Reddish-orange luminescence enhancement via Li+ co-doping in Sm3+ doped Bi2O3 nano-sheets

This paper presents a report on the correlation between structural, morphological, and luminescence properties of a series of Sm3+ (1–7 mol %) doped and Li+ (0.5–3 mol %) co-doped Bi2O3 nano-sheets synthesized via co-precipitation method. The X-ray diffraction (XRD) study ascertains monoclinic phase of the prepared samples. Average crystallite size and strain values have been estimated using Debye-Scherrer and Williamson-Hall methods, which exhibits an improved crystalline nature and reduced strain upon Li+ co-doping. X-ray photoelectron spectroscopy (XPS) has been carried out to explore the chemical composition and oxidation state of the elements present in the sample surface. The UV–Vis spectroscopy has been implemented to investigate the band gap of the samples. A slight increment is observed in the band gap upon doping as well as co-doping. An excitation wavelength of 481 nm has been used to explicate the photoluminescence (PL) emission studies over the range of 540–740 nm. Two-fold enhancement in the emission intensity of the Li+ co-doped samples has been recorded as compared to the Sm3+ doped Bi2O3 samples which make them worthy to be served as exquisite candidates to realize efficient warm white light emitting diodes (wLEDs).