Local Light Field Regulation And Application Of Perovskite Quantum Dot Luminescence

Perovskite quantum dots have received attention due to their large absorption cross section,high emission efficiency,high carrier mobility and tunable bandgap energy covering the entire visible spectrum of 410-700 nm.These advantages make them be widely used in sensors,detectors,lighting displays,and solar cells.The great advances on ultraviolet(UV)photodetectors have been made based on commercial silicon and inorganic wide bandgap semiconductors,but achieving high UV sensitivity,response time and visible-blind photodetection still remains a challenge.Blue perovskite nanocrystals CsPbCl3 could be an ideal kind of materials for UV photodetectors owing to its excellent band gap,however,limited by its photo-acoustic process.Here,we first explored the luminescent enhancement of CsPbCl3 quantum dots by coupling with Ag plasmon and photonic crystals.Consistently with the theoretical simulation,when the plasmon peak of Ag film and photonic stop band of polymethyl methacrylate(PMMA)opal photonic crystals(OPCs)matched well with the emission peak of blue CsPbCl3 quantum dots,the fluorescence enhancements of about 50 fold and 20 fold were obtained,owing to the collective effect of the excitation and emission field enhancement.Then,the plasmonic photonic crystals were designed through inlaying silver nanoparticles into the apertures of three-dimensional PMMA opals.Through the combination of surface plasmon and photonic crystal effects,the luminescent intensity of CsPbCl3 quantum dots in CsPbCl3/Ag/OPCs hybrids was boosted more than 150 folds with the estimated emission efficiency of 51.5%.Furthermore,the high performance flexible UV photodetector was constructed employing CsPbCl3/Ag/OPCs hybrids.It is with extremely low dark current of 10-11A,high detectivity of 9×1014 J,short response time of 28 ms/31 ms and narrow response line width of 30 nm,which is much better than the commercial silicon photodetectors.This work provides a helpful approach to improve the luminescence/perfermance of perovskite quantum dots and UV photodetectors.Lead ion is one of the most toxic metallic pollutants.Until now,the various detection technology for lead ions detection in water systems were widely explored and developed.However,the Pb2+ ions in oil-soluble environment is limited in the inductively coupled plasma mass spectrometry,atomic absorption spectrometry,seriously lacking of the convenient and cheap detection method.In this work,the lead free perovskite CsSnX3(Cl,Cl/Br,or Br)quantum dots were employed as a novel fluorescent probe for the detection of lead ion in the oily products,with high sensitivity and high selectivity.The highly enhanced photoluminescence,the red shift and the reducing of the full wavelength at half maximum of emission spectra of CsSnX3(Cl,Cl/Br,or Br)quantum dots were observed after adding Pb2+ ions,originating from the subscription of Sn2+ by Pb2+ ions in situ.A wide probing window ranging from 1 X 10-8 M to 1×10-2 M and a low probing limit of 3.5×10-9 M were obtained.Finally,the CsSnBr3 quantum dots was successfully employed to probe Pb2+ions in mask,hair dye,nail polish and oil paint.Our probe provides a promising device to detect Pb2+ ions in organic solution systems.