Lead halide perovskites are emerging as promising candidates for high-efficiency light-emitting diode (LED) applications because of their tunable band gaps and high quantum yield (QY). However, it remains a challenge to obtain stable red emitting materials with high QY. Herein, we report a facile and convenient hot-injection strategy to synthesize Mn-doped two-dimensional (2D) perovskite nanosheets. The emission peak can be tuned from 597 to 658 nm by manipulating the crystal field strength. In particular, a QY as high as 97% for 2D perovskite is achieved. The as-prepared perovskite also possesses excellent stability, whose emission property can be maintained for almost one year. A monochrome LED is further fabricated by employing the as-prepared perovskite as phosphor, which also shows high long-term stability. We believe that these highly efficient and stable perovskites will open up new opportunities in LED applications.

Hybrid composites with great potential for white light LED and temperature sensing obtained through a simple, low cost, and environmental benign way is highly desirable and remains a challengeable task. Herein we present luminescent hybrid composites both in the form of powder and transparent film by simply mixing organic sensitizer, aminoclay (AC), and lanthanide (Ln(3+)) in aqueous solution, the emission color of which can be fine-tuned by changing various parameters such as the molar ratio of Eu(3+) to Tb(3+), excitation wavelength, and the temperature. White lights with satisfied color coordinates have been achieved. The emission intensity ratio of (5)D4 → (7)F5 transition (Tb(3+)) to (5)D0 → (7)F2 transition (Eu(3+)) of the composite containing both Eu(3+) and Tb(3+) can be linearly related to temperature in the range from 78 K to 288 K. These characteristics make the composites suitable for optoelectronic devices such as thermosensors and white light LED.

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A series of robust, color-tunable and self-healing luminescent hydrogels were constructed via self-assembly strategy driven by the electrostatic interaction of positively-charged luminescent micelles consisting of lanthanide complexes and negatively-charged clay nanosheets in aqueous solution.

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