Thin film properties of tetracyanoquinodimethane (TCNQ) with novel templating effects

Abstract

The morphological and structural properties of films based on the strong electron acceptor molecule,7,7,8,8, are presented and the influence of growth rate and the nature of the substrate are investigated. On weakly-interacting substrates, TCNQ films grown by Organic Molecular Beam Deposition (OMBD) exhibit randomly oriented micron-sized islands with significant curvature and three preferential orientations suggested by diffraction from (022), (021) and (020) planes.Pre-coating with 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) is shown to result in morphological and structural modifications to the TCNQ films, characterized by uniform rectangular-shaped micronsized islands, with the preferential molecular orientation reduced to only (020), compared to the films on bare substrates. We rationalise the interactions between TCNQ and PTCDA based on the match between the displacement of the perylene-H atoms/anhydride groups in PTCDA and that of the CN groups in TCNQ. These results suggest an alternative approach for using templating to control the molecular orientation in organic heterostructures.

Comparison of organic and inorganic layers for structural templating of pentacene thin films

“…This new mechanism should significantly broaden the range of orientations that can be obtained in molecular thin films, especially considering that quadrupole intermolecular interactions are dominant in a wide range of functional aromatic molecules. 62,63 Our findings complement previous templating mechanisms, including π-π interactions 25,65 , hydrogen bonds 66 and charge transfer 16 , which have been found to be ineffective with pentacene.…”

Formation of ferromagnetic molecular thin films from blends by annealing

“…Once the tube is pumped down and flushed with nitrogen at a flow rate of 150 sccm for at least one hour the furnace is set to 270 °C and left dwelling for one hour after the final temperature is reached. During this process the TCNQ molecules can slowly escape the film due to their low sublimation temperature of approximately 100 °C [ 15 ].…”

Asymmetric N-heteroacene tetracene analogues as potential n-type semiconductors

“…For OFETs, the addition of an octadecyltrichlorosilane (OTS) self-assembled monolayer or 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) pre-coating on the FET interface is a useful approach to ease charge injection, control molecular packing, and ultimately improve device efficiency. 46,47 Finally, we could look to explore alternative deposition methodologies such as spin coating followed by a program of annealing.…”