Microdisk and Microring Lasers of Thiophene–Phenylene Co‐Oligomers Embedded in Si/SiO<sub>2</sub> Substrates

Sasaki, Fumio; Kobayashi, Shunsuke; Haraichi, Satoshi; Fujiwara, Seiji; Bando, Kiyoshi; Masumoto, Yasuaki; Hotta, Shu

doi:10.1002/adma.200701008

Cited by 40 publications

(39 citation statements)

References 20 publications

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“…[3] Very advantageous in this field is the possibility of the tuning of the molecular architecture pursuing optimal electronic response and, consequently, oligomers of thiophene have been co-oligomerized or combined in the same conjugational path with other conjugating groups such as acetylene, benzene, pyrrol and vinylene. [4] Another strategy is the substitution of the terminal a-positions with electro-active groups trying to facilitate electronic communication and charge polarization. [5] Ferrocene (i.e., Fc) is well known as Abstract: New oligothiophene-vinylene compounds have been synthesized in order to study the role of the conjugated chain in two different cases: 1) when push-pull action operates between an electron-donor and an electron-acceptor group at the ends of the thiophene-vinylene conjugated chain, and 2) when mixed-valence action is induced by single oxidation of the same chain functionalized at both terminal positions with ferrocene groups leading to competition between the donor groups.…”

Section: Introductionmentioning

confidence: 99%

Ferrocenyl‐Ended Thieno–Vinylene Oligomers: Donor–Acceptor Polarization and Mixed‐Valence Properties with Emphasis on the Raman Mapping of Localized‐to‐Delocalized Transitions

Casado

González

Delgado

et al. 2009

Chemistry A European J

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What's your role? New oligothiophene-vinylene compounds have been synthesized to study the role of the conjugated chain in two different cases (see scheme; MV=mixed valence). The electronic and molecular structures were analyzed by means of electronic, X-ray photoelectron, and Raman spectroscopy, together with thermo spectroscopy, electrochemistry, and DFT calculations.New oligothiophene-vinylene compounds have been synthesized in order to study the role of the conjugated chain in two different cases: 1) when push-pull action operates between an electron-donor and an electron-acceptor group at the ends of the thiophene-vinylene conjugated chain, and 2) when mixed-valence action is induced by single oxidation of the same chain functionalized at both terminal positions with ferrocene groups leading to competition between the donor groups. The electronic and molecular structures are analyzed by means of electronic, X-ray photoelectron and Raman spectroscopies, together with thermospectroscopy, electrochemistry and density functional theory calculations. The cyclic voltammetry processes have been followed by spectrochemistry. It is shown that the radical cation of the diferrocenyl derivative is a class III mixed-valence system (i.e., fully delocalized) according to its Raman spectrum. Moreover, by Raman thermo-spectroscopy the thermal transition of this radical cation from a delocalized (class III, room temperature) to a localized (class II, -160 degrees C) state is scanned. In all cases the Raman study is paralleled by an electronic absorption spectroscopic analysis. Structure-property relationships are proposed for molecules of two important fields of very active research as that of the non-linear optics (i.e., organic optoelectronic) and that of the mixed-valence systems (i.e., charge-transfer processes).

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Section: Introductionmentioning

confidence: 99%

Ferrocenyl‐Ended Thieno–Vinylene Oligomers: Donor–Acceptor Polarization and Mixed‐Valence Properties with Emphasis on the Raman Mapping of Localized‐to‐Delocalized Transitions

Casado

González

Delgado

et al. 2009

Chemistry A European J

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“…Amongst organic semiconducting materials, thiophene/ phenylene co-oligomers are considered promising because of their unique optoelectronic properties. [5,8,12,13] Hence we have chosen for the present study one of the co-oligomers, 2,5-bis(4-biphenylyl)thiophene (BP1T) [14] (see structural formula in Fig. 1a).…”

mentioning

confidence: 99%

Organic Light‐Emitting Field‐Effect Transistors Operated by Alternating‐Current Gate Voltages

et al. 2008

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Organic light-emitting field-effect transistors (OLEFETs) are currently under intensive study owing to their multifunctionality, including current modulation and light emission.[1] This multifunctionality is associated with their potential applicability to display technology. Organic light-emitting diodes (OLEDs) constitute another class of organic lightemitting devices, which require transistors controlling their luminance. In OLEFETs, on the other hand, the luminance can be modulated by changing only gate voltages, without any additional devices. Thus, display panels using OLEFETs have the great advantage of largely reducing both the number of devices and the circuit complexity. The device performance of OLEFETs is based upon the simultaneous carrier injection of both holes and electrons into an organic semiconductor layer, and their subsequent recombination. So far, OLEFETs [2][3][4][5][6][7][8][9][10][11] have been operated by applying direct-current (DC) voltages to the gate contact and between the source and drain electrodes. Within this framework several attempts were made to promote the injection and recombination of the carriers. Examples include the use of heterogeneous metal electrodes [6,8,10,11] and composite organic semiconductors.[3] These attempts, however, made the device structure complicated, and the improvement was yet insufficient. Thus, the difficulty in injecting electrons and holes simultaneously into the organic layer imposed serious restrictions on the structure and steady operation of such devices, and hence hampered the versatility of OLEFETs. This has urged us to renovate the device operation method. In this communication, we propose a novel method of operation for the devices, characterized by the application of alternating-current (AC) voltages to the gate electrode. This prompts the carrier injection from both the drain and source electrodes into an organic layer. Moreover, stable metals such as gold and platinum can be used in those electrodes, to inject both holes and electrons. The organic layer can be constructed in any desired form, e.g., as a thin film or a crystal. As a result, we have been successful in effectively producing strong emissions without altering the device constitution. The devices are operated under AC gate frequencies of 2-20,000 Hz of appropriate gate voltage amplitudes; stronger emissions take place with increasing gate frequencies. Detailed analysis of the electrical data allows us to distinguish two different regimes in the emission processes. This provides a powerful tool in studying the carrier injection and transport mechanisms in organic semiconducting materials. Amongst organic semiconducting materials, thiophene/ phenylene co-oligomers are considered promising because of their unique optoelectronic properties. [5,8,12,13] Hence we have chosen for the present study one of the co-oligomers, 2,5-bis(4-biphenylyl)thiophene (BP1T) [14] (see structural formula in Fig. 1a). The carrier mobility of the BP1T thin-film device is estimated at $10 À3 cm 2 V À1 ...

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“…1. BP1T was synthesized and purified according to a previously reported method [8][9][10][11]. Each BP1T film was prepared by vapor deposition on a SiO 2 substrate, and was coated with Cytop (CTX809A, Asahi Glass Co. Ltd.), which was diluted by 50%.…”

Section: Methodsmentioning

confidence: 99%

“…We have previously prepared micro-disk and micro-ring lasers with crystalline TPCO films [8], and obtained lasing emissions in whispering gallery mode. Thus, organic crystalline films are suitable for photodevices.…”

Section: Introductionmentioning

confidence: 99%

Large gain for crystalline thin films of thiophene/phenylene co-oligomer by photopumping with femtosecond laser pulses

Mochizuki¹,

Kawaguchi²,

Sasaki³

et al. 2014

Journal of Luminescence

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Microdisk and Microring Lasers of Thiophene–Phenylene Co‐Oligomers Embedded in Si/SiO₂ Substrates

Cited by 40 publications

References 20 publications

Ferrocenyl‐Ended Thieno–Vinylene Oligomers: Donor–Acceptor Polarization and Mixed‐Valence Properties with Emphasis on the Raman Mapping of Localized‐to‐Delocalized Transitions

Ferrocenyl‐Ended Thieno–Vinylene Oligomers: Donor–Acceptor Polarization and Mixed‐Valence Properties with Emphasis on the Raman Mapping of Localized‐to‐Delocalized Transitions

Organic Light‐Emitting Field‐Effect Transistors Operated by Alternating‐Current Gate Voltages

Large gain for crystalline thin films of thiophene/phenylene co-oligomer by photopumping with femtosecond laser pulses

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Microdisk and Microring Lasers of Thiophene–Phenylene Co‐Oligomers Embedded in Si/SiO2 Substrates

Cited by 40 publications

References 20 publications

Ferrocenyl‐Ended Thieno–Vinylene Oligomers: Donor–Acceptor Polarization and Mixed‐Valence Properties with Emphasis on the Raman Mapping of Localized‐to‐Delocalized Transitions

Ferrocenyl‐Ended Thieno–Vinylene Oligomers: Donor–Acceptor Polarization and Mixed‐Valence Properties with Emphasis on the Raman Mapping of Localized‐to‐Delocalized Transitions

Organic Light‐Emitting Field‐Effect Transistors Operated by Alternating‐Current Gate Voltages

Large gain for crystalline thin films of thiophene/phenylene co-oligomer by photopumping with femtosecond laser pulses

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Microdisk and Microring Lasers of Thiophene–Phenylene Co‐Oligomers Embedded in Si/SiO₂ Substrates