The short wave near-infrared fluorescence properties of two p-azaquinodimethane (p-AQM)-based conjugated polymers

The absorption,scattering,and autofluorescence of biological tissues in short-wave infrared re-gion(SWIR,900-1700 nm)are relatively low,so SWIR fluorescence usually has deeper pene-tration into living tissues,and can show a higher signal-to-noise ratio when used for imaging in vivo.However,there are few types of organic SWIR fluorescent materials currently.In this work,p-azaquinodimethane(p-AQM)with a quinoid structure is used as the acceptor unit,and car-bazole or fluorene with sp3 hybridization are used as the donor units,two conjugated polymers were synthesized.The quinone structure is conducive to the redshift of absorption and fluores-cence spectra,and the sp3 hybridization structure is conducive to weakening the aggregation quenching of polymer fluorescence.PF and PCz exhibited absorption peaks of 492 nm and 508 nm,respectively.The emission peaks of the two polymers are 920 nm and 950 nm,respec-tively,both in the short-wave near infrared region.The quantum yield(QY)of PF and PCz is 0.4%and 0.3%,respectively.

Ball-milled bismuth oxychloride/biochar nanocomposites with rich oxygen vacancies for reactive red-120 adsorption in aqueous solution

Fabricating surface oxygen vacancies is considered to be an efficient method to improve the adsorption performance of sorbents.In this work,a bismuth oxychloride/biochar(BiOCl/BC)nanocomposite with abundant oxygen vacancies was successfully prepared by a facile ball milling method.BiOCl/BC nanocomposite was found to have excellent adsorption performance for removing reactive red-120(RR120)from aqueous solution.The effects of key adsorption parameters,such as RR120 dye concentration,solution pH(2-10),and contact time were studied by batch adsorption test.The adsorption data were well described by the Langmuir and Freundlich isotherms and pseudo-second-order kinetic models.The 50%-BiOCl/BC(50 wt%of BiOCl in composite)exhibited the best adsorptive performance(60%),much better than the pristine BM-BC(20%).The high adsorption capacity of 50%-BiOCl/BC(Langmuir maximum capacity of 116.382 mg g^(−1))can be attributed to the electrostatic effect,π-πinteractions,and hydrogen bond.This work provided a facile method to prepare semiconductor assisted biochar-based adsorbents,which would also contribute to the advance of environmental remediation.