Poly(thieno[3,4-<i>b</i>]thiophene):  A p- and n-Dopable Polythiophene Exhibiting High Optical Transparency in the Semiconducting State

Sotzing, Gregory A.; Lee, Kyung-Hoon

doi:10.1021/ma020367j

Cited by 98 publications

(84 citation statements)

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“…[17,18] Polythieno[3,4-b]thiophene (PTT) is one kind of LBG polymers in which the fused thiophene moieties can stabilize the quinoid structure of the backbone, thereby reducing the band gap of the conjugated system. [19,20] Several PTTs without side chains have been reported previously, but the poor solubility makes them difficult to process and limits their use in electro-optical and electronic devices. [21][22][23] Synthesis of alkyl chains substituted thieno [3,4-b]thiophenes monomers have been reported and the resulting polymers exhibit better solubility, but poor oxidative stability.…”

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confidence: 99%

Plastic Near‐Infrared Photodetectors Utilizing Low Band Gap Polymer

et al. 2007

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Organic photodetectors (PDs) have been the subject of extensive research in the past decade due to several inherent advantages: large-area detection, wide selection of materials, and low-cost fabrication on flexible substrates. High external quantum efficiency (EQE) [1,2] , full-color [3,4] , fast-response [5,6] , and position-sensitive [7] PDs have been reported in the past.However, there are few reports on organic near-infrared photodetectors (NIR-PDs) in spite of their tremendous potential in industrial and scientific applications, such as remote control, chemical/biological sensing, optical communication, and spectroscopic and medical instruments.[8] S. Meskers and co-workers reported an infrared PD in which doped poly(2, 4-ethylenedioxythiophene)/poly(styrene sulfonic acid) (PEDOT/PSS) was used as the active material.[9] More recently, G. Konstantatos and coworkers fabricated NIR-PDs by spin-coating colloidal quantum dots from solution onto gold interdigitated electrodes.[10] The device showed a large photoconductive gain and high detectivity at 1.3 lm. However, 3-dB bandwidth was only about 18 Hz and the working voltage was as high as 40 V. These characteristics strongly restrict their applications in the fields of imaging and communication where high-speed and low-power PDs are desired. Thus, there is a strong need for the development of fast response and low working voltage NIR-PDs while simultaneously maintaining the benefit of low-cost solution process.Here we report an organic near-infrared photodetector using a new low band gap polymer. By utilizing an ester group modified polythieno[3,4-b]thiophene, we have successfully lowered the highest occupied molecular orbital (HOMO) energy level of the low band gap (LBG) polymer, so that it can match the energy level of (6,6)-phenyl C 61 -butyric acid methyl ester (PCBM), and has good solubility and easy processing ability.In this communication, we report a device which has a donoracceptor type energy structure whose operation shows excellent NIR detection capability. Reports on LBG polymers for solar energy conversion have emerged recently. [11][12][13][14][15][16] The preparation of LBG, high mobility, solution-processable polymers is not trivial and requires judicious design.[16] Among several band gap tuning strategies for conjugated polymers, polymerization of fused heterocyclic rings has been known to yield polymers with very low band gaps. [17,18] Polythieno[3,4-b]thiophene (PTT) is one kind of LBG polymers in which the fused thiophene moieties can stabilize the quinoid structure of the backbone, thereby reducing the band gap of the conjugated system. [19,20] Several PTTs without side chains have been reported previously, but the poor solubility makes them difficult to process and limits their use in electro-optical and electronic devices. [21][22][23] Synthesis of alkyl chains substituted thieno [3,4-b]thiophenes monomers have been reported and the resulting polymers exhibit better solubility, but poor oxidative stability. [19] It was found that the HO...

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Plastic Near‐Infrared Photodetectors Utilizing Low Band Gap Polymer

et al. 2007

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“…Thieno [3,4-b]thiophene (T34bT): T34bT was synthesized in accordance to literature procedure from 3,4-dibromothiophene as a colorless liquid with 42 % overall yield [16,19]. Boiling point (b.p.)…”

Section: Methodsmentioning

confidence: 99%

“…Herein, we report an example wherein ring sulfonation of insoluble poly(thieno [3,4-b]thiophene) (PT34bT) [16] was carried out to produce a low-bandgap, water-processable SPoT. Furthermore, we have demonstrated the ability to control the sulfonation level and thereby alter spectral properties.…”

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confidence: 99%

Ring‐Sulfonated Poly(thienothiophene)

et al. 2005

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with different pore sizes: a polystyrene±block±poly(ethylene oxide) (SE1010) provided by Goldschmidt for the material M5 (made as described previously [7]), a hydrogenated polybutadiene±block±poly (ethyleneoxide) (PBPEO20) for the material M13 (made as described previously [9]), and an aqueous polystyrene latex dispersion (LAT) with a solid content of 9 % for the material M60 (made in analogy to a previous method [10]).The dried and aged silica gels were calcined in a muffle-type furnace at 550 C for 6 h. The resultant mesoporous matrices where characterized by TEM and nitrogen sorption measurements (BET). Table 2 summarizes the composition of the synthesized materials.Synthesis of the g-C 3 N 4 Nanospheres: Cyanamide (CH 2 N 2 ) was used as a molecular precursor because its low melting point (47 C) allows convenient filling of the silica matrices by soaking at slightly elevated temperatures. The monolithic silica material was placed in liquid cyanamide at 70 C and kept there for 30 min. The monoliths were then taken out, dried in air, and the surface-adsorbed cyanamide molecules were washed away by dipping in ethanol.When the hybrid material was dry again, the reaction was carried out by heating the monolith under flowing N 2 up to 550 C with a heating ramp of 5 K min ±1 . Three hours of isothermal treatment completed the reaction.The monoliths were then crushed into a fine powder with a ball mill and treated with an excess of hydrofluoric acid (5 %) twice for 24 h to free the C 3 N 4 spheres from the silica matrix. The centrifuged C 3 N 4 powder was separated from the HF solution and washed with distilled water. Note that special precautionary measures are required when working with HF.The purity of the samples and the silica leftovers were determined by thermogravimetric analysis (TGA). The samples were temperature-stable up to 550 C and contained 2±5 % silica residue.Characterization of the Materials: TEM images were taken with a Zeiss EM 912X at an acceleration voltage of 120 kV. SEM was performed on a Zeiss DSM 940 A. Tapping-mode AFM images were recorded with a multimode atomic force microscope from Veeco Instruments using Olympus microcantilevers (resonance frequency: 300 kHz; force constant: 42 N m ±1 ). The samples were redispersed in water using ultrasonication and one droplet was spin-coated onto a freshly prepared mica substrate. X-ray data were recorded with a Siemens D8 diffractometer equipped with a Sol X, SI solid-state detector, using Cu Ka radiation in a symmetric reflection setup. Sorption measurements (BET) were obtained with a Micromeritics Tristar 3000. Elemental analyses (C, H, N, S) were performed on a Vario EL Elementar (Elementar Analyzen-systeme, Hanau, Germany). The IR spectra were collected with a BIORAD FTS 6000 FTIR spectrometer, equipped with an attenuated total reflection (ATR) setup. Steady-state fluorescence spectra were recorded on a Perkin±Elmer LS50B luminescence spectrometer. TGA was performed on a Netzsch TG 209. DSC was performed on a Netzsch DSC 204.

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“…By incorporating alkoxyl BDT with thieno [3,4-b]thiophene, P37 (P37-50 structure in Chart 4) was developed, with an E g 1.62eV (Liang et al, 2009a). Thieno [3,4-b]thiophene repeating units contributed to the stability of the quinoidal structure of the backbone narrowing the energy gap of resulting polymer (Sotzing & Lee, 2002). Thieno [3,4-b]thiophene with ester substituents in P37 contributed both good solubility and oxidative stability.…”

Section: Thiophene-based Conjugated Polymersmentioning

confidence: 99%