Mn-Doped Nanoparticles Shine In Multiple Colors

Colorful nanoparticles find their way into numerous applications, including solar cells, electronic displays, lighting, and cellular imaging. Cadmium-based particles, which rank among the ones most commonly studied and applied, could be used even more widely if they were tailored through doping to improve their emission characteristics and long-term stability and reduce their toxicity. For those reasons, researchers have turned to manganese. But they believed Mn-doped nanoparticles to be of limited use because the particles fluoresce only in shades of orange. Not so, says Dipankar D. Sarma of the Indian Institute of Science in Bangalore and coworkers. By applying a single-particle photoluminescence technique to analyze hundreds of particles individually, as opposed to evaluating large ensembles collectively, as is commonly done, the team showed that Mn-doped Zn-S-Cd particles emit a spectrum of light from deep green to deep red (Phys. Rev. Lett. 2013, DOI: 10.1103/physrevlett.110.267401). The team also showed that the spectral width of the emitted light is far narrower than commonly assumed, a property that may further enhance Mn-doped nanoparticles’ applicability.