Title Influence of fluoro and methyl groups in organic photoconductors containing fluorenyl and carbazolyl chromophores /
Translation of Title Fluor- ir metilgrupių įtakos fluorenilo ir kabazolilo chromoforus turinčių organinių fotopuslaidininkių savybėms tyrimas.
Authors Tiažkis, Robertas
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Pages 61
Keywords [eng] hole transporting material ; perovskite solar cell ; methyl and fluoro groups
Abstract [eng] The molecular structure of hole transporting materials (HTMs) play an important role in hole extraction in perovskite solar cells. It has significant influence on molecular planarity, energy level, and charge transport properties. Understanding the relationship between the chemical structure of HTMs and perovskite solar cells (PSCs) performance is crucial for the continued development of efficient organic charge transporting materials. Using a molecular engineering approach we have constructed a series of hole transporting materials with strategically placed aliphatic substituents to investigate the relationship between the chemical structure of the HTMs and the photovoltaic performance. PSCs employing the investigated HTMs demonstrate power conversion efficiency values in the range of 9% to 16.8% highlighting the importance of optimal molecular structure. An inappropriately placed side group could compromise the performance of the device. Due to ease of synthesis and moieties employed in its construction, it offers a wide range of possible structural modifications. This class of molecules has great potential for structural optimization in order to realize simple and efficient small molecule based HTMs for perovskite solar cell application. One of the main problems of PSCs is hygroscopicity of the perovskites which determines the transiency of the cells. The second part of this project was to synthesize HTMs which would be more moisture resistant. Because of the unique characteristics of the fluorine atom we decided to construct materials which would have a similar structure to the conventional ones and replacing one or several hydrogen atoms with fluorine atoms. After measuring the wetting angle of the materials we found out that the addition of a fluorine atom in a molecule increased the hydrofobicity of the material almost in all cases. Based on these results we can assume that a strategic addition of fluorine atoms to a HTM could increase the operation time of a PSC.
Dissertation Institution Kauno technologijos universitetas.
Type Master thesis
Language English
Publication date 2017