Title: Solar harvesting via transparent thin films of porphyrin compounds for photothermal and photovoltaic dual modality building skins

Biography:

Professor Donglu Shi is the chair of the Materials Science and Engineering program at the College of Engineering and Applied Science, University of Cincinnati. His research deals with the design of nanostructures for fundamental new properties and novel applications in energy and biomedicine. He is a Fellow of ASM International and the Editor in Chief of Nano LIFE. Dr. Donglu Shi has published 300 refereed Journal papers with a Google Scholar h-index of 63.

Abstract

The porphyrinic compounds, such as chlorophyll and chlorophyllin, have been characterized to exhibit strong absorptions near UV and NIR regions that are ideal for solar harvesting. Their high average visible transmittances also make it possible for solar energy applications via energy efficient building skins with the glass facade. We report the synthesis and characterization of chlorophyll and chlorophyllin thin films that are deposited on glass substrates for solar harvesting and energy generation with the PT- and PV dual modality. Various transparent PT films have been coated on single-pane windows for the so-called Optical Thermal Insulation (OTI) without any intervening medium. Upon solar irradiation, the window surface can be heated up by the PT coating, therefore raising the temperature relative to that of the room interior. This will lead to a significant reduction in heat transfer through the window, especially in winter. For warmer seasons, the transparent PT film can be switched to the photovoltaic (PV) mode for production of electricity. We report the experimental results on the spectral-selective chlorophyll and chlorophyllin thin films with the PT- and PV dual modality. Both photothermal heating behaviors and I-V curves are characterized for these transparent thin films. Also discussed are the fundamental photothermal mechanisms associated with the electronic structures of the porphyrin structures