Porous ZnS/ZnO microspheres prepared through the spontaneous organization of nanoparticles and their application as supports of holding CdTe quantum dots

This manuscript describes a self-organization method for the large-scale production of porous ZnS/ZnO composite microspheres and their application as supports of CdTe quantum dots. Through the reaction of Zn 2+ and urea and thioacetamide at 85 °C for 10 min, nanoparticles of cubic ZnS and amorphous ZnO were formed and they present a strong tendency to organize into regular microspheres. The formation of nanopores within the microspheres is related to Ostwald ripening: some small nanoparticles within the microspheres were merged by the larger ones, and as a result, numerous nanopores were generated. Furthermore, when a solvothermal ripening is applied for the porous microspheres, the components within them can be transformed into hexagonal ZnS and ZnO. CdTe quantum dots were introduced into the nanopores to achieve luminescent microspheres through in situ nucleation and growth. And it is expected that, besides semiconducting quantum dots, other functional units, such as magnetic and catalytically activated nanoparticles, can also be introduced into them.