Details

Autor(en) / Beteiligte

• Ozdemir, Resul
• Choi, Donghee
• Ozdemir, Mehmet
• Kwon, Guhyun
• Kim, Hyekyoung
• Sen, Unal
• Kim, Choongik
• Usta, Hakan

Titel

Ultralow bandgap molecular semiconductors for ambient-stable and solution-processable ambipolar organic field-effect transistors and inverters

Ist Teil von

• Journal of materials chemistry. C, Materials for optical and electronic devices, 2017, Vol.5 (9), p.2368-2379

Erscheinungsjahr

2017

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• The design and development of novel ambipolar semiconductors is very crucial to advance various optoelectronic technologies including organic complementary (CMOS) integrated circuits. Although numerous high-performance ambipolar polymers have been realized to date, small molecules have been unable to provide high ambipolar performance in combination with ambient-stability and solution-processibility. In this study, by implementing highly π-electron deficient, ladder-type IFDK/IFDM acceptor cores with bithiophene donor units in D–A–D π-architectures, two novel small molecules, 2OD-TTIFDK and 2OD-TTIFDM , were designed, synthesized and characterized in order to achieve ultralow band-gap (1.21–1.65 eV) semiconductors with sufficiently balanced molecular energetics for ambipolarity. The HOMO/LUMO energies of the new semiconductors are found to be −5.47/−3.61 and −5.49/−4.23 eV, respectively. Bottom-gate/top-contact OFETs fabricated via solution-shearing of 2OD-TTIFDM yield perfectly ambient stable ambipolar devices with reasonably balanced electron and hole mobilities of 0.13 cm 2 V −1 s −1 and 0.01 cm 2 V −1 s −1 , respectively with I on / I off ratios of ∼10 3 –10 4 , and 2OD-TTIFDK -based OFETs exhibit ambipolarity under vacuum with highly balanced ( μ e / μ h ∼ 2) electron and hole mobilities of 0.02 cm 2 V −1 s −1 and 0.01 cm 2 V −1 s −1 , respectively with I on / I off ratios of ∼10 5 –10 6 . Furthermore, complementary-like inverter circuits were demonstrated with the current ambipolar semiconductors resulting in high voltage gains of up to 80. Our findings clearly indicate that ambient-stability of ambipolar semiconductors is a function of molecular orbital energetics without being directly related to a bulk π-backbone structure. To the best of our knowledge, considering the processing, charge-transport and inverter characteristics, the current semiconductors stand out among the best performing ambipolar small molecules in the OFET and CMOS-like circuit literature. Our results provide an efficient approach in designing ultralow band-gap ambipolar small molecules with good solution-processibility and ambient-stability for various optoelectronic technologies, including CMOS-like integrated circuits.