Near-Infrared Emitting AgInS₂/ZnS Nanocrystals

Abstract

Near-infrared emitting AgInS2/ZnS nanocrystals were synthesized by carefully controlling the growth conditions in a Ag/In/Zn/S solution with less zinc relative to the other precursors. The role of having a smaller amount of zinc (8 atom %) was systematically investigated in an effort to understand the mechanism of the largely red-shifted emission. The AgInS2/ZnS nanocrystals can be transferred to aqueous solutions while retaining the emission intensity. The near-infrared emission and solubility in aqueous solutions make AgInS2/ZnS nanocrystals excellent candidates for bioimaging and photocatalytic applications.

Synthetic Developments of Nontoxic Quantum Dots

“…The dots were very thermally stable and were used as an optical filter to increase the warmth of a blue–white LED. The synthesis of core/shell AgInS 2 /ZnS has also been extensively explored, and interestingly the same issue of shell formation, vs. alloying has been observed. Regardless of the nature of the photoluminescence enhancement, these NIR emitters have been extensively used for in vitro and in vivo bioimaging applications.…”

Room‐Temperature Ionic‐Liquid‐Assisted Microwave Preparation of Tunable Photoluminescent Copper‐Indium‐Zinc‐Sulfide Quantum Dots

“…It was believed that the two PL decay times t 1 (fast)a nd t 2 (slow) are associated with the surface defects and the donoracceptorp air (DAP) recombination of holes and electrons trapped in the intrinsic defects, respectively. [10,13] As can be seen in Figure 5a nd Table 1, the fast decay component (B 1 )i ncreasesf rom 24.72 to 38.03 %a st he molar ratio n [Bmim] /n C increasest o5 ;t his phenomenon was attributed to the decreasedsize of the QDs, which results in the increase of surface defects. Moreover, B 1 gradually decreases to 20.56 %w ith the increaseo ft he molar ratio n [Bmim] /n C from 5t o1 0.…”

“…Furthermore, the slow decay time of the samples ranges from 335.16 to 415.04 ns, indicating that the emission mechanism of CIZS QDs is associated with defect-related radiation recombination. [10] In addition to [Bmim]BF 4 ,o ther RTILs with different anions were utilized to assess the effects of the RTIL on the reaction and illustrate the universality of the route. The analogous [Bmim]Cla nd [Bmim]Br were used.…”

“…The emission mechanism of I-III-VIQ Ds is supposed to be the defect-relatede mission, which is mainly induced by deep trap states (e.g.,v acancies and interstitial atoms). [10] The PL property of CIZS QDs was furthera djusted by tuning the amount of defects. On the basis of the above results, [Bmim]BF 4 was chosen as the optimal RTIL, and the molar ratio n RTIL /n C wasf ixed at 10.…”

“…[9] The emission mechanismo fI -III-VIQ Ds is supposed to be defect-related emission, which is mainly inducedb yd eep trap states (e.g.,v acancies and interstitial atoms). [10] Many researchers have reported the synthesis of CIZS QDs with high quantum yield (QY) in organicm edia. [1,3,9] However,t heir hydrophobic property limits their application in the field of biology.O n the other hand, the transition from hydrophobic QDs into hydrophilic QDs through al igand-exchange process caused a dramatic decrease of the QY from 41 to 17 %.…”