673137 event 1708638756 1708638755 <![CDATA[Ph.D. Dissertation Defense - Oliver Moreno]]> Title:  Organic Molecules with Delayed Fluorescence Applied to Human-centric Lighting and Radiation Detectors

Committee:

Dr. Bernard Kippelen, ECE, Chair, Advisor

Dr. Azad Naeemi, ECE

Dr. Gregory Durgin, ECE

Dr. Canek Hernandez, Northeastern

Dr. Natalie Stingelin, MSE

 

]]> This research explores the class of organic molecules exhibiting thermally activated delayed fluorescence and their application to wavelength-shifting light converters and scintillators through stereolithography. This document begins by establishing the motivation for this work as well as the historical context in the literature. This thesis explores the fundamentals of lighting physics, recent developments in lighting science, and the open challenges rooted in the photophysics of materials. The research program conducted to address those challenges is discussed, resulting in a proposed set of metrics to better benchmark light sources, and a proposed new state-of-the-art light source that is color tunable through correlated color temperature (CCT) values ranging from 4,277 K to 22,333 K with color gamut index Rg values within 3%, IES color fidelity index Rf values within 7% of the natural light reference illuminant. The efficiency metrics pertaining to circadian lighting performance remain within 10% of those of the natural light reference illuminant over the same CCT range. Applications of this light source technology are explored in the context of advancing the state-of-the-art towards fully-3D printed network connected lighting systems that reach power efficiency beyond 390 lm/W. The second half of this thesis focuses on ionizing radiation detection. The basic architectures of detectors for different energies and open challenges in the field are discussed. Advances made towards 3D printable plastic scintillators are discussed, and the performance enhancements resulting from loading the scintillator with molecules exhibiting thermally activated delayed fluorescence and high-Z materials for improved capture cross-section. The application of these scintillators and wavelength shifting-light converters towards detector systems for nuclear nonproliferation systems are highlighted, including monitoring through unmanned vehicles and remote large-volume detectors relevant to particle physics.

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