591771-94-7Relevant articles and documents
Influence of the terminal donor on the performance of 4,8-dialkoxybenzo[1,2-b:4,5′]dithiophene based small molecules for efficient solution-processed organic solar cells
Bagde, Sushil S.,Park, Hanok,Lee, Song-Mi,Lee, Soo-Hyoung
, p. 2063 - 2070 (2016/03/19)
Two π-conjugated small molecules, BDT(TTBT)2 and BDT(PTBT)2, based on benzodithiophene (BDT) and benzothiadiazole (BT) substituted with different terminal groups such as hexyl-bithiophene and hexylphenyl-thiophene are investigated for use in solution-processed organic solar cells (OSCs). Investigations into the molecules reveal that variation of the terminal groups not only influences the optical and electronic properties, but also affects the crystallization and morphology of the small molecules. The BDT(TTBT)2 device showed a power conversion efficiency (PCE) of 1.73% as a consequence of deep HOMO (Voc = 0.81 V), improved charge delocalization, and strong light absorption (Jsc = 4.75 mA cm-2) when mild annealing was used as a result of improved texture in morphology, while the BDT(PTBT)2 device rather showed a moderate PCE of 1.22% with a Jsc of 2.88 mA cm-2, a Voc of 0.81 V, and a FF of 0.52.
Preparation and acid-responsive photophysical properties of T-shaped π-conjugated molecules containing a benzimidazole junction
Inouchi, Toshifumi,Nakashima, Takuya,Toba, Masaya,Kawai, Tsuyoshi
experimental part, p. 3020 - 3027 (2012/07/03)
T-shaped π-conjugated molecules with an N-methyl-benzimidazole junction have been synthesized and their acid-responsive photophysical properties owing to the change in the π-conjugation system are discussed. T-shaped π-conjugated molecules consist of two orthogonal π-conjugated systems including a phenyl thiophene extended from the 2-position and alkyl phenylenes connected through various π-spacers from the 4,7-positions of the N-methyl-benzimidazole junction. The π-spacers, such as thiophene, ethyne, and ethane, have an effect on the acid response of photophysical properties in terms of changes in conformation, excited-state energy and charge-transfer (CT) characteristics. In particular, the π-conjugated molecule with ethynyl spacers exhibited a marked redshift in the fluorescence spectrum with a large Stokes shift upon the addition of acid, whereas the other molecules showed substantial quenching. The redshift in emission was studied in detail by temperature-dependent fluorescence measurements, which indicated the transition to a CT state over the finite activation energy at the excited state. The change in the frontier molecular orbitals upon acid addition was further discussed by means of DFT calculations.
Easily processable phenylene-thiophene-based organic field-effect transistors and solution-fabricated nonvolatile transistor memory elements
Mushrush, Melissa,Facchetti, Antonio,Lefenfeld, Michael,Katz, Howard E.,Marks, Tobin J.
, p. 9414 - 9423 (2007/10/03)
The synthesis of a new series of mixed phenylene - thiophene oligomers is reported; 2,5-bis(4-n-hexylphenyl)thiophene (dH-PTP, 1), 5,5′-bis(4-n- hexylphenyl)-2,2′-bithiophene (dH-PTTP, 2), 5,5″-bis-(4-n-hexylphenyl)-2,2′:5′,2″-terthiophene (dH-PT3P, 3), 5,5?-bis(4-n-hexylphenyl)-2,2′:5′, 2″:5′,2?-quater-thiophene (dH-PT4P, 4), 1,4-bis[5-(4-n-hexylphenyl)-2-thienyl]benzene (dH-PTPTP, 5), and 2,5-bis[4(4′-n-hexylphenyl)phenyl]thiophene (dH-PPTPP, 6) were characterized by 1H NMR, elemental analysis, UV-visible spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. Vacuum-evaporated and solution-cast films were characterized by X-ray diffraction and scanning electron microscopy. All compounds display high p-type carrier mobilities as evaporated (up to 0.09 cm2/Vs) and as solution-cast (up to 0.03 cm2/Vs) films on both Si/SiO2 and ITO/GR (glass resin) substrates. The straightforwardly synthesized dH-PTTP (2) displays an unprecedented combination of mobility, on/off ratio, stability, and processability. Both dH-PTTP (2) and dH-PPTPP (6) display a reversible, tunable, and stable memory effect even as solution-cast devices, with turn-on characteristics shifting from accumulation mode to zero or depletion mode after a writing voltage Vw is applied. The charge storage is distributed over the gate dielectric structure and is concentrated near the dielectric-semiconductor interface, as evidenced by the response of floating gate configuration devices. Simple nonvolatile elements have been fabricated by solution-only techniques on ITO substrates using spin-coated glass resin, solution-cast oligomeric semiconductors, and painted graphite paste electrodes.
