ROOM TEMPERATURE PHOSPHORESCENCE FROM ORGANIC LUMINOPHORES ENGULFED IN DEEP EUTECTIC SOLVENT POLYMERIZED FILM AND ITS MODULATION WITH A PHOTOBASE

ROOM TEMPERATURE PHOSPHORESCENCE FROM ORGANIC LUMINOPHORES ENGULFED IN DEEP EUTECTIC SOLVENT POLYMERIZED FILM AND ITS MODULATION WITH A PHOTOBASE

06/06/2023

Chemistry Faculty Seminar Room

15:30

Ranu Satish Dhale Amdursky’s group, Schulich Faculty of Chemistry, Technion

Physical-Chemistry Seminar

Room temperature phosphorescence from organic luminophores engulfed in deep eutectic solvent polymerized film and its modulation with a photobase

Ranu Satish Dhale

Under supervision of Prof. Nadav Amdursky

Making phosphorescent molecules/materials involves molecular-level engineering. Primarily, making phosphorescent material involves either a confined environment to restrict the molecular vibrations or the inclusion of heavy atoms to generate triplet excited states and facilitate intersystem crossing. However, the design and molecular-level engineering of such phosphorescent material is usually requiring complicated chemical synthesis. Furthermore, in many cases, the synthesized molecules can have poor photostability if stored for a long period and become non-phosphorescent in the presence of oxygen. Here, we demonstrate the fabrication of a room-temperature phosphorescent (RTP) film following a photoinitiated polymerizable deep eutectic solvent approach. Organic luminophores 9-Aminoacridine and 1,8-Naphthalimide are activated to show visible RTP. The constituent of the deep eutectic solvent comprises acrylic acid and tetramethyl ammonium chloride, which create a strong ionic polymeric matrix. In our study, we show that the RTP property of Boron-based dye can be modulated with light irradiation using a photobase: malachite green carbinol base (MGCB). MGCB is an Arrhenius-type photobase that can release a hydroxide ion but only upon light illumination. When the hydroxide attacks the electron deficient boron-based dye, the phosphorescent lifetime is found to decrease, which can be due to ‘unlocking’ the molecules, i.e., a decrease in their rigidity, that affect spin-orbit coupling of the molecules within the film. This study shows a simplified approach to create room-temperature phosphorescent materials, which are stable under ambient conditions together with a suggested mechanism for exploring and modulating their phosphorescent properties using a photobase.