Hydroxypropyl chitosan-Cs₃Bi₂Cl₉ perovskite quantum dots (HPCS-PQDs) were synthesized by a simple ligand-assisted reprecipitation method via green hydroxypropyl chitosan as the ligand and used as the specific signal of a fluorescence probe to achieve the highly sensitive detection of hexavalent chromium (Cr(VI)) and compared with chitosan-Cs₃Bi₂Cl₉ QDs (CS-PQDs). HPCS-PQDs with multiple active hydroxyl passivations were found to enhance the photoluminescence quantum yield (PLQY) by 90%. After being placed in aqueous solution and irradiated with ultraviolet light for 96 h the fluorescence intensity of HPCS-PQDs remained above 60%. The blue emission of HPCS-PQDs has a good selectivity and short response time (30 s) for Cr(VI). A good linear relationship is established between the fluorescence quenching rate of the HPCS-PQDs and concentration of Cr(VI) from 0.8 to 400 µM, with a limit of detection (LOD) of 0.27 µM. The fluorescence quenching mechanism is the static quenching and internal filtration effect caused by HPCS-PQDs forming a non-fluorescent ground-state complex with Cr(VI). The sensor can not only be used to detect Cr(VI) in water samples with high accuracy but can also be prepared as a test paper for the detection for Cr(VI).

Graphical Abstract

中文翻译：

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羟丙基壳聚糖钝化铋基钙钛矿量子点对六价铬的视觉快速荧光传感

以绿色羟丙基壳聚糖为配体，采用简单的配体辅助再沉淀法合成羟丙基壳聚糖-Cs 3 Bi 2 Cl 9 钙钛矿量子点（HPCS-PQDs），并作为荧光探针的特异性_信号，_实现高灵敏_检测六价铬 (Cr(VI)) 的含量并与壳聚糖-Cs ₃ Bi ₂ Cl ₉ QD (CS-PQD) 进行比较。研究发现，具有多个活性羟基钝化的 HPCS-PQD 可以将光致发光量子产率 (PLQY) 提高 90%。将HPCS-PQDs置于水溶液中并用紫外光照射96 h后，HPCS-PQDs的荧光强度仍保持在60%以上。 HPCS-PQDs 的蓝光发射对 Cr(VI) 具有良好的选择性和较短的响应时间（30 s）。 HPCS-PQDs 的荧光猝灭率与 Cr(VI) 浓度在 0.8 至 400 µM 范围内建立了良好的线性关系，检测限 (LOD) 为 0.27 µM。荧光猝灭机制是HPCS-PQDs与Cr(VI)形成非荧光基态络合物引起的静态猝灭和内部过滤效应。该传感器不仅可以高精度检测水样中的Cr(VI)，而且可以制备成检测Cr(VI)的试纸。

图形概要