We synthesized luminescent CsPbBr3 nanocrystals with a high quantum yield and realized patterning and color-purity light-emitting diode applications.

We demonstrated a green avenue to continuous mass production of stably fluorescent perovskite nanocrystal composite materials via a microfluidic spinning technique, potentially useful for application in WLEDs and displays.

Hybrid organic-inorganic and all-inorganic metal halide perovskite nanocrystals (PNCs) have aroused extensive attention from both academic and industrial researchers, considering their excellent performance in optoelectronic applications. Herein, we develop a facile and time-saving strategy to synthesize NHCH═NHPbBr (NHCH═NH, FA) PNCs at room temperature. Benefiting from this facile method, high-quality FAPbBr PNCs with photoluminescence quantum yield up to 76% and narrow full width at half-maxima of 20 nm can be produced on a large scale. Moreover, anion-exchange reactions run by using FAPbBr as a template, producing various PNCs with different anion constituents. By manipulating the ratios of two different anions, a series PNCs with various bright photoluminescence ranging from 452 to 646 nm could be done. On account of superior and adjustable photoluminescence over the visible spectral region, FAPbBr PNCs can be applied as a promising color-converting material in liquid-crystal display (LCD) backlight, white light-emitting diode (WLED), and inkjet printing pattern. As a proof of concept, FAPbBr PNCs with green emission were integrated in WLED and LCD backlight, accomplishing a color rendering index of 87.5 and a wide color gamut of 116%, respectively.

Carbon dots (CDs) have attracted increasing interest in recent years owing to their desirable properties. Despite the availability of diverse elaborate CDs, the function and application of CDs are far to be fully exploited. Here, biomass-derived carbon dots dispersed in a polymer matrix are found to behave as ink-free patterned substrates, which are demonstrated to be useful for nondestructive collection and recognition of latent fingerprints (LFPs), as well as printing. The coating of CD/poly(vinyl alcohol) solution on a LFP yields a flexible transparent film; a stable fluorescent fingerprint with clear ridge details enabling personal identification is formed on this film. Encouragingly, this method can be applied to nondestructively lift and recognize long-timely exposed LFPs from various surfaces. The mechanism for LFP collection and visualization is proposed, which should be ascribed to the interfacial segregation of CDs in the polymer matrix during the film forming process. This mechanism is further validated by and utilized for application of CD/polymer composites in relief printing, intaglio printing, and micro-trace transferring.