Ag₂Se Quantum Dots with Tunable Emission in the Second Near-Infrared Window

Abstract

Quantum dots (QDs) with fluorescence in the second near-infrared window (NIR-II, 1000-1400 nm) are ideal fluorophores for in vivo imaging of deep tissue with high signal-to-noise ratios. Ag₂Se (bulk band gap 0.15 eV) is a promising candidate for preparing NIR-II QDs. By using 1-octanethiol as ligand to effectively balance the nucleation and growth, tuning the fluorescence of Ag₂Se QDs was successfully realized in the NIR-II window ranged from 1080 to 1330 nm. The prepared Ag₂Se QDs can be conveniently transferred to the aqueous phase by ligand exchange, showing great potential for multicolor NIR-II fluorescence imaging in vivo.

Growth of photoluminescent Ag2Se nanowires from a simple precursor solution

“…The PLQY was calculated to be 4.4 ± 1.1% against ICG in DMSO (PLQY = 13%), comparable to the PLQY values of Ag 2 Se QDs. 24,25 This was evidenced by the PL spectra of the Ag 2 Se nanowires and Ag 2 Se QDs synthesized by the method reported previously 26 at the same concentration (Fig. S4, ESI †).…”

Synthesis and Thermoelectric Properties of Noble Metal Ternary Chalcogenide Systems of Ag–Au–Se in the Forms of Alloyed Nanoparticles and Colloidal Nanoheterostructures

“…Tunable emission in the near-infrared (NIR) spectral range is of potential value for biosensing and in vivo imaging, whereas solids of such materials can be utilized as photodetectors. [39][40][41][42] Their efficient charge transport, superionic character and high magnetoresistance have motivated the study of their use as solid electrolytes for electrochemical applications as well as magnetic sensors. 43,44 Binary silver chalcogenides have also been tested as thermoelectric materials, showing values of the thermoelectric figure of merit (ZT) close to unity in some cases.…”

Pressure tuning the lattice and optical response of silver sulfide

“…By varying the thickness [16][17][18][19][20] , its activation gap can be effectively tuned. 16 By changing the particle size, its optical band-gap could also be engineered.…”

“…16 By changing the particle size, its optical band-gap could also be engineered. [17][18][19] Compared with the above methods, pressure is a powerful tool in modifying the way atoms arrange and thus to tune materials electronic structure and physical properties. In this work, we aim at solving following tasks: 1) explore possible structural transition at higher pressure, 2) clarify the structural connections among the different phases, 3) and determine how pressure tunes the optical response which relates to the band-gap's and optical conductivity's evolution.…”