Surface modification and fabrication of white‐light‐emitting Tm³⁺/CdS quantum dots co‐doped glass fibers

Abstract

Due to the widely tunable band gap and broadband excitation, CdS quantum dots (QDs) show great promise for yellow‐light luminescence center in white‐light‐emitting devices. The light intensity of the CdS QD‐doped glass was enhanced by doping the Tm3+ ions due to the higher absorption rate. The influence of Tm3+ ions on the surface structure of CdS QDs was enormous according to the first‐principles calculations. Doping Tm3+ ions change the surface state of CdS QDs, which will fix the QDs emission peaks and enhance the luminescence of CdS QDs at a lower heat‐treatment temperature. White‐light emission was obtained by tuning the relative concentration between Tm3+/CdS QDs. However, there is a fundamental challenge to fabricate QD‐doped glass fibers by rod‐in‐tube method since uncontrollable QDs crystallization is hard to avoid. Herein, a white‐light‐emitting borosilicate glass fiber was fabricated by the “melt‐in‐tube” method using a special designed Tm3+/CdS QDs co‐doped borosilicate glass with low‐melting temperature as fiber core. After heat treatment, ideal white‐light emission was observed from the fiber under excitation at single wavelength (359 nm). This finding indicates that Tm3+/CdS QDs co‐doped glass fiber with white‐light‐emitting devices has potential application as gain medium of white‐light‐emitting sources and fiber lasers.

PbSe Quantum Dot Doped Mode-Locked Fiber Laser

“…In addition, QDs have large cross-sections, which implies high optical gain. Further, QDs can be easily embedded into a fiber [ 16 , 17 ]. Theoretically, QDs are an excellent gain medium for use in mode-locked fiber lasers.…”

Light-Generating CdSe/CdS Colloidal Quantum Dot-Doped Plastic Optical Fibers

“…One could argue that historically the first quantum-confining nanocrystals were made by melting both glass and semiconductor precursors at high temperature, − nucleating quantum dots throughout the glass structure, and hence naturally yielding preforms for the first category of nanocomposite optical fibers. − This glass melt-quenching method does not allow for elaborate control of the nanocrystal surface passivation, , thus defects degrade the PL emission, creating further challenges to control the density of nanocrystals and their size distribution. − A second category of debatably nanocomposite fibers thus recently emerged: doping optical fibers with cQDs using a number of postprocessing techniques, such as filling hollow core fibers with a liquid containing cQDs − and coating the core of microstructured optical fibers − or fiber tapers and ends. − These techniques seem a priori advantageous in their chemical simplicity and flexibility, benefiting from the separate synthesis of cQDs under well controlled conditions enabling passivation with heterostructures of multiple semiconductor shells , and even with further surface ligand exchange afterward. ,, However, the lack of stability and robustness coupled with high optical losses in the cQD host solvents limits the practicality of liquid core fibers, with the added drawback of air exposure when the solvent evaporates, causing surface chemical reactions that increase photobleaching and photoactivation.…”