An LTCC monolithic microreactor for the synthesis of carbon dots with photoluminescence imaging of the reaction progress

This work describes the development of a fully integrated Low Temperature Co-fired Ceramic (LTCC) microreactor for the synthesis of carbon dots (CDots). The microreactor integrates fluidics, a heating resistor and an optical window for fluorescence imaging of the reaction progress in a monolithic, all ceramic device, ensuring homogeneous surface chemistry and physical properties. A pool of different CDots was synthesized at high temperature and pressure using a hydrothermal method, demonstrating the robustness of the microreactor. The synthesis was monitored by following the photoluminescence of the produced CDots, and the reaction conditions were optimized according to their Quantum Yield (QY) and the flow pattern inside the microchannel. The obtained CDots exhibited blue photoluminescence upon irradiation with UV light with QYs of up to 0.77. The CDots were screened as metal nanoprobes and bioimaging contrast agents.