Revealing the influence of steric bulk on the triplet–triplet annihilation upconversion performance of conjugated polymers

A series of poly(phenylene-vinylene)-based copolymers are synthesized using the Gilch method incorporating monomers with sterically bulky sidechains. The photochemical upconversion performance of these polymers as emitters are investigated using a palladium tetraphenyltetrabenzoporphyrin triplet sensitizer and MEH-PPV as reference. Increased incorporation of sterically bulky monomers leads to a reduction in the upconversion efficiency despite improved photoluminescence quantum yield. A phosphorescence quenching study indicates issues with the energy transfer process between the triplet sensitizer and the copolymers. The best performance with 0.18% upconversion quantum yield is obtained for the copolymer containing 10% monomer with bulky sidechains.

A Novel Phosphorescent Iridium(III) Complex Bearing Formamide for Quantitative Fluorine Anion Detection

Fluorine anion plays a critical role for human health, especially for the teeth and the skeletal system, and a deficiency or excess of fluorine anion will result in various diseases. Thus, the accurate and timely detection of fluorine content is of great importance. Herein, a novel and sensitive fluorine probe based on ionic iridium(III) complex using 5-formamide phenanthroline as an ancillary ligand was designed and synthesized rationally. The probe exhibited excellent performance for F− detection in organic solvents. H-bonding between the fluoride and the amide proton was formed, thus changing the photophysical properties of the probe and leading to significant phosphorescence quenching. Nuclear magnetic resonance titration and theoretical calculations were carried out to understand the mechanism in detail. This is the first report of an iridium(III) complex probe for F− detection based on the interaction between formamide and fluorine anion.

A pilot study of the dynamics of tissue oxygenation in vivo using time-resolved phosphorescence imaging

Oxygenation of tissues plays an important role in the development and progression of tumor to treatment effects. Method of metalloporphyrines phosphorescence quenching by oxygen is one of the ways to measure dynamics of the oxygen concentration in the tissues by phosphorescence lifetime imaging of meso-tetra(sulfopheny1)tetrabenzoporphyrin Pd (II) (TBP) using the time-correlated single photon counting (TCSPC) method. It has been shown that phosphorescence lifetime of the sensor in S37 tumor in vivo varied in the range of 130 to 290 [Formula: see text]s after both topical and intravenous administration of TBP. It indicates that oxygen level in tumors was lower compared to normal tissues where TBP phosphorescence has not been detected. Phosphorescence lifetimes of TBP increased in the solid tumor and in the muscle after photodynamic therapy of solid tumor that demonstrates oxygen consumption during treatment and possibly stopping the blood flow and hence the oxygen supply to the tissues.

A Phosphorescence Quenching-Based Intelligent Dissolved Oxygen Sensor on an Optofluidic Platform

Continuous measurement of dissolved oxygen (DO) is essential for water quality monitoring and biomedical applications. Here, a phosphorescence quenching-based intelligent dissolved oxygen sensor on an optofluidic platform for continuous measurement of dissolved oxygen is presented. A high sensitivity dissolved oxygen-sensing membrane was prepared by coating the phosphorescence indicator of platinum(II) meso-tetrakis(pentafluorophenyl)porphyrin (PtTFPP) on the surface of the microfluidic channels composed of polydimethylsiloxane (PDMS) microstructure arrays. Then, oxygen could be determined by its quenching effect on the phosphorescence, according to Stern–Volmer model. The intelligent sensor abandons complicated optical or electrical design and uses a photomultiplier (PMT) counter in cooperation with a mobile phone application program to measure phosphorescence intensity, so as to realize continuous, intelligent and real-time dissolved oxygen analysis. Owing to the combination of the microfluidic-based highly sensitive oxygen sensing membrane with a reliable phosphorescent intensity detection module, the intelligent sensor achieves a low limit of detection (LOD) of 0.01 mg/L, a high sensitivity of 16.9 and a short response time (22 s). Different natural water samples were successfully analyzed using the intelligent sensor, and results demonstrated that the sensor features a high accuracy. The sensor combines the oxygen sensing mechanism with optofluidics and electronics, providing a miniaturized and intelligent detection platform for practical oxygen analysis in different application fields.

Quenching of the Phosphorescence of Thermally Reversible Photochromic Naphthopyran Re(I) Complexes Initiated by either Visible or Ultraviolet Radiation

Re(I) complexes bearing thermally reversible photochromic naphthopyran axial ligands undergo highly efficient, reversible phosphorescence quenching actuated by either visible or UV irradiation. The photoinduced quenching of the triplet metal-to-ligand charge-transfer...

Optimization of bright, highly flexible, and humidity insensitive porphyrin-based oxygen-sensing materials

There is a strong demand for reliable oxygen sensors in the fields of fitness tracking, health monitoring, and medical diagnostics. Recently, oxygen-sensing materials based on phosphorescence quenching by oxygen have...