Nanoconfined Synthesis of Lead Sulfide Quantum Dots Embedded in Mesoporous Aluminosilicate Glass with Adjustable Near-Infrared Broadband Luminescence

Abstract

Functionalizing glass with optically active quantum dots has shown great potential in near-infrared bioimaging and optical communication. However, the size distribution of quantum dots is hard to control by traditional glass quenching method due to extremely high processing temperature (∼1300 °C), resulting in unexpected transmission loss and luminescent quenching of quantum dots embedded in a glass composite. Herein, we developed a nanoconfined synthesis of lead sulfide (PbS) quantum dots in a mesoporous aluminosilicate glass matrix at a relatively low temperature of 600 °C with adjustable near-infrared broadband luminescence. The sol−gel-synthesized glass composite precursor with high surface areas over 480 m 2 /g and a nanopore mean diameter of about 3.2 nm can enable the homogeneous dispersal of PbS quantum dots in the mesoporous glass matrix as well as restrict the overgrowth of quantum dots to prevent aggregation. The PbS−AS glass composites exhibited dual-band near-infrared luminescence, showcasing morphological and nonlinear saturable absorption properties. The 0.8PbS−AS glass served as an effective saturable absorber for a passively mode-locked Er-doped fiber laser, achieving a pulse repetition rate of ∼0.09 kHz/mW and a pulse width of ∼0.04 μs/kHz. The PbS−SA is confirmed to be suitable for a Q-switched mode-locking laser, showing high potential for mode-locked laser generation with further SA optimization.