Semi-conductive materials are used in a variety of electrical applications, including perovskite solar cells. A solar cell utilizes positive and negatively-doped layers that, when a current is applied, will allow electrons to flow despite a reverse bias present. These solar cells can be modified so that the current which flows through them is tunable, allowing for modular solar cells which can be applied to a variety of materials. One way to modify these solar cells is to use what is called a hole-transport material, which enables holes left over by an electron to move through the material. For perovskite solar cells the historic hole transporting material is a Spiro-complex called Spiro-MeOTAD. These complexes have been of special interest for optoelectronics and photodiode systems due to their chemical properties and the ease with which they can be synthesized.<br/>This experiment was designed to synthesize a model system of these Spiro-complexes by focusing on making a variety of 9-fluorenone compounds. The 9-fluorenone compound has produced the highest yield of Spiro-compounds when compared to various other ketones that have been examined. The 9-fluorenone complex has been modified by the addition of bromine, nitro, or other constituent groups in order to see how the addition of these compounds will change the chemical properties of the system. With the addition of these ligand groups there is a visible shift of peaks downfield which is due to the addition of electron-withdrawing groups.<br/>The ketone 9-fluorenone was modified by adding bromine or nitro substituents via reaction with bromine or nitric acid, respectively. The product from this reaction was then combined with two equivalents of α-naphthol using an acid catalyst, in most cases this is phosphoryl chloride. These reactions were then conducted using a microwave to heat the reaction system and shorten the reaction time. The final Spiro-complex was then analyzed using NMR, UV-Vis and fluorescence spectroscopy, along with crystallography to confirm the structure of the product.<br/>The purpose of this experiment was to better understand the synthesis of these Spiro-complexes so that more complex Spiro-complexes may be synthesized for material applications.

Spiro synthesis for uses in perovskite solar cells

255th National Meeting (2018)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.