Organic Phosphorescent Hopper-Shaped Microstructures.

Hopper-shaped microcrystals, an unusual type of crystal with a large specific surface area, are promising for use in catalysis, drug delivery, and gas sensors. In contrast to well-studied inorganic hopper-shaped crystals, organic phosphorescent concave hopper-shaped microstructures are rarely reported. This study reports the synthesis of two types of organic stepped indented hopper-shaped microstructures with efficient room temperature phosphorescence (RTP) using a liquid phase self-assembly strategy. The formation mechanism is attributed to the interfacial instability induced by the concentration gradient and selective etching. Compared with flat microstructures, the stepped indented hopper-like RTP microstructures exhibit high sensitivity to oxygen. This work also demonstrates that packing the photochromic material into the concave hopper "vessel" effectively controls the switch of phosphorescence from energy transfer, expanding the potential applications of phosphorescent materials.

Edible Ultralong Organic Phosphorescent Excipient for Afterglow Visualizing the Quality of Tablets.

Stimuli-responsive ultralong organic phosphorescence (UOP) materials that in response to external factors such as light, heat, and atmosphere have raised a tremendous research interest in fields of optoelectronics, anticounterfeiting labeling, biosensing, and bioimaging. However, for practical applications in life and health fields, some fundamental requirements such as biocompatibility and biodegradability are still challenging for conventional inorganic and aromatic-based stimuli-responsive UOP systems. Herein, an edible excipient, sodium carboxymethyl cellulose (SCC), of which UOP properties exhibit intrinsically multistimuli responses to excited wavelength, pressure, and moisture, is reported. Impressively, as a UOP probe, SCC enables nondestructive detection of hardness with superb contrast (signal-to-background ratio up to 120), while exhibiting a response sensitivity to moisture that is more than 5.0 times higher than that observed in conventional fluorescence. Additionally, its applicability for hardness monitoring and high-moisture warning for tablets containing a moisture-sensitive drug, with the quality of the drug being determinable through the naked-eye visible UOP, is demonstrated. This work not only elucidates the reason for stimulative corresponding properties in SCC but also makes a major step forward in extending the potential applications of stimuli-responsive UOP materials in manufacturing high-quality and safe medicine.

Narrowband room temperature phosphorescence of closed-loop molecules through the multiple resonance effect.

Luminescent materials with narrowband emission show great potential for diverse applications in optoelectronics. Purely organic phosphors with room-temperature phosphorescence (RTP) have made significant success in rationally manipulating quantum efficiency, lifetimes, and colour gamut in the past years, but there is limited attention on the purity of the RTP colours. Herein we report a series of closed-loop molecules with narrowband phosphorescence by multiple resonance effect, which significantly improves the colour purity of RTP. Phosphors show narrowband phosphorescence with full width at half maxima (FWHM) of 30 nm after doping into a rigid benzophenone matrix under ambient conditions, of which the RTP efficiency reaches 51.8%. At 77 K, the FWHM of phosphorescence is only 11 nm. Meanwhile, the colour of narrowband RTP can be tuned from sky blue to green with the modification of methyl groups. Additionally, the potential applications in X-ray imaging and display are demonstrated. This work not only outlines a design principle for developing narrowband RTP materials but also makes a major step forward extending the potential applications of narrowband luminescent materials in optoelectronics.