Abstract：
In conventional ratiometric photoelectrochemical (PEC) sensors, the detection and reference signals are output sequentially from two independent photosensitive materials. In such a \"two-to-two\" ratiometric mode, unavoidable difference during dual-interface modification exists, resulting in questionable ratiometric signals and detection results. To address this issue, we propose a novel \"one-to-two\" ratiometric PEC sensor on a single electrode interface through pH-modulated band alignment engineering. The double ratiometric signals are generated by the synergistic action of a pH-responsive CuTCPP/WS2 photoelectric substrate material and the i-motif sensing tool. Specifically, a ternary heterostructure to generate a photoanodic detection signal is formed under alkaline conditions between CuTCPP/WS2 and signal label CdS QDs binding to the i-motif. While under acidic conditions, a photocurrent polarity conversion and signaling labels detachment, induced by the band realignment of CuTCPP/WS2 and the i-motif conformational switching, produce a reliable internal reference photocathodic signal. The feasibility of this two-wing signal generation strategy is validated by detecting mycotoxin ochratoxin A, which achieves accurate and reliable ratio detection results. Overall, this work provides guidance for the design of a PEC ratiometric determination system and exhibits great potential to be applied in practical analysis research.
摘要：
在传统的比例光电化学(PEC)传感器中，检测和参考信号从两个独立的光敏材料顺序输出。在这种“二对二”比率模式下，在双界面修改过程中存在不可避免的差异，导致可疑的比率信号和检测结果。为了解决这个问题，我们提出了一种新型的“一对二”比例PEC传感器在单电极界面上通过pH调制带对准工程。通过pH响应性CuTCPP/WS2光电衬底材料和i-基序感测工具的协同作用产生双比率信号。具体来说,在碱性条件下,在CuTCPP/WS2和与i-基序结合的信号标记CdSQD之间形成用于产生光阳极检测信号的三元异质结构。在酸性条件下，光电流极性转换和信号标签分离，由CuTCPP/WS2的能带重排和i基序构象转换引起，产生可靠的内部参考光阴信号。通过检测霉菌毒素曲霉毒素A，验证了这种双翼信号产生策略的可行性。实现了准确可靠的比值检测结果。总的来说,这项工作为PEC比率测定系统的设计提供了指导，并具有在实际分析研究中应用的巨大潜力。
