Synthesis and Elementary Exciton Dynamics of CdxZn1-xSe Nanoplatelets

Alloyed semiconductor nanoplatelets (NPLs) exhibit thickness- and composition-dependent luminescence bands with relatively narrow luminescence linewidths, thus garnering significant attention for applications in LED and laser devices. Although understanding Auger recombination is crucial for these applications, the influence of the chemical composition of alloyed NPLs remains unclear. In this study, CdxZn1−xSe NPLs with various chemical compositions were synthesized, and Auger recombination was investigated using femtosecond transient absorption spectroscopy. An increase in Zn content within alloyed NPLs led to a shortening of the time constant of the biexciton Auger recombination. The final density of states, which is a critical factor in Auger recombination, was found to be larger in alloyed NPLs with an increased Zn content than in CdSe NPLs because of their heavier effective masses. These findings provide a deeper understanding of the fundamental physical properties of alloyed NPLs and pave the way for the advancement of applications utilizing these materials.