Soluble Ruthenium Phthalocyanines as Semiconductors for Organic Thin-Film Transistors

Ruthenium phthalocyanine (RuPcs) are multipurpose compounds characterized by their remarkable reactivity and photoelectronic properties, which yield a broad synthetic scope and easy derivatization at the axial position. However, RuPcs have been underexplored for use in organic thin-film transistors (OTFTs), and therefore new studies are necessary to provide basic insight and a first approach in this new application. Herein, two novel RuPc derivatives, containing axial pyridine substituents with aliphatic chains (RuPc(CO)(PyrSiC6) (1) and RuPc(PyrSiC6)2 (2), were synthesized, characterized, and tested as the organic semiconductor in OTFTs. RuPc thin-films were characterized by X-ray diffraction (XRD), and atomic force microscopy (AFM) to assess film morphology and microstructure. 1 displayed comparable p-type device performance to other phthalocyanine-based OTFTs of similar design, with an average field effect mobility of 2.08x10-3 cm2 V-1 s-1 in air and 1.36x10-3 cm2 V-1 s-1 in nitrogen, and threshold voltages from -11 V to -20 V. 2 was found to be non-functional as the semiconductor in the device architecture used, likely as a result of significant differences in thin-film formation. The results of this work illustrate a promising starting point for future development of RuPc electronic devices, particularly in this new family of OTFTs. Ruthenium phtalocyanines (RuPcs) possess distinct photoelectronic properties and a broad synthetic scope allowing for highly tuneable molecular designs, making them promising candidates as organic semiconductors in OTFTs. However, RuPcs have been underexplored in this field, and more studies are needed to provide basic insight into their potential. Herein, two novel RuPc derivatives were synthesized and implemented in OTFTs displaying p-type device operation.+image

Automated summary

This article discusses the synthesis and implementation of two novel ruthenium phthalocyanine derivatives in organic thin-film transistors (OTFTs). One derivative showed promising performance, while the other did not. This study provides a promising starting point for the future development of ruthenium phthalocyanine electronic devices.