Polymer Photonics for Thermal Management

Overview. The thesis will be structured in six different chapters: • Chapter 1 will briefly introduce the topic of distributed Bragg reflectors and will serve as a general theoretical introduction to Chapters 2, 3 and 6, as well as parts of Chapters 4 and 5. The general theory presented can be found on many books on the topic – Saleh’s Fundamentals of Photonics, Giusfredi’s Manual of Optics, Hecht’s Optics, and especially MacLeod’s Thin Film Optical Filters to cite some – but the data reported are calculated with codes developed by me over the years. • Chapter 2 will introduce the problem of excessive heating, the use of air conditioning and the challenges of managing temperature of indoor environments in a warming climate. The work on aegises for thermal management will be presented, intended as distributed Bragg reflectors reflecting near-infrared radiation. In the chapter, the first instances of this kind of structures are designed, reported, characterized and tested for thermal shielding, achieving promising results. The data presented were published in Lanfranchi et al., ACS Appl. Mater. Interfaces 2022, 14, 12, 14550. • Chapter 3 will continue the same line of research, following the results reported in Lanfranchi et al., Chem. Eng. Sci. 2024, 283, 5, 119377. The chapter will delve deeper into the topic of all-polymer aegises, providing a complete design rationale, followed by an exploration of the different materials that can be used and their influence on the thermal shielding performances with a complete characterization of the samples. • Chapter 4 will transition from thermal shielding to radiative cooling, providing a different example of passive thermal management. The focus will be on the challenges of the research field, the building of a quantitative model to describe the phenomenon as well as reporting the results achieved so far with various measuring setup and structures. All data reported are unpublished. • Chapter 5 reports the results I obtained during my period abroad, while I was working on the assembly of an external cavity laser setup by Prof. Benea-Chelmus at École Polytechnique Fédérale de Lausanne (CH). The workflow for the assembly of the setup in its iterations, the characterization of the parts and the final results will be presented. All the data reported are unpublished. • Chapter 6 will briefly report the results of all the collaborations and side projects I worked on during this years. Most of them will be published results (Megahd et al., ACS Omega 2024, 7, 18, 15499; Mater. Chem. Frontiers 2022, 6, 17, 2413; Benvenuti et al., J. Mater. Chem. C 2024, 12, 12, 4243; Magnasco et al., ACS Omega 2024, 9, 41, 42375; Martusciello et al., ACS Appl. Mater. Interfaces 2024, 16, 38, 51384; Baouch et al., Add. Manufactur, 2024, 83, 31, 104063), with few relative to work in preparation (Martusciello et al., submitted 2024, Di Fonzo et al., in preparation). • Appendices contain the Fresnel coefficients (A.1), a thorough description of transfer matrix method (A.2) and additional details on experimental procedures (B.1).