The specific structure and diverse properties of hybrid organic–inorganic perovskite materials make them suitable for use in photovoltaic and sensing fields. In this study, environmentally stable organic–inorganic hybrid perovskite luminescent materials using Pb–MOF as a particular lead source were prepared using a mechanochemical method. Based on the fluorescence intensity of the MAPbBr3/MOF composite, the mechanized chemical preparation conditions of Pb–MOF were optimized using response surface methodology. Then, the morphological characteristics of the MAPbBr3/MOF composite at different stages were analyzed using electron microscopy to explore its transformation and growth process. Furthermore, the composite form of MAPbBr3with Pb–MOF was studied using XRD and XPS, and the approximate content of MAPbBr3in the composite material was calculated. Benefiting from the increase in reaction sites generated from the crush of Pb–MOF during mechanical grinding, more MAPbBr3was generated with a particle size of approximately 5.2 nm, although the morphology of the composite was significantly different from the initial Pb–MOF. Optimal performance of MAPbBr3/MOF was obtained from Pb–MOF prepared under solvent-free conditions, with a milling time of 30 min, milling frequency of 30 Hz and ball–material of 35:1. It was also confirmed that the mechanochemical method had a good universality in preparing organic–inorganic hybrid perovskite/MOF composites.Keywords:Pb–MOF;organic–inorganic hybrid perovskite/MOF composites;mechanochemical method;optical properties
Yangwen Hou,Man Dong,Jingting He,Jing Sun,Chunyi Sun,Xiao Li,Xinlong Wang,Zhongmin Su
All-inorganic perovskite (CsPbBr3) nanocrystals (NCs) are exceptional candidates for photocatalysis due to their optimal band structure, high molar extinction coefficient, and long charge-carrier diffusion lengths. However, their inevitable instability and low charge transfer efficiency have prevented their widespread applications. A strategy that can improve both stability and charge separation efficiency is desperately required. Herein, by introducing an in situ structural transformation strategy, hydrophobic hierarchically porous CsPbBr3@Pb-MOF is obtained which exhibits high durability in water for more than 7 weeks and appealing thermal stability and resistance to anion intrusion. Meanwhile, abundant oxygen vacancies are detected which efficiently suppress the photogenerated charge recombination. As a result, impressive CO2 photoreduction activity is achieved with CsPbBr3@Pb-MOF as a catalyst. Through a gas–solid reaction (without sacrificial agents and photosensitizers), this CsPbBr3@Pb-MOF-2 composite exhibits a CO yield of 107 μmol g−1 h−1 with 99.2% selectivity under visible-light (λ > 420 nm) irradiation, surpassing most reported CsPbX3-based photocatalysts under similar conditions.
Feng Hong,Qiqin Wang,Wenhai Wang,Xixue Chen,Yuting Cao,Youren Dong,Ning Gan,Dazhen Wu,Futao Hu
How to eliminate the background signal of the electrochemical aptasensor and improve its signal amplification efficiency is one of the key factors to build a highly sensitive and selective sensor. Herein, we developed a multi-signal amplified, zero background electrochemical aptasensor for rapid detection of tumor markers, with carcinoembryonic antigen (CEA) as a model analyte . A type of dendritic DNA scaffold labeled with a lead-based metal organic framework (HCR-Pb-MOF) was prepared by hybrid chain reaction as signal tags. After one-step replacement of the signal tags into the supernatant by the target, the inner Pb 2+ ions in the replaced tags were detected by square-wave voltammetry (SWV) for qualification. The assay has some distinct advantages. Firstly, one HCR-Pb-MOF can load many Pb-MOFs, with each Pb-MOF containing large amounts of Pb 2+ ; thus, multi-amplified signals from Pb 2+ can be obtained after one-step replacement of the target. Secondly, Pb-MOF can also completely avoid the leakage of Pb 2+ , which is usually observed in the MOF probes electrostatically adsorbing metal ions , to achieve zero background. Thus, the aptasensor with a one-step replacement detection strategy can greatly improve sensitivity, with the detection limit of CEA being 0.333 pg mL −1 . Finally, the stirring bar was employed after introducing the target into the system. Therefore, the whole sample detection time can be reduced to within 10 min. This aptasensor was successfully applied to rapidly and accurately analyze CEA in human serum, with results consistent to those of ELISA . All of these findings prove that this multi-signal amplified, rapid, zero background electrochemical aptasensor can meet the requirements for rapid and highly sensitive detection of tumor markers in human serum.
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