Abstract
In the organic electronics research field, several strategies have been used to modulate the transport properties of thiophene-derived semiconductors via sequential functionalization of their π-conjugated cores. This review summarizes the major design and synthetic strategies for tuning thiophene-containing small molecule and polymer properties by introducing electron-deficient nitrogen-containing azine and azole moieties. Several examples are presented which elucidate the structural, optical, and electronic consequences of incorporating these electron-deficient fragments in the conjugated skeletons, particularly relating to applications in organic thin-film transistors.
Highlights
General OverviewOver the last few years, thiophene-based small molecules and polymeric semiconductors [1] have attracted increasing attention for applications in diverse opto-electronic devices, such as organic fieldeffect transistors (OFETs) [2,3,4,5,6], light-emitting diodes [7,8], lasers [9], sensors [10,11], and photovoltaic cells [12]
Since highest occupied molecular orbital (HOMO) energy reduction is usually accompanied by a lowering of the lowest unoccupied molecular orbital (LUMO) level as well, n-channel or ambipolar transport materials should be possible
The absence of electron transport was explained by the authors on the basis of: (i) the presence of electron trap centers originating from chemical groups on the dielectric surface; (ii) the localization of the lowest unoccupied molecular orbital (LUMO) of the polymer on the electron-accepting part of the molecule (Figure 13)
Summary
Over the last few years, thiophene-based small molecules and polymeric semiconductors [1] have attracted increasing attention for applications in diverse opto-electronic devices, such as organic fieldeffect transistors (OFETs) [2,3,4,5,6], light-emitting diodes [7,8], lasers [9], sensors [10,11], and photovoltaic cells [12]. Device performance has been optimized by perfecting film growth processes using selected solvents, deposition temperatures, solvent or thermal annealing processes, and/or pairing with semiconductor properties-enhancing gate dielectrics [30,31,32] Another strategy, which will be discussed in detail in this review, includes oligothiophene core functionalization with nitrogen-containing, electron-poor heterocycles. Recent experimental and theoretical results have demonstrated that oligothiophene molecular electronic structure and FET majority charge transport properties respond in very different, and not necessarily intuitive ways to semiconductor skeletal modifications [40] These observations highlight the importance of analyzing the results obtained so far in order to better understand the structural and electronic effects of introducing azine and/or azole rings in thiophene-containing small molecules and polymers. The electronic structure and the electrical performance of azine- and azolesubstituted oligo- and polythiophene semiconductors will be discussed
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
