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Journal ArticleDOI

Photo-Response of Low Voltage Flexible TIPS-Pentacene Organic Field-Effect Transistors

15 Jun 2017-IEEE Sensors Journal (IEEE)-Vol. 17, Iss: 12, pp 3689-3697
TL;DR: In this paper, photo-response of solution processed flexible TIPS-pentacene organic field effect transistors is evaluated under illumination with visible light of red, green, and blue colors having minimum wavelengths of 620, 520, and 460 nm.
Abstract: Photo-response of solution processed flexible TIPS-pentacene organic field-effect transistors is evaluated under illumination with visible light of red, green, and blue colors having minimum wavelengths of 620, 520, and 460 nm. For −10 V operation, pristine photo-OFETs exhibited average field-effect mobility of 0.11 cm $^{2}\text{V}^{-1}\text{s}^{-1}$ , near zero threshold voltage, and current ON–OFF ratio of ~105. These photo-OFETs exhibited prevalent photovoltaic characteristics with shift in the threshold voltage upon illumination, which was found to increase with rising intensity, illumination time, and gate bias during illumination. For low-voltage operation at −5 V, maximum current modulation of $4\times 10^{4}$ and 102, and photo-responsivity of 17 mA/W and 35 mA/W, respectively, were achieved for blue (intensity of 1.7 mW/cm2) and green (intensity of 0.4 mW/cm2) light illuminations. However, these photo-OFETs did not show significant response to red light. A fast dynamic response to periodic pulses of illumination was also observed. For a gate bias of +10 V and illumination time of 500 s, maximum current modulation of 105 was achieved for blue light illumination.
Citations
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Journal ArticleDOI
TL;DR: In this paper , the authors used gelatin, a natural biopolymer gate dielectric, and TIPS-pentacene as an organic semiconductor to achieve a low leakage current and low-voltage operation.
Abstract: Organic field-effect transistors (OFETs) have opened up new possibilities as key elements for skinlike intelligent systems, due to the capability of possessing multiple functionalities. Here, multifunctional OFET devices based on gelatin, a natural biopolymer gate dielectric, and TIPS-pentacene as an organic semiconductor are extensively explored. Gelatin is combined with a thin high-k HfO2 dielectric layer deposited by atomic layer deposition (ALD) to achieve a low leakage current and low-voltage operation. The natural biopolymer offers a better semiconductor:dielectric interface, leading to better charge conduction in the devices, along with an enhancement of sensing capabilities giving additional functionality. These fabricated flexible OFET devices exhibit excellent electrical characteristics with a high field-effect mobility reaching over 2 cm2/(V s) (extracted with Ci at 1 kHz), a low subthreshold swing (SS) of ∼200 mV/dec, and a high current on–off (Ion/Ioff) ratio at a low operating voltage of −5 V with excellent electrical and mechanical stability. Moreover, circuit and multiparameter sensing capabilities for visible and UV light, as well as for humidity and breath rate, have been successfully demonstrated for these devices. Our results indicate that these multifunctional OFET devices can open up a plethora of opportunities for practical applications such as real-time health and environmental monitoring.

10 citations

Journal ArticleDOI
TL;DR: In this article, the effect of ultra-violet (UV) irradiation on the electrical characteristics of solution processed flexible TIPS-pentacene organic field effect transistors (OFETs) has been investigated.

9 citations

Journal ArticleDOI
TL;DR: In this article, a combination of a thin layer of copper (II) phthalocyanine (CuPc) and TIPS-pentacene crystal was used to enhance the photo-sensing spectrum of photo-sensitive organic field effect transistors (photo-OFETs).

9 citations

Journal ArticleDOI
14 May 2021-Polymer
TL;DR: In this paper, the crucial role of molecular weight of the polymer dielectric in regulating the electrical performance and photo-response of TIPS-pentacene OFETs has been explored using poly(vinyl alcohol) (PVA) as the polymer layer.

4 citations

References
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Journal ArticleDOI
TL;DR: In this article, a vertically stacked complementary inverter with a solution-processed [6,6]-phenyl c 61 butyric acid methyl ester (PCBM) n -channel thin-film transistor (TFT) fabricated on top of a 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-pentacene) and poly(triarylamine) (PTAA) blend p -channel TFT was presented.

39 citations

Journal ArticleDOI
TL;DR: In this paper, a solution-processed diF-TESADT phototransistor was used for large-area and low-cost optical sensors and memory applications, and it was found that the V TH shift can be further enlarged by an additional gate bias, achieving very high light responsivity >10 3 ǫA/W at 0.17 mW/cm 2 and I PH /I DARK ratio higher than 10 6.

38 citations


"Photo-Response of Low Voltage Flexi..." refers background in this paper

  • ...It can be observed from the figure that rates of change in drain current are different on turning the illumination on and off respectively, indicating a different trapping and releasing behavior of charge carriers [52]....

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  • ...rich PVP surface, whereas at later stages, rate of rise in the drain current slows down due to coulombic repulsion between trapped and incoming electrons [52]....

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  • ...This improvement indicates that photoresponse of a photo-FET can be enhanced by application of a suitable gate bias during illumination [52]....

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Journal ArticleDOI
TL;DR: In this paper, a study performed on organic thin film transistors based on poly(3-hexylthiophene) with molecular weights ranging from 20 to 80 kDa as active material was performed.
Abstract: We present a study performed on organic thin film transistors based on poly(3-hexylthiophene) with molecular weights ranging from 20 to 80 kDa as active material. Besides having a strong influence on the absolute value of the mobility, we show that the molecular weight also drastically affects the mobility functional dependence on the gate voltage and on the longitudinal electric field. While the medium range of molecular weight (37–53 kDa) yields a high (about 10−2 cm2/V s) and practically constant mobility, the low and high ranges yield a lower mobility, which in addition shows a strong dependence on both the charge density and the electric field. By means of a detailed analysis of experimental transfer characteristics of transistors, this behavior is traced back to the broadness of the density of states, which turns out to be higher for low mobility polymers. Finally, consequences on transistor modeling due to the simultaneous dependence of the mobility on charge density and electric field are discussed.

34 citations


"Photo-Response of Low Voltage Flexi..." refers background in this paper

  • ...the density of excess charge carriers [44], [45]....

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Journal ArticleDOI
TL;DR: In this paper, stable organic photodetectors with all-small molecular bulk heterojunction (BHJ) sensing layers prepared using solutions of electron-donating and electron-accepting small molecules were reported.
Abstract: We report stable organic photodetectors with all-small molecular bulk heterojunction (BHJ) sensing layers prepared using solutions of electron-donating and electron-accepting small molecules. As an electron-donating molecule, 2,5-bis(2-ethylhexyl)-3,6-bis(4′-methyl-[2,2′-bithiophen]-5-yl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione (EHTPPD-MT) was synthesized via a Stille coupling reaction, whereas [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) was used as an electron-accepting component. The devices with the EHTPPD-MT:PC61BM BHJ layer could detect photons at a wavelength of 400–800 nm and exhibited a stable photoresponse under on/off modulation of near UV (405 nm) and visible (532 nm and 650 nm) light even at bias voltage conditions. The corrected responsivity reached ∼175 mA W−1 for the near UV detection at −1 V. An extremely durable photoresponse was measured for the present devices (including flexible devices) under illumination with high intensity green light (133.4 mW cm−2 at 532 nm) which is much stronger than standard sun light (100 mW cm−2, white). The excellent stability has been attributed to the tiny EHTPPD-MT crystals, which are formed in the EHTPPD-MT:PC61BM layers during the coating processes.

29 citations


"Photo-Response of Low Voltage Flexi..." refers background in this paper

  • ...However, some of the donor-acceptor systems show high performance and are extensively explored which include P3HT/ PCBM [23]–[25], PPV derivatives/PCBM [26], [27], F8BT/PDI [28], PTT/PCBM [29], PCPDTBT/ PCBM [30], PEDOT:PSS/PCDTBT:PCBM [31], EHTPPDMT/PCBM [32], and PEDOT:PSS/PCBM:BCP [33]....

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Journal ArticleDOI
TL;DR: In this paper, the effects of UV and white light illuminations on the electrical and photosensing properties of the 6,13-bis (triisopropylsilylethynyl)pentacene thin film transistor were investigated.
Abstract: The effects of UV and white light illuminations on the electrical and photosensing properties of the 6,13-bis(triisopropylsilylethynyl)pentacene thin film transistor were investigated. The photosensitivity (Iph/Idark) values of the transistor in the OFF state were found to be 1.156 and 2.12 under UV 365 nm (for Vg = −10 V) and white light illuminations (for Vg = −10 V and P = 100 mW/cm2), respectively. The threshold voltage value of the TIPS-pentacene transistor was shifted from a smaller (0.215 V) value to higher (1.095 V) value with UV illumination, while it was shifted from a negative value (−1.29 V) to positive value (0.525 V) with white light illumination. The mobility μ value (3.412 × 10−2 cm2/Vs) of the TIPS-pentacene transistor under dark is lower than that of the values under UV and white light illuminations. The sub-threshold swing value under dark is higher than that of under UV and white light illuminations. The interface trap density of the TIPS-pentacene transistor is decreased with increasing illumination. The lowest Dit value (0.941 × 1013 eV−1 cm−2) of the TIPS-pentacene transistor causes the highest mobility (6.322 × 10−2 cm2/Vs). The photoresponsivity R values of the TIPS-pentacene transistor vary from 11.58 mA/W to 53.48 mA/W.

28 citations