Versatile α,ω‐Disubstituted Tetrathienoacene Semiconductors for High Performance Organic Thin‐Film Transistors

Youn, Jangdae; Huang, Peng; Huang, Yu; Chen, Ming Chou; Lin, Yu Jou; Huang, Hui; Ortiz, Rocío Ponce; Stern, Charlotte L.; Chung, Ming Che; Feng, Chieh Yuan; Chen, Liang Hsiang; Facchetti, Antonio; Marks, Tobin J.

doi:10.1002/adfm.201101053

Cited by 83 publications

(50 citation statements)

References 61 publications

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“…[ 27,28 ] Recently, many research groups have reported that the presence of fused thiophene units in π -conjugated oligomers is an effective means of invoking strong intermolecular interactions and improving environmental stability. [29][30][31][32][33] …”

Section: Resultsmentioning

confidence: 99%

Solution‐Processed Small‐Molecule Bulk Heterojunction Ambipolar Transistors

Cheng

Huang

Ramesh

et al. 2013

Adv Funct Materials

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Organic thin-fi lm transistors (OTFTs) have attracted much attention due to their potential applications in high-value, low-cost electronic devices, including displays, sensors, radio-frequency identifi cation components, and e-papers. [1][2][3] Current research in OTFT materials is focused primarily on the design and synthesis of conjugated organic compounds and polymers that are environmentally stable and capable of carrier transport. Several conjugated organic compounds and polymers have been developed with promising carrier mobilities, comparable to that of amorphous silicon. [4][5][6] To exploit such materials in a wider range of practical applications, high-performance inverters, which are the building blocks of integrated circuits (ICs), must be developed. Complementary metal-oxide semiconductor (CMOS) technology is desirable for the preparation of ICs because it provides straightforward circuit design, good noise margins, low power consumption, and robust operation. Organic CMOS technology requires the use of p-and n-type transistors on the same substrate; however, the separate vacuum-deposition of p-and n-type semiconductors increases the complexity of the circuit fabrication process. [ 7,8 ] To overcome this problem, researchers have explored several strategies, including: i) ambipolar OTFTs featuring symmetric or asymmetric source and drain electrodes for single organic semiconductors; [9][10][11][12] ii) bilayer structures consisting of hole-and electron-transporting organic compounds; [13][14][15][16] and iii) blending two organic semiconductors with different polarities to eliminate the need to pattern the p-and n-channel semiconductors in separation regions. [17][18][19][20] In a single-material confi guration, the effi cient injection of both holes and electrons is the key factor affecting the performance of ambipolar OTFTs. Improved carrier mobility can be achieved by lowering the barrier between the energy levels of the metal and those of the highest occupied molecular orbital (HOMO) of the organic semiconductor for hole transport, and of the lowest unoccupied molecular orbital (LUMO) for electron transport. Most organic semiconductors have a wide band gap (ca. 2-3 eV), resulting in a mismatch between the work function of the electrode and the organic semiconductor for at least one of the carriers. Although devices featuring asymmetric electrodes could circumvent this drawback, the preparation of such a device demands an additional deposition step. Therefore, several research groups have investigated the use of a bilayer structure, with carrier mobility of electrons and holes reaching as Shiau-Shin Cheng , Peng-Yi Huang , Mohan Ramesh , Hsiu-Chieh Chang , Li-Ming Chen , Chia-Ming Yeh , Chun-Lin Fung , Meng-Chyi Wu , Chung-Chi Liu , Choongik Kim ,* Hong-Cheu Lin , Ming-Chou Chen ,* and Chih-Wei Solution-Processed Small-Molecule Bulk Heterojunction Ambipolar Transistors

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Section: Resultsmentioning

confidence: 99%

Solution‐Processed Small‐Molecule Bulk Heterojunction Ambipolar Transistors

Cheng

Huang

Ramesh

et al. 2013

Adv Funct Materials

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“…This hole fi lling of trap states can sometimes lead to higher fi eld-effect mobilities. [ 29 ] data ( Figure 7 ), thereby suggesting a plausible reason for the reduced carrier mobility observed for BBTDT versus P-BTDT , despite the fact that the larger BBTDT π -core relative to the other BTDT molecules is expected, all other things being equal, to increase the electronic interaction between π orbitals of adjacent molecules, [ 22 ] and to decrease the Marcus reorganization energy. [ 27 , 28 ] The case of PF-BTDT is unique in that the thin fi lm structure does not correlate with the bulk single crystal structure.…”

Section: Organic Thin-film Transistor (Otft) Characterizationmentioning

confidence: 97%

“…However, PF-BTDT exhibits a 5% weight loss temperature ≈ 247 ° C, lower than that of P-BTDT , indicating higher volatility due to the fl uorocarbon substitution. [ 22 ] The optical absorption spectra of Bp-BTDT , Np-BTDT , and BBTDT in o -C 6 H 4 Cl 2 solution (Supporting Information Figure S1) are slightly red-shifted ( λ max > 369 nm), relative to that of the P-BTDT ( λ max ≈ 358 nm). In contrast, the absorption spectrum of PF-BTDT is slightly blue-shifted relative to P-BTDT .…”

Section: Thermal Optical and Electrochemical Properties Of Btdt Dermentioning

confidence: 98%

Fused Thiophene Semiconductors: Crystal Structure–Film Microstructure Transistor Performance Correlations

Youn

Kewalramani

Emery

et al. 2013

Adv Funct Materials

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The molecular packing motifs within crystalline domains should be a key determinant of charge transport in thin-fi lm transistors (TFTs) based on small organic molecules. Despite this implied importance, detailed information about molecular organization in polycrystalline thin fi lms is not available for the vast majority of molecular organic semiconductors. Considering the potential of fused thiophenes as environmentally stable, highperformance semiconductors, it is therefore of interest to investigate their thin fi lm microstructures in relation to the single crystal molecular packing and OTFT performance. have been scrutinized, such assumptions have been proven to sometimes be inaccurate, and it is now known that molecular packing in thin fi lms may differ signifi cantly from that in the bulk crystal structures, especially near the dielectric interface. For example, in thin fi lm form, both tetraceno[2,3-b]thiophene [ 17 ] and pentacene [ 16 ] exhibit a local molecular packing distinctly different from that in the bulk crystal. These observations highlight the necessity of obtaining microstructural details for thin organic fi lms.In this contribution, the molecular packing motifs of fi ve newly synthesized BTDT [ 9 ] derivatives ( Scheme 2 ), are studied both in bulk single crystals and in thin fi lms by single crystal diffraction and grazing incidence wide angle X-ray scattering (GIWAXS). We fi rst introduce the new BTDT molecules and describe their thermal, optical, and electrochemical properties. We then compare the bulk and thin fi lm structures by analyzing single-crystal X-ray diffraction and GIWAXS data. Lastly, the effect of thin fi lm microstructure on TFT performance is discussed. The results indicate that these BTDT derivatives have different molecular packing in thin fi lms versus the bulk crystals. In the case of P-BTDT , Bp-BTDT , Np-BTDT , and BBTDT , it will be seen that two types of lattices coexist, and that these are slightly strained compared to their bulk crystal forms. In contrast, for PF-BTDT fi lms, a single lattice is observed, however, this lattice has no apparent correspondence to the bulk crystal form. For P-BTDT , which yields the best performing TFTs of the series, the dominance of the more strained lattice relative to the bulk-like lattice may explain the excellent charge transport properties. On the other hand, poor crystallinity and poor surface coverage at the substrate interface explains the poor device performance of PF-BTDT fi lms. Results SynthesisDetails of the various BTDT syntheses can be found in the Supporting Information or previous literature. [ 9 ] Briefl y, the derivatives [ 2 , 9-14 ] offer a potential solution to this challenge, owing to their combination of suffi ciently high-lying excited states and high ionization potentials to suppress photo-oxidation, [ 11 ] and bulk single crystal packing motifs which are very similar to that of pentacene. Among organic semiconductor materials for p-channel devices, several fused thiophene derivatives with increased numb...

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“…Despite the excellent performance of fused-thiophenes in OTFTs [61][62][63][64][65][66], fused-thiophene-based OPV and DSSC studies are still in their infancy. It is well known that there are a number of factors determining the efficiency of the photovoltaic cells, and that the multiparameter problem remains to be solved.…”

Section: Discussionmentioning

confidence: 99%

Fused-Thiophene Based Materials for Organic Photovoltaics and Dye-Sensitized Solar Cells

et al. 2014

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Organic photovoltaics (OPVs) and dye-sensitized solar cells (DSSCs) have drawn great interest from both academics and industry, due to the possibility of low-cost conversion of photovoltaic energy at reasonable efficiencies. This review focuses on recent progress in molecular engineering and technological aspects of fused-thiophene-based organic dye molecules for applications in solar cells. Particular attention has been paid to the design principles and stability of these dye molecules, as well as on the effects of various electrolyte systems for DSSCs. Importantly, it has been found that incorporation of a fused-thiophene unit into the sensitizer has several advantages, such as red-shift of the intramolecular charge transfer band, tuning of the frontier molecular energy level, and improvements in both photovoltaic performance and stability. This work also examines the correlation between the physical properties and placement of fused-thiophene in the molecular structure with regard to their performance in OPVs and DSSCs. OPEN ACCESSPolymers 2014, 6 2646

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Versatile α,ω‐Disubstituted Tetrathienoacene Semiconductors for High Performance Organic Thin‐Film Transistors

Cited by 83 publications

References 61 publications

Solution‐Processed Small‐Molecule Bulk Heterojunction Ambipolar Transistors

Solution‐Processed Small‐Molecule Bulk Heterojunction Ambipolar Transistors

Fused Thiophene Semiconductors: Crystal Structure–Film Microstructure Transistor Performance Correlations

Fused-Thiophene Based Materials for Organic Photovoltaics and Dye-Sensitized Solar Cells

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