Quantum Dots in a Polymer Composite: A Convenient Particle-in-a-Box Laboratory Experiment

Semiconductor quantum dots are at the forefront of materials science chemistry with applications in biological imaging and photovoltaic technologies. We have developed a simple laboratory experiment to measure the quantum-dot size from fluorescence spectra. A major roadblock of quantum-dot based exercises is the particle synthesis and handling; the former requires dangerous chemicals while the later can lead to sample degradation. We overcome these drawbacks by using commercially available quantum dots. The samples are composed of CdSe–ZnS core–shell nanoparticles embedded in a polymer matrix. A fluorescence spectrophotometer is used to collect photoluminescence data and the subsequent calculations are straightforward. Student feedback indicates that these experiments provide a new understanding of quantum mechanics and the particle-in-a-box model. We are able to examine the role of spectroscopy in chemical investigations and a cause of spectroscopic line broadening.