Padmini Pandey

Photoluminescence Quenching in Self‐Assembled CsPbBr3 Quantum Dots on Few‐Layer Black Phosphorus Sheets

An ordered self-assembly of CsPbBr3 quantum dots (QDs) was generated on the surface of few-layer black phosphorus (FLBP). Strong quenching of the QD fluorescence was observed, and analyzed by time-resolved photoluminescence (TR-PL) studies, DFT calculations, and photoconductivity measurements. Charge transfer by typeu2005I band alignment is suggested to be the cause of the observed effects.

Variable excitation wavelength photoluminescence response and optical absorption in BiFeO 3 nanostructures

In this paper we present uniformly distributed ~100xa0nm BiFeO3 nanoparticles synthesized by conventional chemical co-precipitation method in order to scrutinize structural, optical, photoluminescence and dielectric properties. The Rietveld refinement of the X-ray diffraction pattern revealed that the sample is single phase in nature and crystallizes in rhombohedral structure with R3c space group. The average crystallite size and particle strain were estimated by using Debye–Scherer’s and Hall–Williamson method. The particle size of the BiFeO3 nanoparticles is ~100xa0nm with uniform size distribution predicted by the field-emission scanning electron micrographs. The effective band-gap of the nanostructures calculated as 2.74xa0eV along with additional defect levels determined by plotting Tauc relation. The Photoluminescence response of BiFeO3 nanoparticles is extensively observed across the UV–Visible spectrum by illuminating the sample with different excitation wavelengths from ~280 to ~360xa0nm. Photoluminescence also specifies the characteristic band-gap of crystalline BiFeO3 ~2.96xa0eV, along with some prominent energy levels near the conduction and valence band edge that may appear due to nano-structuring. The chemical bonds between the constituent elements of the specimen are traced with FTIR spectroscopy. The dielectric study identifies low frequency dispersive nature of the specimen.