In fact, the study of the films has displayed some complexities, and characteristics such as degree of crystallinity, polymorphism, morphology and molecular orientation at the solid interface, which all contribute to regulate the transport properties of a material, are far from being well understood.
In-depth studies of the structural and morphological characteristics of films of this material, also as a function of the deposition parameters, are therefore urgent to understand the growth processes and to improve the electrical performances of indigo-based devices.Īs a pigment, indigo is highly insoluble in most solvents, a feature which makes the fabrication of the thin films by wet deposition methods difficult and dry physical deposition processes are usually preferred.
On the contrary, not much effort has been spent on the mechanisms of indigo film growth, so the correlation between film morphology/crystallinity and charge transport is relatively unknown. For most of the above OSCs, with pentacene taken as a typical case, growth parameters and electrical performances of devices have been investigated and correlated in detail. However, its OTFT mobility is still remarkably lower than that of best performing systems,, , which include rubrene, pentacene, substituted pentacenes, perylene diimide, , and thienoacene derivatives, and for actual applications it must be increased. Indigo has been shown to be a promising biocompatible semiconductor in OTFTs,, ,, , ] with a bandgap of 1.7 eV, well-balanced electron and hole mobilities of 1 × 10 −2 cm 2 V − 1 s − 1 and good stability of the hole transport against degradation in air. The vat dye indigo (Fig. 1) holds the characteristics of both being an intrinsically ambipolar organic semiconductor and having a natural origin, even though its mobilities have not been measured yet in single crystal. Widespread applications, unfortunately, are currently hampered by the narrow choice of available compounds. Thus, bio-inspired OSCs, which hold the promise of being environmentally friendly and of special relevance for bio-applications, have already been tested in organic thin film transistors (OTFTs),, , ] demonstrating interesting properties.Ī much sought-after property in these systems is a balanced ambipolar charge transport, which is essential for the development of integrated microelectronic circuits and optoelectronic devices.
The wide range of potential uses and the commercial success of organic semiconductors (OSCs), combined with the increasingly urgent issue of eco-compatibility, has stimulated the search for nontoxic, biodegradable, and biocompatible compounds also in this field. At the same time, research in the field of organic semiconductor-based devices has grown extensively and has led to mature OLED technology as well as to highly promising applications in Organic Photovoltaics (OPV), , and Organic Field Effect Transistors (OFETs). In modern science and technology of nanomaterials, interest in biological and bio-inspired systems is motivated by their potential for biomedical integration and sustainable development.
0 kommentar(er)
