Responsive luminescence materials with prolonged lifetime and multicolor emission have drawn great attention due to their attractive optical property and potential applications. Herein, two responsive carbon dots (CDs) based composites: CD₁@MCM-22P and CD₂@ZSM-12 were achieved by a one-step hydrothermal method. By adjusting the hydrothermal condition, CD₁@MCM-22P owns temperature-dependent afterglow, while CD₂@ZSM-12 is equipped with excitation-dependent room-temperature phosphorescence. The photoluminescence mechanisms of CD₁@MCM-22P and CD₂@ZSM-12 were investigated and proposed, and the composites were applied in multi-mode anti-counterfeiting. This work provides an insight as well as a feasible method for the development of multi-emissive CDs@zeolite composite.

Deep-red and near-infrared emissive carbon dots (CDs) are highly desired for bioimaging, especially in deep tissue imaging, but they are extremely rare and the known ones usually suffer from low-efficient fluorescence in water and aggregation-induced fluorescence quenching in solid state. In this work, CDs with intriguing solvent-dependent and two-photon fluorescence emissions have been prepared by a facile solvothermal method. Detailed characterizations reveal that there is an n→π* interaction between the carboxyl functional groups on CDs and the electron donor groups in solvent, which leads to the increase of energy density of CDs and the decrease of energy level, resulting in the red shift of luminescence with enhanced electron donating ability of solvent. Inspired by this finding, mesoporous silica nanoparticles (MSNs) with suitable pore size and low biological toxicity are modified by amino groups to confine CDs, thus the deep-red fluorescence emission is achieved both in solid state and in water facilitated by the n→π* interaction of host–guest. The as-prepared CDs@EDA-MSN composite exhibits high-efficient fluorescence with 650 nm wavelength, low toxicity, and good biocompatibility, which endow them a promising application in bio-imaging.

In light of the exceptional optical qualities, luminous carbon dots (CDs), particularly those with room-temperature phosphorescence (RTP), have a wide range of applications in a variety of fields. However, modulating afterglow emissions practically and efficiently remains a serious difficulty. Herein, a feasible strategy of calcination combined with in-situ synthesis is proposed to fabricate CDs-based composites with multicolor fluorescence (FL) and phosphorescence. Through pre-selection of small pore RHO zeolite as a matrix, CDs have been successfully embedded due to strong guest–host interaction achieved by in-situ hydrothermal synthesis. By the unique pore architecture and excellent stability of the zeolite matrix, the surface oxidation degree and the carbon core size of confined CDs are engineered by temperature-controlled calcination. The resulting composites exhibit tunable FL (from 416 to 566 nm) and RTP (from 440 to 585 nm) in solid and aqueous solution, in which rarely occurring deep blue RTP is observed with a lifetime as long as 573 ms. Furthermore, the universality of such a calcination-modulated luminescent method has been proved by the AFI zeolite matrix. This study offers up a new way to regulate the luminescence of CDs facilitated by matrix, which considerably promotes the potential applications of CDs-based composites in the future.