CuInS₂ (CIS) quantum dots (QDs) are known to be ideal fluorophores based on their low toxicity and tunable emission. However, due to low quantum yield (QY) and photostability, the surface is usually passivated by a higher bandgap shell (e.g. ZnS). This always resulted in a blue-shifted emission position which is not usually favourable for biological imaging. To address this problem, we herein report the passivation of green synthesized near infra-red emitting glutathione (GSH) capped CuInS₂ QDs using different concentration of sodium alginate (SA) at different temperatures. The as-synthesized QDs are small (~ 3.2 nm), highly crystalline and emitted in the near infra-red region. The optical results showed a 36% increase in photostability and a 2-fold increase in quantum yield at ratio 1:8 (SA: CIS) which is suitable for prolonged biological imaging applications. Transmission electron microscope and X-ray diffraction (XRD) analyses showed that the materials are highly crystalline without any change in shape and size after passivation with the biopolymer.

由于CuInS ₂（CIS）量子点（QD）的低毒性和可调发射性，因此是理想的荧光团。但是，由于低量子产率（QY）和光稳定性，表面通常被带隙较高的壳（例如ZnS）钝化。这总是导致发射位置发生蓝移，这通常不利于生物成像。为了解决这个问题，我们在此报告了绿色合成的近红外发射谷胱甘肽（GSH）封端的CuInS ₂的钝化在不同温度下使用不同浓度的海藻酸钠（SA）的QD。合成后的量子点很小（〜3.2 nm），高度结晶，并在近红外区域发射。光学结果表明，以1：8（SA：CIS）的比例，光稳定性提高了36％，量子产率提高了2倍，适用于长时间的生物成像应用。透射电子显微镜和X射线衍射（XRD）分析表明，该材料是高度结晶的，在用生物聚合物钝化后，形状和尺寸没有任何变化。