Luminescent carbon nanodots from coffee - Luminescent nanodots are useful materials for cell imaging, optoelectronics and solar cells; however, highly toxic chemicals are needed to prepare these materials, raising concerns over their safety. Now, scientists from Taiwan have developed a less toxic way to create luminescent carbon nanodots by using waste coffee grounds. Original reference: P-C Hsu, Z-Y Shih, C-H Lee and H-T Chang, Green Chem., 2012, DOI: 10.1039/c2gc16451e