K George Jesna, Ramu Shwetharani, Halali Vishaka V, Balakrishna R Geetha
Centre for Nano and Material Sciences, Jain University, Jakkasandra Post, Bangalore Rural 562112, India.
ACS Appl Mater Interfaces. 2021 Dec 8;13(48):57264-57273. doi: 10.1021/acsami.1c17061. Epub 2021 Nov 23.
Perovskite quantum dots (PQDs) exhibit exceptional fluorescence property and are potential candidates for fluorescent metal-ion sensors. The present work shows the presence of inner filter effect (IFE) in perovskite sensing systems and its significance in enhancing the detection limits. Two different sensing systems (with a different extent of IFE), one with simple long-chain monodentate ligand-capped PQDs and the other with short-chain bidentate ligand capped PQDs, were developed toward sensing Co. The fluorescence quenching mechanism is elucidated and is observed to be a combination of Forster resonance energy transfer (FRET) and IFE. The electrostatic interaction of donor (D) with acceptor (A) and its distance for energy transfer was appropriate and was well within the requirement for a good energy transfer from PQDs (donor) to Co ions (acceptor) facilitating partial FRET. Also, the spectral overlap of absorption of excited and emitted radiation (of PQDs) with that of Co allows a significant amount of IFE. PQDs were successfully modified for lesser spectral overlap with reduced IFE. The reduction in IFE adversely drops the detection levels from 0.733 × 10 to 0.7970 × 10 on modification. This work provides insights into the design and development of high sensing perovskite probes with manipulation of IFE and also shows the importance of IFE to be considered during the study of such sensing systems, which has been neglected so far in perovskite systems.
钙钛矿量子点（PQDs）具有出色的荧光特性，是荧光金属离子传感器的潜在候选材料。目前的工作表明了钙钛矿传感系统中存在内滤光效应（IFE）及其在提高检测限方面的重要性。开发了两种不同的传感系统（具有不同程度的IFE），一种是用简单的长链单齿配体封端的PQDs，另一种是用短链双齿配体封端的PQDs，用于检测钴。阐明了荧光猝灭机制，观察到它是福斯特共振能量转移（FRET）和IFE的组合。供体（D）与受体（A）的静电相互作用及其能量转移距离是合适的，完全符合从PQDs（供体）到钴离子（受体）进行良好能量转移以促进部分FRET的要求。此外，PQDs的激发和发射辐射的吸收光谱与钴的吸收光谱有显著重叠，从而产生大量的IFE。成功地对PQDs进行了修饰，以减少光谱重叠和IFE。修饰后IFE的降低不利地使检测水平从0.733×10降至0.7970×10。这项工作为通过控制IFE设计和开发高灵敏度钙钛矿探针提供了见解，也表明了在研究此类传感系统时考虑IFE的重要性，而这在钙钛矿系统中迄今一直被忽视。
