.

Halide perovskites (HPs) are promising materials for preparing nonvolatile memory and artificial synapse devices. However, the instability and toxicity of lead HPs seriously restrict their further application. Herein, a lead-free...

It is well known that the electrochemical performance of spinel LiMn2O4 can be improved by Al doping. Herein, combining X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, and spherical aberration-corrected scanning transmission electron microscopy (Cs-STEM) with in situ electron-beam (E-beam) irradiation techniques, the influence of Al doping on the structural evolution and stability improvement of the LiMn2O4 cathode material is revealed. It is revealed that an appropriate concentration of Al3+ ions could dope into the spinel structure to form a more stable LiAl x Mn2–x O4 phase framework, which can effectively stabilize the surface and bulk structure by inhibiting the dissolution of Mn ions during cycling. The optimized LiAl0.05Mn1.95O4 sample exhibits a superior capacity retention ratio of 80% after 1000 cycles at 10 C (1 C = 148 mA h g–1) in the voltage range of 3.0–4.5 V, which possesses an initial discharge capacity of 90.3 mA h g–1. Compared with the undoped LiMn2O4 sample, the Al-doped sample also shows superior rate performance, especially the capacity recovery performance.

Organometallic halide perovskites have been demonstrated to be very promising for nonlinear optics and practical frequency upconversion devices in integrated photonics. In this work, high quality organometallic halide CH 3 NH 3 PbBr 3 perovskite thin films were synthesized through a solution-based one-step spin-coating method. With femtosecond optical pumping at 1300 nm, frequency-upconverted random lasing (RL) from the bromide perovskite films were achieved via three-photon (3P) absorption processes. The RL spectra show no spikes due to the large scattering mean-free path in the perovskite crystals, meaning the incoherent RL emission with incoherent feedback. In comparison with the one-photon pumped situation, it is found that both the two-photon and 3P excitations are more effective in reducing the RL threshold, despite the low conversion efficiency of their nonlinear multiphoton schemes. Moreover, the time-and spectralresolved lasing characteristics of the laser pulses were systematically explored by time-resolved photoluminescence based on an optical Kerr-gate method. The measured ultrashort 3.1 ps output pulse is the shortest one that has been observed so far in bromide perovskite random lasers, without any postprocessing. In addition, wavelength dependence of the pulse width and delay time of the RL pulses were clearly demonstrated, and could be unravelled by intraband carrier relaxation dynamics, which is an important physical mechanism in ultrafast lasers. Our results demonstrate that organometallic halide perovskites are excellent gain medium for high-performance frequency upconversion random lasers and have great potential for use in gain-switched semiconductor lasers with ultrashort output pulses and tunable emission wavelengths across the entire visible spectrum.

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Waterborne polymers are advantageous in terms of cost, convenience, sustainability, and environmental friendliness. As lead halide perovskite (LHP) nanocrystals suffer from fast degradation in the presence of water, it is challenging to encapsulate LHP nanocrystals in waterborne polymers. In this work, luminescent MAPbBr 3 @PbBr(OH) nanocrystals were synthesized via the aqueous grinding process in the presence of 2-methyl-imidazole (2-MIM) and oleylamime (OAm). 2-MIM triggers the formation of the PbBr(OH) matrix, and OAm acts as a size-control ligand to control the size of MAPbBr 3 @PbBrOH particles in the nanoscale range. Highly stable waterborne luminescent inks were successfully prepared by blending MAPbBr 3 @PbBr(OH) nanocrystals with waterborne polymers, including poly(vinylpyrrolidone), poly(vinyl acetate), and acrylate resins. Owning to the dual protection of the polymer matrix and PbBr(OH) to LHP quantum dots (QDs), the luminescent films exhibit excellent stability to the environment under thermal and light irradiation. The ink can be used as a phosphor to fabricate down-converting green and white light-emitting diodes (LEDs). Waterborne anticounterfeiting inks suitable for screen printing were prepared via formula tuning for the anticounterfeit purpose. The anticounterfeiting luminescent patterns can be screen printed on paper, cloth, and poly(ethylene terephthalate) (PET), with encryption and decryption of information being accurately and conveniently realized by switching UV irradiation.

The formation of CH3NH3PbBr3 nanocrystals and silicone resin composites greatly improves the stability of CH3NH3PbBr3 nanocrystals against water, heat and UV exposure.