Temperature dependence of properties of Mn-doped nanocrystals with different binding symmetry

Highlights: • Mn²⁺ ions were at the interface of the core/shell nanocrystals with different binding symmetry. • Two competing factors affected the excited state lifetimes of all nanocrystals in this work. • Inflexion temperatures of the excited state lifetimes were influenced by the binding symmetry. • Different wave function overlap may affect the mechanism of the two competing factors. We report the temperature dependence of photoluminescent properties of Mn-doped nanocrystals (NCs) with different binding symmetry. The photoluminescence peaks of Mn²⁺ ions shift to shorter wavelength with increasing temperatures, resulting from the reduction of crystal field. Further evidence for temperature-dependent crystal field variety is demonstrated by electronic paramagnetic resonance (EPR) spectra. Additionally, the inflexion temperature of the excited state lifetimes increases from 170 K (Sample I) to 220 K (Sample IV), which is speculated to be resulted from the easily affected wave function overlap due to thermal lattice expansion in more symmetrical binding Mn-doped NCs.