Photoprocesses in chemical education. Key experiments for core concepts

Abstract Due to the “big five” challenges in the 21st Century related to the terms of energy, food, water, mobility and climate, mankind has to replace energy from fossil fuels step by step by renewable energies. Between them, solar energy is definitely the most abundant and clean. This is a major, but not the only reason for the inclusion of photoprocesses into chemical education. In this article we present an experimental approach to the basic concept suitable for teaching all phenomena involving light in a reasonable approximation. Updated experiments demonstrating the down conversion of light by fluorescence and room-temperature phosphorescence as well as aggregation induced emission and rigidification induced luminescence are described. In order to use these experiments for teaching basic concepts in photochemistry, a simple version of an energy level model, and an extended version, containing vibrational states, are proposed.