Sub‐Microsecond Molecular Thermometry Using Thermal Spin Flips

The application of platinumporphyrin (an organic semiconductor) as a sensitive molecular thermometer is demonstrated. The instantaneous temperature controls the rate of reverse intersystem crossing after optical population of the triplet, so the ratio of triplet-to-singlet emission provides a measure of temperature (see Figure). Sudden electrical heating of a metallic electrode is monitored with sub-microsecond accuracy, providing input to display design considerations.