The Synthesis and Transport Properties of Conjugated Molecular Wires

Due to the rapid growth in the electronics industry for over the last century, the demand for more advanced materials has been raised. As a result of this, the number of the scientific studies to develop new type of electronic materials has increased and new fields of research such as molecular electronics and nanotechnology are now established. The trend in the advances in electronics follows the miniaturisation of the electrical components and therefore introducing single or a few molecules into electronic devices has become an important topic. In this work, a summary of the new aspects/developments in the field of single-molecule electronics is presented. Symmetrical tolane compounds with thiol (SH), amino (NH2), pyridyl (Py) and cyano (CN) anchoring groups were synthesised and single-molecule conductances of those molecules were systematically compared. With the help of density functional theory (DFT) calculations, single-molecular junction formation mechanism is also identified. Oligoyne molecular wires with different anchoring groups are also synthesised and their electron transport properties at the single-molecule level are studied. The stability of the functional diaryltetrayne compounds is discussed and X-ray molecular structures of the stable tetraynes are presented. The effects of the molecular length and the anchoring group are discussed in detail. Additionally, oligoynes with methyl shielding of the carbon backbone are synthesised and their stability is discussed. Finally, length-persistent, conjugated OPE and tolane analogues with different molecular lengths and amine anchors were synthesised and their transport properties were investigated in quantum dot sensitised solar cells.