Tunability of emission color is of great importance in the development of organic light-emitting materials and devices. Fluorescent organic nanoparticles have inspired growing research interests recently because of their variability and flexibility in materials synthesis and nanoparticle preparations as well as high potentials in the application of optoelectronic materials and devices.

As an extension of previous research work on nanoparticles from a series of pyrazoline compounds, 4-(dicyanomethylene)-2-methyl-6-(p-dimethyl-aminostyryl)-4H-pyran (DCM), a red emission materials widely used in EL devices, doped 1, 3, 5-triphenyl-2-pyrazoline (TPP) nanoparticles have been prepared with DCM as the acceptor and TPP the donor. Highly efficient energy transfer dominated by the Förster resonance mechanism as well as tunable emission from blue to red dependent on the DCM doping content was observed in the nanoparticles. The energy transfer and the red-shift of the emission of DCM caused by the aggregation of itself are supposed to be responsible for the tunable emission. The polymer films with doped nanoparticles dispersed in showing tunable emission have been prepared successfully which gave an experimental demonstration of emission tuning in the practical forms. Other than tuning emission by size, the work reported here provides an alternative facile and effective way to control the emission of organic nanoparticles by employing the doping technique and is likely to be interesting to the communities in the areas of optoelectronic materials and devices.

This work has been published in the journal Advanced Materials (2005，17，

2070-2073).