Light Emission Measurement at Low Temperature

Introduction

Light emission such as fluorescence occurs at transitions from the excited state to the ground state. The efficiency (η) of such emissions is expressed by the following equation based on the ratio of radiative transitions (WR) and non-radiative transitions (WNR). Transitions from the excited state are greatly affected by the surrounding environment and heat has a substantial influence on emissions. Greater influences from heat increase non-radiative transitions, which in turn lowers emission efficiency and results in lower emission intensities. Therefore, to avoid the influence of heat, many measurements are done by lowering the sample temperature such as by using liquid nitrogen. This article introduces measurements of liquid and powder samples cooled down to liquid nitrogen temperature (77 K) using a low-temperature measurement unit combined with the RF-6000 spectrofluorophotometer.

March 12, 2018 GMT