Fig. 1. Schematic of the Hg²⁺ cation exchange mechanism of Hg_xCd_1-xTe QDs（a）crystal structure，and（b）band gap

Fig. 2. （a）Photoluminescence spectra，（b）absorption spectra of Hg_xCd_1-xTe quantum dots with the increase of Hg²⁺ concentration，（c）band gap of Hg_xCd_1-xTe quantum dots with the increase of Hg²⁺ concentration，and（d）time-resolved photoluminescence decay curves of Hg_xCd_1-xTe quantum dots

Fig. 3. （a）TEM image and（d）HRTEM image of 626nm CdTe quantum dots.（b）TEM image and（e）HRTEM image of Hg_0.05 Cd_0.95Te quantum dots.（c）TEM image and（f）HRTEM image of Hg_0.42 Cd_0.58 quantum dots

Fig. 4. （a）Fourier transform infrared spectra of OA，Cd（OA）₂，CdTe，HgCdTe at wavenumber of 1 800-1 000cm^-1.（b）XRD patterns of CdTe quantum dots with fluorescence emission peak at 626 nm，Hg_xCd_1-xTe quantum dots at 723 nm and 815 nm

Fig. 5. （a）The photoluminescence intensity of Hg_0.33Cd_0.67Te QDs at 0-100℃，（b）The relationship between temperature and the photoluminescence intensity of Hg_0.33Cd_0.67Te QDs，（c）Variable photoluminescence of Hg_0.33Cd_0.67Te QDs with the increase of Hg_0.33Cd_0.67Te QDs’ concentration，（d）The relationship between the concentration change of Hg_0.33Cd_0.67Te QDs and photoluminescence intensity