Role of Hot-Injection Technique for the Synthesis of Phase-Pure Kesterite CZTS Nanocrystals for Biosensing Applications

Main Focus in this present work, is biosensing application of CZTS nanoparticle instead of established and mainstream photovoltaics application. Here, biocompatible CZTS have been synthesized using butylamine. The capping effect has been explored in two ways first, post synthesis ligand exchange from TOPO-capped CZTS (Ex-situ) and during synthesis (In-situ). The sample obtained after ex-situ ligand exchange was analysed for its stability using x-ray diffraction method (XRD), transmission electron microscopy (TEM) and photoluminescence (PL) spectroscopy. It has been found that the original kesterite structure was distorted during Ex-situ ligand exchange. However, the In-situ synthesized butylamine capped CZTS were observed to be pure kesterite phased, spherical shaped nanoparticles with enhanced bandgap of 2.65 eV desirable for sensing applications. These nanoparticles were then explored for glucose-sensing application using PL-quenching method. Glucose sensing was further confirmed by fabricating bioelectrode glucose oxidase/CZTS/ITO/glass. The electrochemical analyses of this bioelectrode was done and found to exhibits a good linearity over a wide range of 0-200 μM glucose concentration.