Organic Semiconductors for Solution‐Processable Field‐Effect Transistors (OFETs)

Abstract

The cost-effective production of flexible electronic components will profit considerably from the development of solution-processable, organic semiconductor materials. Particular attention is focused on soluble semiconductors for organic field-effect transistors (OFETs). The hitherto differentiation between "small molecules" and polymeric materials no longer plays a role, rather more the ability to process materials from solution to homogeneous semiconducting films with optimal electronic properties (high charge-carrier mobility, low threshold voltage, high on/off ratio) is pivotal. Key classes of materials for this purpose are soluble oligoacenes, soluble oligo- and polythiophenes and their respective copolymers, and oligo- and polytriarylamines. In this context, micro- or nanocrystalline materials have the general advantage of somewhat higher charge-carrier mobilities, which, however, could be offset in the case of amorphous, glassy materials by simpler and more reproducible processing.

Methoxy functionalisation: exerting synthetic control of the supramolecular and electronic structure of nitrogen-doped nanographenes

“…[1][2][3] Although electron mobility remains a challenge, these represent lightweight, flexible alternatives that are more readily processed using solution-based methods. Within this arena, the opportunities proffered by the exceptional electronic and physical properties of graphene and its derivatives are undeniable.…”

Polyethers containing 3,6-diarylcarbazolyl groups as polymeric materials for hole transporting layers of OLEDs

“…Polymers and low-molar-mass materials containing electro-active moieties and capable of thin amorphous film formation are known for various applications such as active layers in organic light emitting diodes (OLEDs), [1][2][3][4][5][6] photovoltaic cells, [7][8][9][10] field effect transistors [11,12] and photorefractive materials. [13,14] Amorphous electro-active layers of polymers can be fabricated using simple techniques.…”

Wet-processed n-type OTFTs utilizing highly-stable colloids of a perylene diimide derivative

“…The problem, however, is that most of small molecular organic semiconductors with high performance are not soluble in common solvent due to their highly conjugated molecular structures and cannot be handled by wet-processes. For that reason, people have tried to use polymers as the active materials utilizing their high solubility [14,15], or to use precursor molecules for the formation of the active film [16][17][18][19], or to synthesis new soluble materials [20][21][22][23][24]. There seems, however, to be performance limits or serious demerits in those approaches although the performance of wet-processed OTFTs has been improved rapidly so far.…”

“…Substitution of solubilizing groups on highly conjugated backbone is usually accompanied by unintended and unfavorable change in molecular-packing pattern by distorting the molecular backbone or by steric hindrance of huge substituents, which results in limited device performance [20][21][22][23][24][28][29][30][31]. Therefore, it is highly desirable to make OTFTs with small molecular organic semiconductors without any molecular modification nor performance decrease using some simple wet-processes.…”