Single-source precursor synthesis of quinary AgInGaZnS QDs with tunable photoluminescence emission

Mn-Doped Quinary Ag–In–Ga–Zn–S Quantum Dots for Dual-Modal Imaging

“…Mn-doped Ag−In−Ga−Zn−S (Mn:AIGZS) QDs were synthesized in a two-stage process. 37 First, a Ag, In, Ga, and Zn dithiocarbamate complex (Ag x In y Ga 2−x−y Zn 2 (S 2 CN-(C 2 H 5 ) 2 ) 4 ) used as a precursor was prepared using a Ag/In/ Ga/Zn ratio of 0.25:0.875:0.875:2 to obtain AIGZS QDs that did not emit light in the same spectral window as Mn-doped QDs. The loading in the MnSt 2 dopant was calculated relative to the total amount of metal cations and varied from 1 to 10%.…”

“…Figure a shows the UV–vis absorption and the PL emission spectra of AIGZS and Mn-doped AIGZS QDs with loadings in Mn 2+ of 1, 2.5, 5, and 10%. The absence of distinctive absorption is typical for multinary QDs and originates from heterogeneous composition distributions among the dots and thus due to the distribution of vibrational states in AIGZS QDs. − The absorption spectral profiles of AIGZS and Mn:AIGZS QDs are almost similar, indicating that both the diameter and the composition of the dots are not significantly modified by the doping. The band gap values of the dots are determined from the Tauc plots of (α h ν) 2 vs h ν, where α is the absorption coefficient and h ν is the photon energy, and are found to decrease from 2.94 for AIGZS QDs to 2.58 eV for Mn(10):AIGZS QDs (Figure b).…”

“…The single precursor used for the synthesis of AIGZS QDs was prepared according to our previous report. 37 Briefly, AgNO 3 (0.25 mmol), In(NO 3 ) 3 (0.875 mmol), Ga(NO 3 ) 3 (0.875 mmol), and Zn(DDTC) 2 (2 mmol) (a Ag/In/Ga/Zn molar ratio of 0.25:0.875:0.875:2) were mixed using OAm as a solvent. First, the precursor (100 mg) and the appropriate amount of MnSt 2 were dispersed in OAm (6 mL) and the mixture was stirred under an Ar flow until getting a clear solution.…”

“…Binary CdS, 26 PbS, 27 ZnS, 28,29 and ZnSe, 30−32 ternary In−Zn−S, 33 We recently reported the synthesis of highly luminescent quinary Ag−In−Ga−Zn−S (AIGZS) QDs via thermal decomposition in oleylamine (OAm) of a single Ag x In y Ga 2−x−y Zn 2 (S 2 CN(C 2 H 5 ) 2 ) 4 dithiocarbamate precursor. 37 In this study, we used the heavy-metal-free AIGZS QDs as host nanocrystals to incorporate Mn 2+ dopants, and the dual functional (PL/MRI) properties of the doped QDs were investigated. Our results showed that Mn-doped AIGZS (Mn:AIGZS) QDs exhibited the Mn 2+ -related 4 T 1 → 6 A 1 PL with a PL quantum yield (PL QY) of up to 41.3% and a high PL lifetime of up to 887.9 μs.…”

“…We recently reported the synthesis of highly luminescent quinary Ag–In–Ga–Zn–S (AIGZS) QDs via thermal decomposition in oleylamine (OAm) of a single Ag x In y Ga 2– x – y Zn 2 (S 2 CN­(C 2 H 5 ) 2 ) 4 dithiocarbamate precursor . In this study, we used the heavy-metal-free AIGZS QDs as host nanocrystals to incorporate Mn 2+ dopants, and the dual functional (PL/MRI) properties of the doped QDs were investigated.…”