Disulfide Crosslinking‐Induced Aggregation: Towards Solid‐State Fluorescent Carbon Dots with Vastly Different Emission Colors^†

Abstract

Comprehensive Summary Solid‐state fluorescent multi‐color carbon dots (SFM‐CDs), prepared using the same precursor(s) without the need for dispersion in a solid matrix, are highly demanded for a wide range of applications. Herein, we report a microwave‐assisted strategy for the preparation of SFM‐CDs with blue, yellow and red emissions within 5 min from the same precursors. The as‐prepared B‐CDs, Y‐CDs, and R‐CDs possessed bright fluorescence at 425 nm, 550 nm, and 640 nm, and photoluminescence quantum yields (PLQYs) of 54.68%, 17.93%, and 2.88%, respectively. The structure of SFM‐CDs consisted of 5‐oxo‐3,5‐dihydro‐2H‐thiazolo [3,2‐a] pyridine‐7‐carboxylic acid (TPCA) immobilized on the surface of a carbon core, with the size of the carbon core and degree of disulfide crosslinking between CDs both increasing on going from the B‐CDs to the R‐CDs, as verified by mechanochromic experiments. The excellent solid‐state fluorescence performance of the SFM‐CDs allowed their utilization as the fluorescent converter layer in multi‐color LEDs and white LEDs with a high color rendering index.

Fluorescent Silk Obtained by Feeding Silkworms with Fluorescent Materials†

“…Compared with organic fluorescent molecules, CDs have more simple synthesis steps, stronger photostability and chemical stability. [ 75‐76 ] Compared with metal quantum dots/metal oxide nanoparticles, CDs are easier to degrade, more environmentally friendly, and have better biocompatibility which is based on the biomass sources. [ 77‐78 ] These characteristics endow CDs with wide application potential in environmental monitoring and biological techniques.…”

Supramolecular Surface Engineering of Carbon Dots Enables Matrix‐Free Room Temperature Phosphorescence†

“…[ 7‐11 ] CDs have been widely used in sensing, in vitro / in vivo imaging, cancer therapy, catalysts and optoelectronic devices. [ 12‐19 ] Despite the well documented fluorescent properties, CDs with RTP have also been reported by several groups. [ 20 ] Lin and co‐workers reported the production of effective RTP by aggregation‐induced of CDs in trimellitic acid.…”

Deep‐Red to Near‐Infrared Carbon Dots in Biosensing and Bio‐medical Applications

“…For this reason, a number of long‐wavelength emitting CDs have been developed consecutively. [ 15‐16 ] To begin with, CDs synthesized by the solvothermal method emitted red fluorescence (emission peak, em = 603 nm) depending on the surface state produced by surface oxidation, but the QY was low (20.6%) (Figure 1a). [ 17 ] Subsequently, red‐emitting CDs were prepared by hydrothermal method with phenylene diamine and urea, which could further induce a red‐shift in emission wavelength, but the QY was still comparatively low (24%) (Figure 1b).…”