Synthesis and luminescence mechanism of multicolor-emitting g-C(3)N(4) nanopowders by low temperature thermal condensation of melamine

Graphite like C(3)N(4 )(g-C(3)N(4)) was synthesized facilely via the low temperature thermal condensation of melamine between 300–650°C. The results showed that the products maintained as melamine when the temperature is below 300°C. With the increase of temperature, the products were transformed into carbon nitride and amorphous g-C(3)N(4) successively. The morphology of products was changed from spherical nanoparticles of melamine into layer carbon nitride and g-C(3)N(4) with the increase of temperature. The photoluminescence spectra showed that the carbon nitride products have continuous tunable photoluminescence properties in the visible region with increasing temperature. With the help of steady state, transient state time-resolved photoluminescence spectra and Raman microstructural characterization, a novel tunable photoluminescence mechanism was founded systematically, which is mainly related to the two dimensional π-conjugated polymeric network and the lone pair of the carbon nitride.