Structural, optical and photoluminescence enhancement of 2-mercaptoacetic acid capped Mn2+ doped CdS nanoparticles and their applications in efficient detection of latent fingerprints

Abstract

CdS:Mn2+ nanoparticles (NPs) stabilized with 2- mercaptoacetic acid (MAA) as a capping agent at different concentrations were developed by co-precipitation method. The X-ray diffraction (XRD) measurement revealed the existence of the cubic phase for stabilized NPs. Scherer’s method, Williamson-Hall (W-H) plot and size-strain plots (SSP) were helpful in the evaluation of the crystallite size and lattice strain of formed products. Ultraviolet–Visible absorption spectroscopy was adopted for energy gap determination, where Tauc’s plots infer that the energy gap increased with the increase in MAA volume percentage. The existence of MAA capping on CdS:Mn2+ was confirmed by fourier transform infrared (FTIR) spectroscopy. The outcome of transmission electron microscopy (TEM) results indicated the presence of spherical shape particles with a typical size of 6–7 nm, which is an encouraging feature for numerous applications. Two emission peaks around 477 nm (blue) and 575 nm (yellow) were observed for MAA stabilized CdS:Mn2+ NPs concerning photoluminescence (PL) spectroscopy. The disintegration and oxidation of the samples in the form of foremost weight loss and gain were studied by thermogravimetric analysis (TGA). Visualization of latent fingerprints (LFPs) under normal light on different porous and nonporous surfaces was conducted in the presence of MAA stabilized CdS:Mn2+ NPs. The acquired emissive fingerprint powder gave superior images with high distinction and resolution connecting the ridges and space. Based on these results, MAA capped Mn2+ doped CdS NPs can be used for the recognition of LFPs in solving criminal cases.

Keywords

• Mn2+ doped CdS
• 2-Mercaptoacetic acid
• XRD
• Band gap tunability
• Photoluminescence
• Latent fingerprint