Quantum dots (QDs) are semiconductor nanocrystals whose size-dependent optoelectronic properties make them an effective platform for introducing nanoscale concepts in chemistry education. However, direct QD size characterization typically relies on advanced instrumentation that is rarely available in teaching laboratories. This work presents an accessible educational activity for estimating QD size using digital images, including those acquired with a smartphone, are analyzed using a standalone software application executed on Windows or Linux systems to estimate emission wavelength and quantum dot size. The application extracts RGB values from digital images, converts them into approximate emission wavelengths, and estimates QD size using a simplified physical model based on the Brus equation. Although CdTe quantum dots are used as an illustrative example, the software has been expanded to accommodate different quantum dot materials for instructional use. The activity was implemented with 23 undergraduate students from a nontechnical program using a pretest and post-test design. Results indicate learning gains in students’ conceptual understanding of the relationship between QD size, emission wavelength, and band gap energy, along with increased awareness of approximation and model limitations. Overall, this contribution demonstrates how low-cost digital tools can support meaningful engagement with nanoscience concepts in chemistry education.
Reyes et al. (Fri,) studied this question.