Fig. 1: Synthesis and optical characterizations of large InAs/InP/ZnSe/ZnS core/multishell QDs.
From: Efficient and stable near-infrared InAs quantum dot light-emitting diodes
a Scheme of the protocol for synthesizing InAs/InP/ZnSe/ZnS quantum dots (QDs). The InAs core and InP shell are synthesized at 270 °C by reacting indium oleate (InOA3) with tris(trimethylsilyl)arsine ((TMS)3As) and tris(trimethylsilyl) phosphine ((TMS)3P), respectively. The ZnSe shell grows with zinc oleate (ZnOA2) and trioctylphosphine selenide (TOPSe) at 340 °C, while the ZnS shell is formed with zinc octanethiolate (Zn(OTT)2) at 270 °C. ZnF2 is added during ZnSe shell growth to promote isotropic morphology. Absorption (dash line) and photoluminescence (PL) spectra (solid line) of InAs/InP/ZnSe/ZnS QDs with PL peaks at 900 nm (b) and 1050 nm (c). Evolution of absorption spectra (d), PL spectra (e), PL quantum yield (PLQY, light coral) and full width at half maximum (FWHM, sky blue) (f) of the QDs shown in (b) during the overcoating reaction. The dashed line in (e) is inserted as a guide to highlight the shifts in the PL peaks. The error bars of PLQYs and FWHMs in (f) represent the standard deviation of multiple syntheses results with respect to the mean values. g Ensemble PL decays of the final QDs sample.
