Pushing the Efficiency Limits of Solar Cells with Molecular Photon Upconversion
Professor Kenneth Hanson (Florida State University, Dept. of Chemistry & Biochemistry)
Host: Professor Michael Therien
Thursday, February 1, 2018 - 11:40am to 1:10pm
Location: French Family Science Center 2237
Rosenthal, Janet

Link for Professor Hanson

Abstract:  Photon upconversion—combining two or more low energy photons to generate a higher energy excited state—is an intriguing strategy for increasing the maximum theoretical solar cell efficiencies from 33% to greater than 43%. In this presentation we will introduce self-assembled multilayers of sensitizer and acceptor molecules on nanocrystalline metal oxide films as a new structural motif for facilitating molecular photon upconversion via triplet-triplet annihilation (TTA-UC) and directly extracting charge from the upconverted state. Under light intensities as low as ambient solar flux we demonstrate a more than four-fold increase in the short circuit current relative to the sum of the sensitizer and acceptor monolayer devices. We will discuss the dynamics events during TTA-UC, limitations of the current film, and strategies for increasing the TTA-UC efficiency and device performance.