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

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‐2 H ‐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.