The synthesis and optical properties of GaSe/InSe core/shell nanoparticles

The synthesis of epitaxially grown GaSe/InSe core/shell nanoparticles is reported. InSe shells of 0.25 nm in thickness are grown on GaSe cores of 6 nm in diameter. The shell growth is accompanied by a red shift of the absorption spectrum and a decrease of the room temperature emission intensity. The absorption onset on red side just remains unchanged but that on blue side shifts from 27,840 to 25,266 cm−1, which means that an electron transition occurs between the GaSe core and the InSe shell. Time resolved emission experiments are also performed on the GaSe and the GaSe/InSe core/shell nanoparticles. Emission decay takes place on the 80 ps, 400 ps, and 2.4 ns time scales, while anisotropy decay follows two stages of 400 ps and 2.4 ns. Relaxation kinetics shows that the deep hole traps are effectively suppressed in the GaSe/InSe core/shell nanoparticles. The electron transition between the GaSe core and InSe shell results in a degree of charge separation that makes this core/shell nanoparticle attractive for use in photoelectric conversion devices.