Surface modification of Y₂O₃:Er,Yb upconversion nanoparticles prepared by laser ablation in water

Abstract

Y 2 O 3 :Er,Yb upconversion nanoparticles were prepared by laser ablation in liquid and capped with poly(ethylene glycol) (PEG). A Nd:YAG green laser with nanosecond pulse duration was used. Capping was carried out by a two-step process. The first step is surface modification using a silane coupling agent, (3-aminopropyl)triethoxysilane (APTES), to aminate the surface of nanoparticles. The second step was the conjugation of PEG chains to the surface by amido binding reaction between the surface amino groups and activated esters connected to PEG. The prepared upconversion nanoparticles were highly crystalline polycrystals, the particle size of which was approximately 20 nm. Dopants in phosphor nanoparticles were not removed by laser irradiation. The spectra of PEG-capped nanoparticles were almost the same as those of uncapped nanoparticles. The capped nanoparticles would be useful for biomedical applications.

Laser Synthesis and Processing of Colloids: Fundamentals and Applications

“…Water-insoluble long-afterglow NPs (e.g., Sr 2 MgSi 2 O 7 :Eu 2+ ,Dy 3+ ) synthesized by LAL are another interesting group of luminescent nanophosphors for lighting devices because they allow prolonged emission after switching off the excitation light. , Among all of the doped luminescent particles, upconverting NPs with anti-Stokes upconversion (high-energy photons generation via low-energy photons’ absorption) luminescent emission are particularly attractive for bioimaging, volumetric displays, and photonics applications . Direct synthesis of Y 2 O 3 :Er,Yb upconverting NPs by LAL and their dispersibility control by silane coupling and PEG conjugation have been presented by the Wada group. The LAL-prepared Y 2 O 3 :Er,Yb NPs maintain high crystallinity of the target and have upconversion optical properties comparable to those synthesized by the sol–gel method .…”

Synthesis and Application of Nanohybrids Based on Upconverting Nanoparticles and Polymers

“…This is in favor of keeping the UC efficiency. The generally employed amphiphilic polymers include PEG‐lipid, octylaimne–poly(acrylic acid)–polyethylene glycol (OA–PAA–PEG) copolymer, octylamine and isopropylamine modified PAA, poly((ethylene glycol)‐block‐lactic acid) (PEG‐b‐PLA), poly‐(ethylene glycol)‐block‐poly(carprolactone) (PEG‐b‐PCL), poly(styrene‐block‐allyl alcohol) (PS‐b‐PAA), poly(maleicanhydride‐alt‐1‐octadecene) (PMAO), Jeffamine 2000 grafted poly(styrene‐co‐maleic anhydride), Jeffamine 2070 and PEG grafted PMAO, TWEEN, and gelatin …”