Manifested luminescence and magnetic responses of stoichiometry dependent Cd1 − xMnxSe quantum dots

We report on stoichiometry dependent manifested physical properties of thioglycolic acid (TGA) coated Cd1 − xMnxSe QDs. While possessing a wurtzite phase, with increasing x, the QDs exhibited a notable blue-shifting of the onset of absorption. Attributed to VCd–VSe di-vacancies, the QDs describe an intense deep-defect related emission response at smaller values of x (=0 to 0.3). Due to the facilitation of magnetic Mn2+ ion migration from the core to the QD surfaces, 4T1–6A1 transition based Mn2+ orange emission get suppressed at a higher x (=0.6 to 1). While the FT-IR spectra of the alloyed QDs display characteristic Mn–OH stretching mode at ∼644 cm−1, the peak located at ∼703 cm−1 is assigned to Cd-Se bending. Furthermore, the QDs with a low x (=0.3), exhibit paramagnetic characteristics owing to the presence of uncorrelated, isolated Mn2+ spins. The collective luminescence and magnetic features would find immense scope in bio-labeling and imaging applications, apart from solid state luminescent components.