Glutathione-Capped Au Nanoclusters Embedded in NaCl Crystals for White Light-Emitting Devices

In this paper, an ultrafacile and efficient approach was proposed to simultaneously enhance the luminescence emission and stability of glutathione-capped gold nanoclusters (GSH-Au NCs) using sodium chloride (NaCl) as a cost-effective and eco-friendly confining matrix. The approach was performed by simply mixing the Au NCs with a saturated NaCl aqueous solution, followed by a natural crystallization procedure. The prepared GSH-Au NCs/NaCl crystal presented bright orange emission with an absolute luminescence quantum yield of 30%, which increased 30-fold compared with GSH-Au NCs (1%). Moreover, the GSH-Au NCs/NaCl crystal exhibited much higher thermal emission stability and photostability than GSH-Au NCs and can be preserved under ambient conditions for 14 months without an obvious loss in luminescence emission. Mechanism studies revealed that the improved luminescent properties were mainly attributed to the confinement and protection effects of NaCl. Such a strategy can also be extended for confining blue-emitting GSH-capped copper nanoclusters (GSH-Cu NCs) into NaCl crystals. On these bases, GSH-Au NCs/NaCl and GSH-Cu NCs/NaCl were used as color-converting phosphors for the fabrication of a prototype of white light-emitting devices, potentially applicable for solid-state lighting.