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1.
《Organic Electronics》2014,15(1):251-259
In this study we found that the gelation time and crystallinity of P3HT solid films are adjustable when aging and casting from CHCl3/p-xylene mixed solvents. After aging for 36 h in pure p-xylene, CHCl3, or various mixtures of the two as cosolvents, we found that the solid P3HT film gel-cast from 20 vol% CHCl3 had the highest degree of crystallinity of its main chain (ϕm = 0.54), highest melting point of its main chain (Tm = 232.7 °C), fastest gelation time (30 min), largest melting enthalpy of its main chain (ΔHm = 19.81 J g−1), and lowest resistance (RP = 0.76 MΩ); the latter value was three orders and one order of magnitude lower than those of the films cast from pure CHCl3 (ca. 110 MΩ) and pure p-xylene (ca. 4.4 MΩ), respectively. In differential scanning calorimetry scans, we attribute the presence of melting peaks near 75 °C to the solid-to-solid phase transition of the side chain crystallites of P3HT, thereby affecting the aggregation of the P3HT main chain and resulting in the changes in resistance, crystallinity, melting enthalpy, and melting point of the gel-cast P3HT solid films. 相似文献
2.
Agnieszka Iwan Marcin Palewicz Mariusz Ozimek Andrzej Chuchmala Grzegorz Pasciak 《Organic Electronics》2012,13(11):2525-2531
The main goal of the paper was investigation of influence of aluminum electrode preparation via thermal evaporation (TE) and the magnetron sputtering (MS) on power conversion efficiency (PCE) of polymeric solar cells. The photovoltaic properties of such three kinds devices based on poly(3-hexylthiophene-2,5-diyl) (P3HT) as ITO/P3HT/Al, ITO/P3HT:PCBM (1:1, w/w)/Al and ITO/PEDOT:PSS/P3HT:PCBM (1:1, w/w)/Al were investigated. For the constructed devices impedance spectroscopy were analyzed. For devices lack of PEDOT:PSS layer or lack of PCBM, photovoltaic parameters were very low and similar to the parameters obtained for device with Al electrode prepared by magnetron sputtering. The devices comprising PEDOT:PSS with P3HT:PCBM showed the best photovoltaic parameters such as a VOC of 0.60 V, JSC of 4.61 mA/cm2, FF of 0.21, and PCE of 5.7 × 10?1%. 相似文献
3.
We investigated the effect of organic polar solvent on the properties of [6,6]-phenyl-C71-butyric acid methyl ester (PCBM) films and poly(3-hexylthiophene) (P3HT):PCBM blend films employed as active layer in organic photovoltaic. The nanoscale morphology and the electrical characteristics of the P3HT:PCBM film can be controlled through organic polar solvent exposure, which exhibited with a short-circuit current density of 8.64 mA/cm2, an open circuit voltage of 0.63 V, and a power conversion efficiency of 3.29% under AM 1.5 illumination with a light intensity of 100 mW/cm2. By exposing the active layer films to organic polar solvent a favorable phase separation in the P3HT:PCBM films is obtained. The improved power conversion efficiency can be to the high conductivity and high surface area of the P3HT:PCBM layer treated with organic polar solvent. 相似文献
4.
Yung-Chung Chen Chih-Yu Hsu Czung-Yu Ho Yu-Tai Tao Jiann T. Lin 《Organic Electronics》2013,14(9):2290-2298
New conjugated copolymers (P1?P3) containing dipolar side chains connected to the main chain via triphenylamine donors have been synthesized and characterized. The side chains of these polymers have an electron deficient benzothiadiazole moiety in the spacer, but with different acceptors at the end. By changing the acceptor moieties of the side chain, the absorption spectra and HOMO/LUMO gaps of the polymers can be fine-tuned, ranging from 1.86 to 1.59 eV. Solution processed bulk heterojunction (BHJ) solar cells using these polymers as the donor and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) as the acceptor were fabricated and measured under 100 mW cm?2 of AM 1.5 illumination. The cell based on the blend of P1/PCBM (1:1, w/w) exhibited the highest power conversion efficiency of 1.78%, with open circuit voltage (Voc) = 0.79 V, short circuit current (Jsc) = 6.63 mA cm?2 and fill factor (FF) = 0.34, respectively. 相似文献
5.
G. Niu B. Vilquin N. Baboux C. Plossu L. Becerra G. Saint-Grions G. Hollinger 《Microelectronic Engineering》2009,86(7-9):1700-1702
This article reports on the epitaxy of crystalline high κ oxide Gd2O3 layers on Si(1 1 1) for CMOS gate application. Epitaxial Gd2O3 thin films have been grown by Molecular Beam Epitaxy (MBE) on Si(1 1 1) substrates between 650 and 750 °C. The structural and electrical properties were investigated depending on the growth temperature. The C–V measurements reveal that equivalent oxide thickness (EOT) equals 0.7 nm for the sample deposited at the optimal temperature of 700 °C with a relatively low leakage current of 3.6 × 10?2 A/cm2 at |Vg ? VFB| = 1 V. 相似文献
6.
Hoyoul Kong Jasmine Sinha Daniel Hoeft Stuart B. Kirschner Daniel H. Reich Howard E. Katz 《Organic Electronics》2013,14(3):703-710
Organic p–n bilayer photodiodes were produced by solution casting poly(3-hexylthiophene) (P3HT) from chlorobenzene and phenyl-C61-butyric acid methyl ester (PCBM):poly(4-chlorostyrene) (PClS) blends from the nearly orthogonal solvent dichloromethane onto flexible indium tin oxide (ITO)/polyester as a substrate. This is the first demonstration of PCBM–inert polymer blends for such a device. The electron mobility of a 90% PCBM–10% PClS blend was 3.5 × 10?3 cm2/V s in a field-effect transistor. The diodes showed a rectification ratio of 2.0 × 103 at ±2.0 V with a forward bias current density as high as 340 μA/cm2 at 2.0 V in the dark. Irradiation with various light sources (0.013–291 mW/cm2) under ambient atmosphere generated a linear increase in photocurrent. Photodiodes with thinner active layers showed larger photocurrent and relative photoresponse, probably because of lower series resistance and lower recombination probability. The reverse bias response was less dependent on device area than the forward bias response. Photocurrents from multiple devices in parallel were additive as expected. The results demonstrate a simple fabrication route to light detectors compatible with solution processes and flexible substrates. 相似文献
7.
A series of derivatives based on annelated β-oligothiophenes were synthesized and characterized as active layer in organic field-effect transistors (OFETs). Highest field-effect mobility of 0.52 V?1 s?1 for 2,5-dibiphenyl-dithieno[2,3-b:3′,2′-d]thiophene (DBP-DTT), 2.2 cm2 V?1 s?1 for 2,5-distyryl-dithieno[2,3-b:3′,2′-d]thiophene (DEP-DTT), and 0.16 cm2 V?1 s?1 for 1,4-di[2-dithieno[2,3-b:3′,2′-d] thiophen-2-yl-vinyl]benzene (DDTT-EP) were obtained, while 2,5-diphenyl-dithieno [2,3-b:3′,2′-d]thiophene (DP-DTT) presents no field-effect behaviors. Their thermal, optical and electrochemical properties, topographical and X-ray diffraction patterns of films, and the single crystal structures were also investigated. With the end-capping groups changing in these materials, the intermolecular interactions could transform from S–S in DP-DTT to S–C in DBP-DTT, to S–π in DEP-DTT, and to the coexisting of S–S and S–π in DDTT-EP. According to the device performances and the results of transfer integral calculations, it was revealed that S–π intermolecular interaction benefits not only improving the mobility but also reducing the threshold voltage (VT), while S–S intermolecular interaction is not favorable for promoting the mobility. 相似文献
8.
《Organic Electronics》2014,15(7):1650-1656
Poly(3-hexylthiophene)-Phenyl-C61-butyric acid methyl ester (P3HT–PCBM) composites find wide application in optoelectronic devices, especially bulk-hetero junction (BHJ) solar cells. These composites, even though could give efficient polymer solar cells with ∼4–5% power conversion efficiencies (PCE), a major problem of photo stability is associated with it and remains unsolved. P3HT–PCBM composite was found to be degrading on irradiation with ultraviolet radiation or a solar simulator providing AM1.5G illumination (1000 W m–2, 72 ± 2 °C or 330 W m−2, 25 °C), in presence of oxygen and moisture. Here, we have studied the photo stability of P3HT–PCBM under ambient conditions and showed that a new ternary composite, P3HT–PCBM–MWCNT (multi walled carbon nanotube) has superior photo stability even on extended UV–Vis exposure. A total of 7% (w/w) PCBM and 3% (w/w) MWCNT with respect to P3HT resulted in optimum stability. UV–Visible and fluorescence spectral analysis have been used to study the photo stability, both in solution state and solid/film state. Transmission electron micrograph (TEM) along with selected area electron diffraction (SAED) pattern and Field Emission Scanning Electron Microscopy (FE-SEM) micrographs have been used to show the well coating of MWCNT on P3HT–PCBM composite. Since MWCNT is one of the very important carbon based nanomaterial with several supreme characteristics, this new ternary composite has great importance for optoelectronic applications. 相似文献
9.
Chi-Yen Lin You-Ming Chen Hsiao-Fan Chen Fu-Chuan Fang Yu-Cheng Lin Wen-Yi Hung Ken-Tsung Wong Raymond C. Kwong Sean C. Xia 《Organic Electronics》2009,10(1):181-188
This paper describes the synthesis of three triaryldiamine derivatives presenting two thermally polymerizable trifluorovinyl ether groups that can be polymerized through thermal curing to form perfluorocyclobutyl (PFCB) polymers. These PFCB polymers, studied using time-of-flight techniques for the first time, exhibited remarkable non-dispersive hole-transport properties, with values of μh of ca. 10?4 cm2 V?1 s?1. When we employed these thermally polymerized polymers as hole-transport layers (HTLs) in electroluminescence devices containing tris(8-hydroxyquinolate) aluminum (Alq3) as the emission layer, we obtained high current densities (ca. 3400 mA cm?2), impressive brightnesses (5 × 104 cd m?2), and high external quantum efficiencies (EQEs = 1.43%). These devices exhibited the same turn-on voltage, but higher EQEs, relative to those incorporating the vacuum-processed model compound N,N′-di(1-naphthyl)-N,N′-diphenylbenzidine (α-NPD) (EQE = 1.37%) as the HTL under the same device structure. 相似文献
10.
Mihaela Girtan 《Organic Electronics》2013,14(1):200-205
New photoelectrical properties of poly(3-hexylthiophene-2,5-diyl), highly regioregular (P3HT): Methanofullerene Phenyl-C61-Butyric-Acid-Methyl-Ester [60] PCBM films were putted in evidence. For the first time the electrical conductivity dependencies on temperature in dark and under different illuminations were studied for the P3HT and P3HT:PCBM blend films. These dependencies shows reversible processes and a high sensitivity of the P3HT and P3HT:PCBM to light. The decrease of the resistivity at the exposure to light is of 18% for P3HT films and of 20% for P3HT:PCBM blend films, for a irradiation under 0.5 W/m2 white light at room temperature. By adding the fullerene molecules, in the 1:0.8 polymer:fullerene ratio, the electrical resistivity at room temperature of the blend films decrease compared to the polymer film by 40% in dark, and by 68% under 250 W/m2 white light irradiance.The decrease of the resistivity with the temperature is more pronounced in the presence of light indicating a photon activated process.The existence of the open circuit voltage was evidenced even for planar geometry photodiodes and the values of the open circuit voltage under 1000 W/m2 solar light illumination are coherent with the difference between the work functions of the electrodes. 相似文献
11.
Flávia P. Rosselli Welber G. Quirino Cristiano Legnani Vanessa L. Calil Kelly C. Teixeira Alexandre A. Leitão Rodrigo B. Capaz Marco Cremona Carlos A. Achete 《Organic Electronics》2009,10(8):1417-1423
We investigate the stability of tris-(8-hydroxyquinolinato) aluminum (Alq3) under UV photo degradation using a combination of experimental and theoretical techniques. Alq3 thin films were irradiated with He–Xe lamp discharges, as a function of the exposition time, at a wavelength λ = 307 nm. The irradiated and non-irradiated films were analyzed by Fourier transform infrared (FTIR) spectroscopy. The experimental FTIR spectrum of the exposed sample exhibits a band at 1697 cm?1, attributed to a carbonyl group. Theoretical calculations of Gibbs free energy and molecular vibrational properties for a variety of possible degradation products allow us to determine the most likely products and produce insight into the degradation mechanisms. 相似文献
12.
《Organic Electronics》2014,15(4):913-919
Efficient bulk-heterojunction polymer solar cells based on poly(3-hexylthiophene) (P3HT) blended with a fullerene derivative, [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) were fabricated in inverted configuration by using copper phthalocyanine-3,4′,4′′,4′′′tetra-sulfonated acid tetrasodium salt (TS-CuPc) as the electron collecting layer and MoO3 as hole collecting layer. TS-CuPc is observed to be critical for the device performance, significantly enhancing the Jsc and the PCE compared to devices based on TiOx. The optimal thicknesses of MoO3 and TS-CuPc were 10 nm and 15 nm, respectively. Based on these optimal parameters, the PCE of 3.6% was obtained compared to 3.4% for the reference TiOx/P3HT:PCBM/MoO3/Ag. 相似文献
13.
Solution processable diketopyrrolopyrrole (DPP)-bithiophene polymers (PDBT) with long branched alkyl side chains on the DPP unit are synthesized. These polymers have favourable highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels for the injection and transport of both holes and electrons. Organic thin film transistors (OTFTs) using these polymers as semiconductors and gold as source/drain electrodes show typical ambipolar characteristics with very well balanced high hole and electron mobilities (μh = 0.024 cm2 V?1 s?1 and μe = 0.056 cm2 V?1 s?1). These simple and high-performing polymers are promising materials for ambipolar organic thin film transistors for low-cost CMOS-like logic circuits. 相似文献
14.
Sachetan M. Tuladhar Marc Sims Stelios A. Choulis Christian B. Nielsen Wayne. N. George Joachim H.G. Steinke Donal D.C. Bradley Jenny Nelson 《Organic Electronics》2009,10(4):562-567
We report on studies of poly-(2,5-dihexyloxy-p-phenylenevinylene) (PDHeOPV), a symmetric side-chain polymer, as a potential new donor material for polymer:fullerene blend solar cells. We study the surface morphology of blend films of PDHeOPV with PCBM, the transport properties of the blend films, and the performance of photovoltaic devices made from such blend films, all as a function of PCBM content. In each case, results are compared with those obtained using the asymmetric side chain polymer, poly[2-methoxy-5-(3,7-dimethyloctyloxy)-1,4-phenylenevinylene] (MDMO-PPV), in order to investigate the influence of polymer side chain symmetry on solar cell performance. AFM images show that large PCBM aggregates appear at lower PCBM content (50 wt.% PCBM) for PDHeOPV:PCBM than for MDMO-PPV:PCBM (67 wt.% PCBM) blend films. Time-of-Flight (ToF) mobility measurements show that charge mobilities depend more weakly on PCBM content in PDHeOPV:PCBM than in MDMO:PPV:PCBM, with the result that at high PCBM content the mobilities in PDHeOPV:PCBM are significantly lower than in MDMO:PPV:PCBM blend films, despite the higher mobilities in pristine PDHeOPV compared to pristine MDMO-PPV. Photovoltaic devices show significantly lower power conversion efficiency (~0.93%) for PDHeOPV:PCBM (80 wt.% PCBM) blend films than for MDMO-PPV:PCBM (2.2% at 80 wt.% PCBM) blends. This is attributed to the relatively poor transport properties of the PDHeOPV:PCBM blend, which limit the optimum thickness of the photoactive layer in PDHeOPV:PCBM blend devices. The behaviour is tentatively attributed to a higher tendency for the symmetric side-chain polymer chains to aggregate, resulting in poorer interaction with the fullerene and poorer network formation for charge transport. 相似文献
15.
Anusit Keawprajak Wantana Koetniyom Phimwipha Piyakulawat Kanpitcha Jiramitmongkon Sirapat Pratontep Udom Asawapirom 《Organic Electronics》2013,14(1):402-410
A solvent additive in PEDOT:PSS solution is one of many methods to improve the conductivity of the poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) films. We explore a new type of the solvent additive, namely tetramethylene sulfone (TMS), for the fabrication of the PEDOT:PSS conductive layer in the ITO/PEDOT:PSS/P3HT:PCBM/TiOx/Al polymer photovoltaic cells, in comparison to a more common dimethyl sulfoxide (DMSO) solvent additive. At optimal conditions, the TMS additive at 10 wt.% has been found to enhance the conductivity of pristine PEDOT:PSS films from 0.04 S/cm up to approximately 189 S/cm, compared with the highest conductivity for the case of the DMSO additive at 15 wt.% of 117 S/cm. Possible mechanisms of this conductivity enhancement, relating to the polymer conformation and the film morphology, have been investigated by Raman spectroscopy, X-ray diffraction, atomic force microscopy, and transmission electron microscopy. The performance of the polymer photovoltaic cells fabricated with the solvent additives PEDOT:PSS films follows a similar trend to the conductivity of the films as a function of the additive concentration. The additives mainly lead to greater short circuit current density (Jsc) of the photovoltaic cells. The highest power conversion efficiency (PCE) of 2.24% of the device has been obtained with the 10 wt.% TMS additive of, compared to the PCE of 1.48% for the standard device without solvent additive. 相似文献
16.
Poly (3-hexylthiophene-2, 5-diyl) (P3HT) and its blend with Phenyl-C61-Butyric acid-Methyl-Ester (PCBM) and fullerene (C60) thin films were prepared and their electrical properties for memory applications were studied. Due to doping, a sharp decrease in the resistance for a P3HT:PCBM:C60 device was observed at around 70 °C which makes it useful for thermal switching applications. Addition of C60 to P3HT:PCBM blend gave a high value for RRESET/RSET in thermal switching. For bias switching, threshold voltage reduces to 1.4 V from 25 V with the addition of C60 to P3HT layer. 相似文献
17.
Yuguang Lv QiuPing Li Yiying Zhang Yuze Han Hong Liu Guiyan Wang Jinlian Li Dongmei Wu Zhiwei Yang Lingxuan Wang Jie Xie 《Solid-state electronics》2008,52(8):1149-1153
Rare-earth ternary complexes EuXLa1?X(TTA)3Dipy (X = 0, 0.1, 0.25, 0.5, 0.75, 0.9, 1.0) were synthesized. Characterization with DTA-TG, IR, elemental analysis and fluorescent spectra had also been carried out. It is found that the enhanced luminescence of Eu3+ ions by La3+ ions occurs in ternary complexes, and when X = 0.25, Eu0.25La0.75(TTA)3Dipy has the highest luminescence efficiency and lifetime. It is proved by TG curve that the complexes are stable, and we monitored the spectra of EuXLa1?X(TTA)3Dipy[PVK:EuXLa1?X(TTA)3Dipy/BCP/AlQ/Al] at the different rate r min?1. The results showed that the La3+ ion acts as an energy transfer bridge that helps energy transfer from PVK to Eu3+. 相似文献
18.
Zhuqi Chen Fei Ding Feng Hao Zuqiang Bian Bei Ding Yezi Zhu Fangfang Chen Chunhui Huang 《Organic Electronics》2009,10(5):939-947
A neutral ligand 9-(4-tert-butylphenyl)-3,6-bis(diphenylphosphineoxide)-carbazole (DPPOC) and its complex Tb(PMIP)3DPPOC (A, where PMIP stands for 1-phenyl-3-methyl-4-isobutyryl-5-pyrazolone) were synthesized. DPPOC has a suitable lowest triplet energy level (24,691 cm?1) for the sensitization of Tb(III) (5D4: 20,400 cm?1) and a significantly higher thermal stability (glass transition temperature 137 °C) compared with the familiar ligand triphenylphosphine oxide (TPPO). Experiments revealed that the emission layer of the Tb(PMIP)3DPPOC film could be prepared by vacuum co-deposition of the complex Tb(PMIP)3(H2O)2 (B) and DPPOC (molar ratio = 1:1). The electroluminescent (EL) device ITO/N,N′-diphenyl-N,N′-bis(1-naphthyl)-1,1′-diphenyl-4,4′-diamine (NPB; 10 nm)/Tb(PMIP)3 (20 nm)/co-deposited Tb(PMIP)3DPPOC (30 nm)/2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP; 10 nm)/tris(8-hydroxyquinoline) (AlQ; 20 nm)/Mg0.9Ag0.1 (200 nm)/Ag (80 nm) exhibited pure emission from terbium ions, even at the highest current density. The highest efficiency obtained was 16.1 lm W?1, 36.0 cd A?1 at 6 V. At a practical brightness of 119 cd m?2 (11 V) the efficiency remained above 4.5 lm W?1, 15.7 cd A?1. These values are a significant improvement over the previously reported Tb(PMIP)3(TPPO)2 (C). 相似文献
19.
Xinping Liu Ji Zhang Peng Tang Gui Yu Zhiyong Zhang Huajie Chen Ya Chen Bin Zhao Songting Tan Ping Shen 《Organic Electronics》2012,13(9):1671-1679
A new donor–acceptor (D?A) copolymer (PIPY–DTBTA) containing 6,12-dihydro-diindeno[1,2-b;1′,2′-e]pyrazine donor and benzotriazole acceptor was synthesized and characterized for multifunctional applications in organic field-effect transistors (OFETs), polymer solar cells (PSCs) and polymer light-emitting diodes (PLEDs). The polymer exhibits high molecular weights, excellent film-forming ability, a deep HOMO energy level, and good solution processability. Solution-processed thin film OFETs based on this polymer revealed good p-type characteristic with a high hole mobility up to 0.0521 cm2 V?1 s?1. Bulk-heterojunction PSCs comprising this polymer and PC61BM gave a power conversion efficiency (PCE) of 0.77%. The single-layer PLEDs based on PIPY–DTBTA emitted a yellow–red light with a maximum brightness of 385 cd m?2 at the turn-on voltage of 6 V. 相似文献
20.
We have demonstrated high performance inkjet-printed n-channel thin-film transistors (TFTs) using C60 fullerene as a channel material. Highly uniform amorphous C60 thin-film patterns were fabricated on a solution-wettable polymer gate dielectric layer by inkjet-printing and vacuum drying process. Fabricated C60 TFTs shows great reproducibility and high performance; field-effect mobilities of 2.2–2.4 cm2 V?1 s?1, threshold voltages of 0.4–0.6 V, subthreshold slopes of 0.11–0.16 V dec?1 and current on/off ratio of 107–108 in a driving voltage of 5 V. This is due to the efficient annealing process that extracting the solvent residue and the formation of low trap-density gate dielectric surface. 相似文献