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1.
Graphene: Enhanced Vertical Charge Transport in a Semiconducting P3HT Thin Film on Single Layer Graphene (Adv. Funct. Mater. 5/2015) 
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下载免费PDF全文 Vasyl Skrypnychuk Nicolas Boulanger Victor Yu Michael Hilke Stefan C. B. Mannsfeld Michael F. Toney David R. Barbero 《Advanced functional materials》2015,25(5):653-653
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Anthony J. Morfa Alexandre M. Nardes Sean E. Shaheen Nikos Kopidakis Jao van de Lagemaat 《Advanced functional materials》2011,21(13):2580-2586
The charge‐collection dynamics in poly(3‐hexylthiophene:[6,6]‐phenyl‐C61‐butyric acid methyl ester (P3HT:PCBM) bulk heterojunctions are studied in thick (>1 μm) devices using time‐of‐flight measurements and external quantum‐efficiency measurements. The devices show Schottky‐diode behavior with a large field‐free region in the device. Consequently, electron transport occurs by diffusion in the bulk of the active layer. At high applied biases where the depletion region spans the entire active layer, normal time‐of‐flight transients are observed from which the electron mobility can be determined. Here, the electron mobility follows Poole–Frenkel behavior as a function of field. At lower applied biases, where the depletion region only spans a small portion of the active layer, due to a high density of dark holes, the recombination kinetics follow a first‐order rate law with a rate constant about two orders of magnitude lower than that predicted by Langevin recombination. 相似文献
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Yuefang Wei Yuyan Zhang Yutong Ren Bing Zhang Yi Yuan Jing Zhang Peng Wang 《Advanced functional materials》2023,33(43):2307501
Achieving the desired thermomechanical properties for highly solution-processable organic semiconductors is challenging but crucial for heat tolerance of emerging optoelectronic devices. To this end, the successful synthesis of triphenylene–ethylenedioxythiophene-dimethoxytriphenylamine (TP–ETPA), a star-shaped organic semiconductor, is reported through a direct arylation reaction that involves ETPA, an electron donor, being grafted densely onto TP, which possesses six electron-equivalent functionalization sites. Remarkably, TP–ETPA exhibits significantly improved hole mobility compared to 2,2′,7,7′-tetrakis(N,N-di-p-methoxyphenyl-amine)-9,9′-spirobifluorene (spiro-OMeTAD) at a given hole density, owing to its lower energetic disorder, larger average centroid distance, and smaller reorganization energy. TP–ETPA, with a molecular weight of 2888 Da and lacking flexible chains, demonstrates extraordinary solubility in nonpolar solvents, enabling the formation of dense, pinhole-free films through solution codeposition with an air-doping promoter. By utilizing the p-doped TP–ETPA composite as the hole transport layer, perovskite solar cells with an average power conversion efficiency of 23.4% are successfully fabricated. Notably, these devices display significantly enhanced operational stability and thermal stability at 85 °C. Molecular dynamics simulations reveal that the TP–ETPA-based hole transport layer possesses a high cohesive energy density, resulting in a large elastic modulus and slow diffusion of external species. 相似文献
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Highly thermal stable organic bulk heterojunction (OBHJ) photovoltaic cells are demonstrated with crosslinkable open‐cage fullerenes ( COF ) as additives in the active layer. Partial incorporation of COF , ≈10–15 wt% with weight ratio of P3HT: PC61BM = 1:0.9, builds up three‐dimensional local borders upon heating treatment at 150 °C for 10 min. This process induces crosslinking chemical reaction through activating the styryl moiety in COF and reduces phase aggregation rates of fullerenes materials. Supported by statistics of devices degradation data analysis and optical microscopy study, the devices with COF show longer lifetime with keeping their efficiency (t = 144 h) under accelerated heating test at 150 °C, while PCE of normal devices without COF drop dramatically. These results demonstrate that the thermally crosslinkable COF is an excellent additive for highly thermal stable and durable OPVs applications. 相似文献
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Accurate measurements of the valence electronic structures of organic semiconductors are important for the development and understanding of organic electronic devices, materials, and interfaces. Ultraviolet photoelectron spectroscopy (UPS) is a well-established technique for probing valence electronic structures; however, many organic semiconductors undergo rapid sample degradation upon exposure to traditional laboratory-based vacuum ultraviolet (VUV) photon sources. Here, we report on a novel VUV photon source for UPS measurements that utilizes H Lyman-α emission with a narrow linewidth and a widely tunable intensity, and apply it to a number of organic materials of interest to show its ability to overcome this hurdle of sample degradation. Furthermore, the H Lyman-α source displays no measureable higher energy emission lines, which significantly reduces the background over typical He I discharge sources and allows for the onset of the density of states to be clearly observed over several orders of magnitude. 相似文献
7.
Ke Zhang Michal Borkowski Philipp Wucher Pierre M. Beaujuge Jasper J. Michels Paul. W. M. Blom Tomasz Marszalek Wojciech Pisula 《Advanced Electronic Materials》2021,7(8):2100397
Meniscus-guided coating (MGC) is an efficient and promising route to grow small molecule and polymer organic semiconductors (OSCs) into highly ordered and uniaxially orientated thin films for electronic applications. In this work, the impact of domain size and molecular order on the charge carrier transport in field-effect transistors for a molecular organic semiconductor 4-tolyl-bithiophenyl-diketopyrrolopyrrole (DPP(Th2Bn)2) is investigated. The spherulitic domain growth of DPP(Th2Bn)2 in thin films is controlled in the evaporative regime of zone-casting by varying the substrate velocity. The decrease of coating velocity leads to a lower nucleation density and larger domain size of DPP(Th2Bn)2. At sufficiently low velocity, the spherulitic domains first elongate and then uniaxially grow in the coating direction. Although at the same time the molecular order decreases due to higher film thickness, the charge carrier transport improves for larger domain size and reduced density of boundaries in the transistor channel. These results provide insight on the relation between domain growth, molecular organization, and charge carrier transport in zone-cast OSC thin films that are important for the upscaling of the technique for practical applications. 相似文献
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In this article, poly(3-hexylthiophene) (P3HT) based thin film transistors with Ti capped source and drain electrodes (S/D) was employed to have an insight into the mechanism of bulk current effect, which led to poor subthreshold swing and large off current. Our newly developed PTFTs do show greater characteristics in the aspects of on/off current ratio and subthreshold swing than those with the conventional Au/Ti S/D. In order to explain the results, we propose that the bulk current is composed of two components, i.e., side-wall and top-face injections. We ascribe the improvements to the reduction of top-face injection bulk current due to the larger injection barrier between the P3HT and Ti. As comparing the PTFTs with Ti capped laterally grown multi-wall carbon nanotube (MWCNT) S/D with the PTFTs with MWCNT S/D, we also observe similar tendency of bulk current reduction. From the viewpoint of device operation, better subthreshold swing and smaller off current result in faster device switching and lower power consumption. By this new approach of S/D structure, there are two and 20 times improvements on the subthreshold swing and off current, respectively, although the reduction of the bulk current also leads to a slight decrease of the on-current. 相似文献
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Xi Wang Xinqiang Cao Laure Bourgeois Hasigaowa Guan Shimou Chen Yeteng Zhong Dai‐Ming Tang Huiqiao Li Tianyou Zhai Liang Li Yoshio Bando Dmitri Golberg 《Advanced functional materials》2012,22(13):2682-2690
A new facile route to fabricate N‐doped graphene‐SnO2 sandwich papers is developed. The 7,7,8,8‐tetracyanoquinodimethane anion (TCNQ?) plays a key role for the formation of such structures as it acts as both the nitrogen source and complexing agent. If used in lithium‐ion batteries (LIBs), the material exhibits a large capacity, high rate capability, and excellent cycling stability. The superior electrochemical performance of this novel material is the result from its unique features: excellent electronic conductivity related to the sandwich structure, short transportation length for both lithium ions and electrons, and elastomeric space to accommodate volume changes upon Li insertion/extraction. 相似文献
11.
Ashish Garg Shailendra Kumar Gupta Jacek J. Jasieniak Th. Birendra Singh Scott E. Watkins 《Progress in Photovoltaics: Research and Applications》2015,23(8):989-996
We report on the use and stability of solution‐processed molybdenum oxide (sMoOx) thin films as anode‐modifying layers to replace conventionally used poly(3,4‐ethyldioxythiophene)/poly(styrenesulfonate) (PEDOT/PSS) layers in poly(3‐hexylthiophene):[6,6]‐phenyl C61 butyric acid methyl ester (P3HT/PC61BM) bulk heterojunction organic solar cells. Our results show that while as prepared devices using the two anode‐modifying layers possess similar performances, the sMoOx devices exhibit a staggering 20‐fold stability improvement in its performance half‐life compared with PEDOT/PSS devices, ~3400 h versus ~150 h, respectively. A further comparison of the stability between encapsulated and unencapsulated devices demonstrates the necessity for protection from atmospheric moisture and oxygen but again highlights the lucrative nature of sMoOx as a protective anode‐modifying layer compared with PEDOT/PSS even under ambient conditions. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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N. Mastour Z. Ben Hamed A. Benchaabane M.A. Sanhoury F. Kouki 《Organic Electronics》2013,14(8):2093-2100
The effects of ZnSe quantum dot (Qd) concentration on the fluorescence in Poly(3-hexylthiophene-2,5-diyl) matrix (P3HT) are investigated. The fluorescence spectra were found to be very dependant on the Qd concentration and light emission is significantly enhanced by incorporation of ZnSe Qd in the polymer matrix. Using a theoretical model for hybrid (organic–inorganic) system, interesting numerical results for the light emission and relative quantum efficiency as a function of ZnSe Qd concentration were obtained. The theoretical results were found to be in good agreement with experimental data. 相似文献
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Brendan T. O'Connor Obadiah G. Reid Xinran Zhang R. Joseph Kline Lee J. Richter David J. Gundlach Dean M. DeLongchamp Michael F. Toney Nikos Kopidakis Garry Rumbles 《Advanced functional materials》2014,24(22):3422-3431
The morphological origin of anisotropic charge transport in uniaxially strain aligned poly(3‐hexylthiophene) (P3HT) films is investigated. The macroscale field effect mobility anisotropy is measured in an organic thin film transistor (OTFT) configuration and compared to the local aggregate P3HT mobility anisotropy determined using time‐resolved microwave conductivity (TRMC) measurements. The field effect mobility anisotropy in highly aligned P3HT films is substantially higher than the local mobility anisotropy in the aggregate P3HT. This difference is attributed to preferentially aligned polymer tie‐chains at grain boundaries that contribute to macroscale charge transport anisotropy but not the local anisotropy. The formation of sharp grains between oriented crystalline P3HT, through tie chain removal by thermal annealing the strained aligned films, results in an order of magnitude drop in the measured field effect mobility for charge transport parallel to the strain direction. The field effect mobility anisotropy is cut in half while the local mobility anisotropy remains relatively constant. The local mobility anisotropy is found to be surprisingly low in the aligned films, suggesting that the π?π stacking direction supports charge carrier mobility on the same order of magnitude as that in the intrachain direction, possibly due to poor intrachain mobility through chain torsion. 相似文献
14.
Tao Chen Weihua Hu Junling Song Guan Hong Guai Chang Ming Li 《Advanced functional materials》2012,22(24):5245-5250
The microstructures of photo‐ and counter‐electrodes play critical roles in the performance of dye‐sensitized solar cells (DSSCs). In particular, various interfaces, such as fluorinated‐tin oxide (FTO)/TiO2, TiO2/TiO2, and TiO2/electrolyte, in DSSCs significantly affect the final power conversion efficiency (PCE). However, research has generally focused more on the design of various nanostructured semiconducting materials with emphasis on optimizing chemical or/and physical properties, and less on these interface functionalizations for performance improvement. This work explores a new application of graphene to modify the interface of FTO/TiO2 to suppress charge recombination. In combination with interfaces functionalization of TiO2/TiO2 for low charge‐transport resistance and high charge‐transfer rate, the final PCE of DSSC is remarkably improved from 5.80% to 8.13%, achieving the highest efficiency in comparison to reported graphene/TiO2‐based DSSCs. The method of using graphene to functionalize the surface of FTO substrate provides a better alternative method to the conventional pre‐treatment through hydrolyzing TiCl4 and an approach to reduce the adverse effect of microstructural defect of conducting glass substrate for electronic devices. 相似文献
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D. M. Marathe H. S. Tarkas M. S. Mahajan G. S. Lonkar S. R. Tak J. V. Sali 《半导体学报》2016,37(9):093003-4
We here present a way of preparing the polymer:fullerene BHJ using dual feed method which can lead to formation of pure phases. In this report, we present results of our initial experiments in this direction. The effect of process parameters on the thickness and surface roughness of the active layer has been discussed. The structural and optical properties have been studied using the optical microscope, UV-visible spectroscopy and photoluminescence spectroscopy. Significant PL quenching indicates efficient charge separation in the BHJ formed using this technique. We have also compared the BHJ thin films prepared with this dual feed ultrasonic technique with the single feed spray method. The BHJ formed using this technique has been used as an active layer in OSC. 相似文献
16.
《Microelectronics Reliability》2014,54(12):2766-2774
In this study, the gold/poly(3-hexylthiophene):[6,6]-phenyl C61 butyric acid methyl ester/n-type silicon (Au/P3HT:PCBM/n-Si) metal–polymer–semiconductor (MPS) Schottky barrier diodes (SBDs) were investigated in terms of the effects of PCBM concentration on the electrical parameters. The forward and reverse bias current–voltage (I–V) characteristics of the Au/P3HT:PCBM/n-Si MPS SBDs fabricated by using the different P3HT:PCBM mass ratios were studied in the dark, at room temperature. The main electrical parameters, such as ideality factor (n), barrier height (ΦB0), series resistance (Rs), shunt resistance (Rsh), and density of interface states (Nss) were determined from I–V characteristics for the different P3HT:PCBM mass ratios (2:1, 6:1 and 10:1) used diodes. The values of n, Rs, ΦB0, and Nss were reduced, while the carrier mobility and current were increased, by increasing the PCBM concentration in the P3HT:PCBM organic blend layer. The ideal values of electrical parameters were obtained for 2:1 P3HT:PCBM mass ratio used diode. This shows that the electrical properties of MPS diodes strongly depend on the PCBM concentration of the P3HT:PCBM organic layer. Moreover, increasing the PCBM concentration in P3HT:PCBM organic blend layer improves the quality of the Au/P3HT:PCBM/n-Si (MPS) SBDs which enables the fabrication of high-quality electronic and optoelectronic devices. 相似文献
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Hole injection barriers at the regioregular-poly-3(hexylthiophene) (RR-P3HT)/metal (Cu or Ag) interface were investigated using the accumulated charge measurement (ACM). Thermal annealing of RR-P3HT at 55 °C decreased the injection barrier. RR-P3HT thermally annealed in N2 forms an ohmic contact with Ag and a Schottky contact with Cu. The obtained values of the injection barriers, ϕB were well expressed by the Mott-Schottky rule, i.e., ϕB = IE - Wm′, where IE is the ionization energy of RR-P3HT and Wm′ is the work function of the metal electrode in air. The effect of the large vacuum level shift, reported in UPS studies conducted under ultrahigh vacuum, was not observed. 相似文献
18.
碳电极具有成本低、印刷方便、可有效隔离水氧等优点,因此有望利用碳电极材料实现低成本、高稳定性的钙钛矿太阳电池。无空穴传输层的传统碳基钙钛矿太阳电池面临着空穴提取率低、电子逆向传输,钙钛矿和碳电极界面的载流子复合等问题。文章引入聚(3-己基噻吩)(P3HT)作为器件的空穴传输层,使碳基钙钛矿太阳电池ITO/SnO2/MAPbI3/P3HT/Carbon的光伏性能得到了显著改善:器件的光电转化效率从11.16% 提高到13.37%。在氮气环境下,连续光照1000h,太阳电池的光电转化效率可保持初始值的87%,而传统器件在光照500h后,其光电转化效率已下降至初始值的60%。 相似文献
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《Advanced Electronic Materials》2018,4(9)
The highly efficient charge generation and transport is realized by simply stacking several 1,4,5,8,9,11‐hexa‐azatriphenylene hexacarbonitrile (HAT‐CN)/4,4′,4″‐tris(N‐3‐methylphenyl‐N‐phenylamino) triph‐enylamine (m‐MTDATA) organic heterojunctions in series. Mechanism analysis confirms that the highly effective charge transport property benefits from the efficient charge generation and recombination processes at the HAT‐CN/m‐MTDATA interfaces. It is found that the efficient multialternating organic heterojunctions can be used not only as hole and electron transporters to supply large charge injection, but also as excellent charge generation layer (CGL) to fabricate high‐performance tandem organic light‐emitting diodes (OLEDs). The resulting red phosphorescent OLEDs by simultaneously using the multialternating organic heterojunctions as hole and electron transporters realize the power efficiency (PE) of 36.7 lm W−1, current efficiency (CE) of 28.0 cd A−1, and external quantum efficiency (EQE) of 15.4%, whereas the PE, CE, and EQE, respectively, reach 37.1 lm W−1, 56.0 cd A−1, and 31.8% when simultaneously using the multialternating organic heterojunctions as hole and electron transporters and CGL to fabricate tandem red phosphorescent OLEDs, indicating the validity of the multialternating organic heterojunctions as the charge generator and transporters. The results provide us a totally new way of fabricating high‐performance OLEDs. 相似文献
20.
Kui Zhao Hadayat Ullah Khan Ruipeng Li Yisong Su Aram Amassian 《Advanced functional materials》2013,23(48):6024-6035
The influence of polymer entanglement on the self‐assembly, molecular packing structure, and microstructure of low‐Mw (lightly entangled) and high‐Mw (highly entangled) poly (3‐hexylthiophene) (P3HT), and the carrier transport in thin‐film transistors, are investigated. The polymer chains are gradually disentangled in a marginal solvent via ultrasonication of the polymer solution, and demonstrate improved diffusivity of precursor species (coils, aggregates, and microcrystallites), enhanced nucleation and crystallization of P3HT in solution, and self‐assembly of well‐ordered and highly textured fibrils at the solid–liquid interface. In low‐Mw P3HT, reducing chain entanglement enhances interchain and intrachain ordering, but reduces the interconnectivity of ordered domains (tie molecules) due to the presence of short chains, thus deteriorating carrier transport even in the face of improving crystallinity. Reducing chain entanglement in high‐Mw P3HT solutions increases carrier mobility up to ≈20‐fold, by enhancing interchain and intrachain ordering while maintaining a sufficiently large number of tie molecules between ordered domains. These results indicate that charge carrier mobility is strongly governed by the balancing of intrachain and interchain ordering, on the one hand, and interconnectivity of ordered domains, on the other hand. In high‐Mw P3HT, intrachain and interchain ordering appear to be the key bottlenecks to charge transport, whereas in low‐Mw P3HT, the limited interconnectivity of the ordered domains acts as the primary bottleneck to charge transport. 相似文献