Abstract
Here, we proposed a novel synthetic technique to get highly luminescent QDs. The thallium ions were used for the first time to modulate the optical behavior of the PbS QDs. High quality Pb1-xTlxS QDs were prepared via 1,3,5-tris-N-phenylbenzimidazole-2-yl-benzene assisted hydrothermal technique. The X-ray measurements demonstrated the preserving of cubic phase of PbS nanocrystals. The TEM measurements disclosed the increase of the particle-size of the Pb1-xTlxS QD from 4.1 nm to 9 nm. The optical performance of these nanocrystals was modulated through the include of Tl in crystal lattice structure of PbS, where the bandgap decreased from 1.4 eV to 1.24 eV. The Tl-dopant promoted the emission intensity and established color tunable quantum dots. The quantum yield of the Pb1-xTlxS QDs increased from 10 to 81 % due to the Tl-dopant. These marvel characteristics may force the developed Pb1-xTlxS QDs to be used for the production of laser in IR-region, optical sensors and IR-decoders potential applications.