Unveiling the impurity-modulated photoluminescence from Mn2+-containing metal chalcogenide semiconductors via Fe2+ doping

Abstract

Doping impurities into Mn²⁺-doped semiconductors is an important strategy for tuning their photophysical properties toward potential optoelectronic applications. However, the modulation mechanism of Mn²⁺-related emission affected by specific impurities still remains mysterious due to the lack of a suitable host model with a precise structure. In this work, a Mn²⁺-containing chalcogenide semiconductor nanocluster model was utilized as a host to explore Fe²⁺-impurity-modulated photoluminescence. The special host model guarantees that Fe²⁺ impurities can locate in the core region of the cluster, where Fe²⁺ and Mn²⁺ ions are arranged in a relatively short space distance, and the strong coupling interactions concurrently occur between Mn²⁺ ions and Fe²⁺ impurities as well as Mn²⁺ pairs. Photoluminescence (PL) measurements showed that Mn²⁺-related emission properties including intensity and decay lifetime declined dramatically with the introduction of even lightly doped Fe²⁺ impurities, and the nonradiative nature of the Fe²⁺-impurity energy acceptor center was revealed. The results of photoluminescence excitation (PLE) spectra and PL decay dynamics indicated that, apart from the exciton of the cluster host, excited-state Mn²⁺ ions can directly transfer their energy to Fe²⁺ impurities. Additionally, the variation tendency of temperature-dependent Mn²⁺-related PL decay lifetimes affected by Fe²⁺ impurity was manifested to be different from that of the pristine sample. This work provides a fundamental insight into the Mn²⁺-related PL modulation mechanism affected via impurity incorporation, and would advance new material design with diversified impurity incorporation in this cluster model.