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Photodegradable MEH-PPV in a natural rubber matrix: Toward a biocompatible colorimetric film for real-time light dosimetry
摘要： This paper reports an interesting strategy of incorporating a photodegradable polymeric luminophore, the poly [2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] - OC10C6-PPV (MEH-PPV), in an inert natural rubber (Hevea brasiliensisis) - C5H8 (NR) matrix for monitoring and recording the radiation dose administered to patients under phototherapy, particularly in the treatment for jaundice newborns. A time-trend spectro?uorimetric study has been carried out to characterize the luminescent changes of the MEH-PPV/NR luminophore system upon photodegradation by realistic conditions of phototherapy treatment, and the dependence between color and dose was used to determine the dose-response relationships of this color ?lm dosimeter. Cytotoxicity tests (CHO-K1 cell line) have also been conducted on extracts of the OC10C6-PPV/C5H8 before and after photolysis. The experimental results reported here highlight the potential application of photodegradable polymer/natural rubber as a biocompatible skin-mountable patch to monitor light exposure to improve patient care in phototherapy, photodynamic, lasers and radiation therapies.
关键词： Medical-devices,Dosimeter,Printable device,Photooxidation,Organic device,Semiconducting polymer,Radiation oncology
更新于2025-11-14 15:18:02
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Oxygen-vacancies-engaged efficient carrier utilization for the photocatalytic coupling reaction
摘要： Defects can greatly optimize the solar light harvesting capability and electronic structure of oxide materials. However, it remains challenging to achieve a defect engineering strategy under mild conditions. Meanwhile, the simultaneous exploitation of photogenerated holes (h+) and electrons (e?) to promote both photooxidation and photoreduction in a coupled system has rarely been reported. For the first time, we reveal an oxygen-vacancies-mediated photocatalytic strategy in which the electrons and holes are fully utilized for nitrobenzene reduction coupled with benzyl alcohol oxidation. The oxygen vacancies (OVs) generated in situ on the surface of TiO2 greatly extend light absorption into the visible region and promote the photogenerated electron transport for efficient photocatalysis. The experimental and theoretical results together indicate that chemisorption on the TiO2 surface decreases the oxidation potential of benzyl alcohol and causes an upward shift in its HOMO, which facilitates the oxidation reaction of benzyl alcohol to benzaldehyde. The in situ generated surface OVs also act as a bridge to enable the trapping and transferring of the photoinduced electrons to the nitrobenzene. This work provides a new perspective of utilizing the chemisorption between the reactant and catalyst to achieve a defect engineering strategy for synergetic photocatalysis.
关键词： Photocatalysis,Photoreduction,Surface complexation,Oxygen vacancies,Photooxidation
更新于2025-11-14 14:48:53
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Hydrophobic Metal Halide Perovskites for Visible-Light Photoredox C-C Bond Cleavage and Dehydrogenation Catalysis
摘要： Two-dimensional lead and tin halide perovskites were prepared by intercalating the long alkyl group 1-hexadecylammonium (HDA) between the inorganic layers. We observed visible-light absorption, narrow-band photoluminescence, and nanosecond photoexcited lifetimes in these perovskites. Due to their hydrophobicity and stability even in humid air, we applied these perovskites in the decarboxylation and dehydrogenation of indoline acids using (HDA)2PbI4 or (HDA)2SnI4 as photoredox catalysts, with quantitative conversions and high yields for the former. We highlight another original application of the metal halide perovskites.
关键词： photocatalysis,2D metal halide perovskites,decarboxylation,photooxidation,hydrophobic perovskite
更新于2025-09-23 15:23:52
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Hydrophobic Metal Halide Perovskites for Visible-Light Photoredox C-C Bond Cleavage and Dehydrogenation Catalysis
摘要： Two-dimensional lead and tin halide perovskites were prepared by intercalating the long alkyl group 1-hexadecylammonium (HDA) between the inorganic layers. We observed visible-light absorption, narrow-band photoluminescence, and nanosecond photoexcited lifetimes in these perovskites. Due to their hydrophobicity and stability even in humid air, we applied these perovskites in the decarboxylation and dehydrogenation of indoline acids using (HDA)2PbI4 or (HDA)2SnI4 as photoredox catalysts, with quantitative conversions and high yields for the former. We highlight another original application of the metal halide perovskites.
关键词： photocatalysis,2D metal halide perovskites,decarboxylation,photooxidation,hydrophobic perovskite
更新于2025-09-23 15:22:29
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Photooxidation of cyclohexene in the presence of SO<sub>2</sub>: SOA yield and chemical composition
摘要： Secondary organic aerosol (SOA) formation from cyclohexene/NOx system with various SO2 concentrations under UV light was studied to understand the effects of cyclic alkenes on the atmospheric environment in polluted urban areas. A clear decrease at first and then increase of the SOA yield was found with increasing SO2 concentrations. The lowest SOA yield was obtained when initial SO2 concentration was in the range of 30-40 ppb, while higher SOA yield compared to that without SO2 could not be obtained until the initial SO2 concentration was higher than 85 ppb. SOA formation was enhanced by the acid-catalyzed heterogeneous reactions, which lead to an increase in the total organic aerosol mass. The competitive reaction of OH radicals with SO2 and VOCs was the reason for the SOA yield decrease even under acidic conditions. The competitive reaction was an important factor for SOA yield and it should not be neglected in photooxidation, especially when acid-catalyzed mechanism could not significantly improve SOA yield. The composition of organic compounds in SOA was measured using several complementary techniques including Fourier transform infrared (FTIR) spectrometer, ion chromatograph (IC) and electrospray ionization high-resolution quadrupole mass spectrometer (ESI-HR-MS). We present the first evidence that organosulfates were produced from the photooxidation of cyclohexene in the presence of SO2.
关键词： organosulfates,SO2,SOA,photooxidation,cyclohexene
更新于2025-09-23 15:19:57
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Diastereoselective Photooxidation and Reduction of Chiral Iridium(III) Complexes
摘要： A diastereoselective photooxidation of α-amino acid (AA) complexes into imino acid complexes using a chiral iridium(III) complex as a photosensitizer and stereo-controller under visible light irradiation and oxygen was developed. It was found that the oxidative rate of Δ-[Ir(pq)2(L-AA)] (pq is 2-phenylquinoline) diastereomer is significantly higher than that of the corresponding Δ-[Ir(pq)2(D-AA)] diastereomer, providing a new protocol for kinetic resolution of AAs via a nonenzymatic pathway. Moreover, the thermodynamic controlled strategy offered a complemental method for the diastereoselective hydrogenation of imine bonds using NaBH4 as a reductant under the chiral Ir(III) complex as a stereo-controller. The combination of diastereoselective photooxidation and reduction processes results in a new protocol for deracemization of α-amino acids under mild conditions. Mechanism study strongly indicates that singlet oxygen is a key participant in the reaction and the α-C?H bond cleavage of AAs is the rate-determining step.
关键词： kinetic resolution,diastereoselective photooxidation,chiral iridium(III) complex,deracemization,α-amino acids
更新于2025-09-23 15:19:57
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Suppressing Effect of 2-Nitrobenzaldehyde on Singlet Oxygen Generation, Fatty Acid Photooxidation, and Dye-Sensitizer Degradation
摘要： 2-Nitrobenzaldehyde was found to efficiently block singlet oxygen generation in a series of different test samples upon exposure to UV and visible light under aerobic conditions. The effect of quenching singlet oxygen formation was monitored in the presence of 1, 4-diazabicyclo [2.2.2] octane (DABCO) acting as a well-known singlet oxygen scavenger. A comparison of different nitrobenzaldehyde isomers with other highly effective synthetic antioxidants used in the food industry such as butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), tert-butylhydroquinone (TBHQ) revealed that the protection of materials from singlet oxygen decreases in the order of 2-nitrobenzaldehyde > DABCO > TBHQ > 3-nitrobenzaldehyde > BHA > 4-nitrobenzaldehyde > BHT. Upon addition of 2-nitrobenzaldehyde, the oxidation of fatty acids and the degradation of photosensitizers was found to be considerably diminished, which indicates that the presence of 2-nitrobenzaldehyde has a significant protective influence by restricting the singlet oxygen generation and photodegradation of dyes. Moreover, the compound turned out to display its highly suppressing effects on typical singlet oxygen-dependent reactions, such as fatty acid photooxidation and dye photosensitizer degradation, in a rather broad spectral region covering wavelengths from 300 nm (UV-B) to 575 nm (close to the maximum of ambient solar radiation).
关键词： photostabilization,singlet oxygen scavenger,inhibition of fatty acid photooxidation,UV photoprotection,2-nitrobenzaldehyde
更新于2025-09-19 17:15:36
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Air exposure oxidation and photooxidation of solution-phase treated PbS quantum dot thin films and solar cells
摘要： The air exposure oxidation mechanisms of PbS quantum dot (QD) thin films and solar cells are studied in the current paper. As a novel and advantageous method, QD thin films were prepared by the single-step deposition of colloidal QDs treated with different ligands of butylamine (BA), mercaptopropionic acid (MPA), tetra-butylammonium iodide (TBAI), methylammonium iodide (MAI) and methylammonium lead triiodide (MAPbI3, perovskite). Photoluminescence (PL) measurements evaluated the stability of different surface treated PbS QDs during the colloidal to thin film transformation, and over the air exposure times. Blue-shift and quenching the PL spectra suggested rapid oxidation of QD thin films at the first times of air exposure. However, the oxidation rates significantly reduced for the QD thin films treated with organic MPA and all the inorganic ligands. According to the X-ray photoelectron spectroscopy (XPS) studies, thin films oxidation accompanied with the formation of PbSO3 and PbSO4 compounds on the (100) facets of PbS QDs. Although MAPbI3 treatment led to the complete passivation of QDs in the air, perovskite shelling partially oxidized to PbO and PbCO3 compounds. Furthermore, the PL enhancement phenomenon observed at the first times of air exposure for the TBAI and MAPbI3-treated QD thin films, as a result of their strong surface passivation as well as the photoenhancement and photoelectrification mechanisms. Eventually, p-n and p-i-n structured solar cells were fabricated by the single-step deposition of solution-phase treated PbS QD inks. In this case, inorganic surface treatments not only increased the power conversion efficiency (PCE) of solar cells, but also led to a high stability of fabricated devices in the air environment (lower than 1% PCE loss after 500 h of storage in the air).
关键词： PbS quantum dot,Solar cell,Ligand,Photooxidation,Thin film,Air stability
更新于2025-09-19 17:13:59
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Colorimetric Polymerase Chain Reaction Enabled by a Fast Light-Activated Substrate Chromogenic Detection Platform
摘要： Miniaturization of nucleic acid tests (NATs) into portable, inexpensive detection platforms may aid disease diagnosis in point-of-care (POC) settings. Colorimetric signals are ideal readouts for portable NATs, and it remains of high demand to develop color readouts that are simple, quantitative and versatile. Thus motivated, we report a Fast Light-Activated Substrate cHromogenic polymerase chain reaction (FLASH PCR) that uses DNA intercalating dyes (DIDs) to enable colorimetric nucleic acid detection and quantification. The FLASH system is established on our finding that DID-DNA intercalation can promote the rapid photooxidation of chromogenic substrates through light-induced production of singlet oxygen. Using this principle, we have successfully converted DID-based fluorescent PCR assays into colorimetric FLASH PCR. To demonstrate the practical applicability of FLASH PCR to POC diagnosis, we also fabricated two readout platforms, including a portable electronic FLASH reader and a paper-based FLASH strip. Using the FLASH reader, we were able to detect as low as 60 copies of DNA standards, a limit of detection (LOD) comparable with commercial quantitative PCR. The FLASH strip further enables the reader-free detection of PCR amplicons by converting the colorimetric signal into the visual measurement of distance as a readout. Finally, the practical applicability of the FLASH PCR was demonstrated by the detection and/or quantification of nucleic acid markers in diverse clinical and biological samples.
关键词： FLASH,Singlet Oxygen,Photooxidation,DNA Intercalating Dyes,Colorimetric,Nucleic Acid Tests,Paper-based Strip,Point-of-Care,Portable Electronic Reader,Polymerase Chain Reaction
更新于2025-09-19 17:13:59
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One-pot synthesis of Mn3O4-coupled Ag2WO4 nanocomposite photocatalyst for enhanced photooxidative desulfurization of thiophene under visible light irradiation
摘要： The photooxidative desulfurization of thiophene (ThP) becomes a challenge in both industry and environmental remediation. Herein, we synthesize a visible-light-responsive Ag2WO4/Mn3O4 nanocomposite by a one-pot strategy. Depiction of the produced photocatalysts exposed the suppression of the surface structure and reduction of the bandgap energy by adding 15 wt% of Mn3O4 to Ag2WO4. The obtained nanocomposite shows a complete photooxidation of ThP within 1 h under visible light illumination at a dose of 1.2 g L?1. The significance of photocatalytic performance of Ag2WO4/Mn3O4 nanocomposite photocatalyst is referred to the enhancement of the visible light absorption and overthrow of the recombination of photogenerated charge carriers. The study opens the door for extensive use of nanocomposite photocatalysts as a novel functional material for the photooxidation of ThPs under visible light exposure.
关键词： Desulfurization,Photooxidation,Thiophene,Nanocomposite,Photocatalysts,Visible light
更新于2025-09-16 10:30:52