Recent Trend in the Measurements of Luminescence Spectra and Quantum Yields of Metal Complexes

摘要

In a luminescent metal complex, the singlet excited state readily converts the excitation energy to the triplet state by increasing the spin-orbit coupling due to the presence of a heavy atom such a metal ion. The emission is called phosphorescence, which can be frequently observed even at room temperature. This review indicates the problems that inorganic chemists may confront while measuring the emission spectra and the emission quantum yields of metal complexes and introduces the IUPAC project to prepare the guidelines for the measurements. Common textbooks in photochemistry usually aim at the physical and/or organic chemists, and they are not always suitable for inorganic chemists who measure the room-temperature phosphorescence. This review describes the procedures for measuring the emission spectra and the quantum yields of the metal complexes in solution from the viewpoints of selection of solvent, sample concentration, de-aeration, and temperature control. It describes both the relative and absolute methods to determine the emission quantum yields. It further indicates that the measurements of solid-state samples are much more difficult than solutions and recommends that the experimental conditions are reported in as much details as possible.