Colloidal l‐cysteine (Cys)‐capped ZnS:Mn nanocrystals were synthesized and exposed to various pH conditions to modify their surface for further applications as photo‐chemical sensors. The observed zeta‐potential values indicated that the ZnS:Mn–Cys nanocrystals formed positive charged nanocrystal surface at pH 3 condition. Therefore, they were considered to be applied as an anion sensor. As a result, the fluorescence of the ZnS:Mn–Cys‐pH 3 nanocrystals was exclusively quenched by the addition of nitrite (NO₂⁻) ions. In addition, the ZnS:Mn–Cys nanocrystals, which were exposed to pH 7 and pH 13, formed negatively charged surfaces, which were presumed to be applied as cation photosensors. Consequently, the fluorescence of the ZnS:Mn–Cys‐pH 7 nanocrystals were amplified by the addition of Zn²⁺ ions, whereas the most added metal ions caused quenching of the emission lights of the ZnS:Mn–Cys‐pH 7 nanocrystals. Moreover, the fluorescence of the ZnS:Mn–Cys‐pH 13 nanocrystals was quenched only when Cu²⁺ ions were added.

中文翻译：

---

半胱氨酸封端的ZnS：Mn纳米晶体在水溶液中的可变传感离子选择性

胶体升半胱氨酸（CYS）加帽的ZnS：锰纳米晶体的合成和暴露于各种pH条件以改变其表面，用于进一步的应用作为光化学传感器。观察到的ζ电势值表明，ZnS：Mn–Cys纳米晶体在pH 3条件下形成带正电的纳米晶体表面。因此，认为它们被用作阴离子传感器。其结果是，所述硫化锌的荧光：锰的Cys-pH为3个纳米晶体是专门通过添加亚硝酸盐（NO的淬灭₂ ^-）离子。此外，暴露于pH 7和pH 13的ZnS：Mn–Cys纳米晶体形成带负电的表面，据推测可将其用作阳离子光电传感器。因此，通过添加Zn ²⁺离子可以放大ZnS：Mn-Cys-pH 7纳米晶体的荧光，而添加最多的金属离子会导致ZnS：Mn-Cys-pH 7纳米晶体的发射光猝灭。此外，仅当添加Cu ²⁺离子时，ZnS：Mn–Cys-pH 13纳米晶体的荧光才被淬灭。