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Regina M. Kluge Nitin Saxena Wei Chen Volker Krstgens Matthias Schwartzkopf Qi Zhong Stephan V. Roth Peter Müller‐Buschbaum 《Advanced functional materials》2020,30(28)
Thermoelectric generators pose a promising approach in renewable energies as they can convert waste heat into electricity. In order to build high efficiency devices, suitable thermoelectric materials, both n‐ and p‐type, are needed. Here, the n‐type high‐mobility polymer poly[N,N′‐bis(2‐octyldodecyl)naphthalene‐1,4,5,8‐bis(dicarboximide)‐2,6‐diyl]‐alt‐5,5′‐(2,2′‐bithiophene) (P(NDI2OD‐T2)) is focused upon. Via solution doping with 4‐(1,3‐dimethyl‐2,3‐dihydro‐1H‐benzoimidazol‐2‐yl)‐N,N‐diphenylaniline (N‐DPBI), a maximum power factor of (1.84 ± 0.13) µW K?2 m?1 is achieved in an in‐plane geometry for 5 wt% dopant concentration. Additionally, UV–vis spectroscopy and grazing‐incidence wide‐angle X‐ray scattering are applied to elucidate the mechanisms of the doping process and to explain the discrepancy in thermoelectric performance depending on the charge carriers being either transported in‐plane or cross‐plane. Morphological changes are found such that the crystallites, built‐up by extended polymer chains interacting via lamellar and π–π stacking, re‐arrange from face‐ to edge‐on orientation upon doping. At high doping concentrations, dopant molecules disturb the crystallinity of the polymer, hindering charge transport and leading to a decreased power factor at high dopant concentrations. These observations explain why an intermediate doping concentration of N‐DPBI leads to an optimized thermoelectric performance of P(NDI2OD‐T2) in an in‐plane geometry as compared to the cross‐plane case. 相似文献
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A. Werner F. Li K. Harada M. Pfeiffer T. Fritz K. Leo S. Machill 《Advanced functional materials》2004,14(3):255-260
We present an approach to stable n‐type doping of organic matrices using organic dopants. In order to circumvent stability limitations inherent to strong organic donors, we produce the donor from a stable precursor compound in situ. As an example, the cationic dye pyronin B chloride is studied as a dopant in a 1,4,5,8‐naphthalene tetracarboxylic dianhydride (NTCDA) matrix. Conductivities of up to 1.9 × 10–4 S cm–1 are obtained for doped NTCDA, two orders of magnitude higher than the conductivity of NTCDA doped with bis(ethylenedithio)‐tetrathiafulvalene as investigated previously, and four orders of magnitude higher than nominally undoped NTCDA films. Field‐effect measurements are used to prove n‐type conduction and to study the doping effect further. The findings are interpreted using a model of transport in disordered solids using a recently published model. Combined FTIR, UV‐vis, and mass spectroscopy investigations suggest the formation of leuco pyronin B during sublimation of pyronin B chloride. 相似文献
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Unconventional Molecular Weight Dependence of Charge Transport in the High Mobility n‐type Semiconducting Polymer P(NDI2OD‐T2) 下载免费PDF全文
Masrur M. Nahid Rukiya Matsidik Adam Welford Eliot Gann Lars Thomsen Michael Sommer Christopher R. McNeill 《Advanced functional materials》2017,27(9)
The charge transport and microstructural properties of five different molecular weight (MW) batches of the naphthalenediimide‐thiophene copolymer P(NDI2OD‐T2) are investigated. In particular, the field‐effect transistor (FET) performance and thin‐film microstructure of samples with MW varying from Mn = 10 to 41 kDa are studied. Unlike conventional semiconducting polymers such as poly(3‐hexylthiophene) where FET mobility dramatically drops with decreasing molecular weight, the FET mobility of P(NDI2OD‐T2)‐based transistors processed from 1,2‐dichlorobenzene is found to increase with decreasing MW. Using a combination of grazing‐incidence wide‐angle X‐ray scattering, near‐edge X‐ray absorption fine‐structure spectroscopy, atomic force microscopy, and resonant soft X‐ray scattering, the increase in FET mobility with decreasing MW is attributed to the pronounced increase in the orientational correlation length (OCL) with decreasing MW. In particular, the OCL is observed to systematically increase from <100 nm for the highest MW samples to ≈1 µm for the lowest MW samples. The improvement in OCL and hence mobility for low MW samples is attributed to the lack of aggregation of low MW chains in solution promoting backbone ordering, with the pre‐aggregation of chains in 1,2‐dichlorobenzene found to suppress longer‐range liquid crystalline order. 相似文献
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Thin Films: Polymer‐Modified Mesoporous Silica Thin Films for Redox‐Mediated Selective Membrane Gating (Adv. Funct. Mater. 11/2014) 下载免费PDF全文
Johannes Elbert Fabio Krohm Christian Rüttiger Sandra Kienle Haiko Didzoleit Bizan N. Balzer Thorsten Hugel Bernd Stühn Markus Gallei Annette Brunsen 《Advanced functional materials》2014,24(11):1493-1493
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Zhen‐Hua Ge Yang Qiu Yue‐Xing Chen Xiaoyu Chong Jing Feng Zi‐Kui Liu Jiaqing He 《Advanced functional materials》2019,29(28)
SnSe has attracted much attention due to the excellent thermoelectric (TE) properties of both p‐ and n‐type single crystals. However, the TE performance of polycrystalline SnSe is still low, especially in n‐type materials, because SnSe is an intrinsic p‐type semiconductor. In this work, a three‐step doping process is employed on polycrystalline SnSe to make it n‐type and enhance its TE properties. It is found that the Sn0.97Re0.03Se0.93Cl0.02 sample achieves a peak ZT value of ≈1.5 at 798 K, which is the highest ZT reported, to date, in n‐type polycrystalline SnSe. This is attributed to the synergistic effects of a series of point defects: . In those defects, the compensates for the intrinsic Sn vacancies in SnSe, the acts as a donor, the acts as an acceptor, all of which contribute to optimizing the carrier concentration. Rhenium (Re) doping surprisingly plays dual‐roles, in that it both significantly enhances the electrical transport properties and largely reduces the thermal conductivity by introducing the point defects, . The method paves the way for obtaining high‐performance TE properties in SnSe crystals using multipoint‐defect synergy via a step‐by‐step multielement doping methodology. 相似文献
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Conjugated Polymers: Systematic Investigation of Side‐Chain Branching Position Effect on Electron Carrier Mobility in Conjugated Polymers (Adv. Funct. Mater. 40/2014) 下载免费PDF全文
Jin‐Hu Dou Yu‐Qing Zheng Ting Lei Shi‐Ding Zhang Zhi Wang Wen‐Bin Zhang Jie‐Yu Wang Jian Pei 《Advanced functional materials》2014,24(40):6404-6404
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A Versatile Method to Fabricate Highly In‐Plane Aligned Conducting Polymer Films with Anisotropic Charge Transport and Thermoelectric Properties: The Key Role of Alkyl Side Chain Layers on the Doping Mechanism 下载免费PDF全文
Amer Hamidi‐Sakr Laure Biniek Jean‐Louis Bantignies David Maurin Laurent Herrmann Nicolas Leclerc Patrick Lévêque Vishnu Vijayakumar Nicolas Zimmermann Martin Brinkmann 《Advanced functional materials》2017,27(25)
A general method is proposed to produce oriented and highly crystalline conducting polymer layers. It combines the controlled orientation/crystallization of polymer films by high‐temperature rubbing with a soft‐doping method based on spin‐coating a solution of dopants in an orthogonal solvent. Doping rubbed films of regioregular poly(3‐alkylthiophene)s and poly(2,5‐bis(3‐dodecylthiophen‐2‐yl)thieno[3,2‐b ]thiophene) with 2,3,5,6‐tetrafluoro‐7,7,8,8‐tetracyanoquinodimethane (F4TCNQ) yields highly oriented conducting polymer films that display polarized UV–visible–near‐infrared (NIR) absorption, anisotropy in charge transport, and thermoelectric properties. Transmission electron microscopy and polarized UV–vis–NIR spectroscopy help understand and clarify the structure of the films and the doping mechanism. F4TCNQ? anions are incorporated into the layers of side chains and orient with their long molecular axis perpendicular to the polymer chains. The ordering of dopant molecules depends closely on the length and packing of the alkyl side chains. Increasing the dopant concentration results in a continuous variation of unit cell parameters of the doped phase. The high orientation results in anisotropic charge conductivity (σ) and thermoelectric properties that are both enhanced in the direction of the polymer chains (σ = 22 ± 5 S cm?1 and S = 60 ± 2 µV K?1). The method of fabrication of such highly oriented conducting polymer films is versatile and is applicable to a large palette of semiconducting polymers. 相似文献
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Patterned Growth: Patterned Growth of P‐Type MoS2 Atomic Layers Using Sol–Gel as Precursor (Adv. Funct. Mater. 35/2016) 下载免费PDF全文
Wei Zheng Junhao Lin Wei Feng Kai Xiao Yunfeng Qiu XiaoShuang Chen Guangbo Liu Wenwu Cao Sokrates T. Pantelides Wu Zhou PingAn Hu 《Advanced functional materials》2016,26(35):6495-6495
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Conformation Changes: Graphene‐Oxide‐Conjugated Polymer Hybrid Materials for Calmodulin Sensing by Using FRET Strategy (Adv. Funct. Mater. 28/2015) 下载免费PDF全文
Hongbo Yuan Junjie Qi Chengfen Xing Hailong An Ruimin Niu Yong Zhan Yibing Fan Wenmin Yan Ruihua Li Bing Wang Shu Wang 《Advanced functional materials》2015,25(28):4560-4560
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Hannah L. Smith Jordan T. Dull Elena Longhi Stephen Barlow Barry P. Rand Seth R. Marder Antoine Kahn 《Advanced functional materials》2020,30(17)
n‐Doping electron‐transport layers (ETLs) increases their conductivity and improves electron injection into organic light‐emitting diodes (OLEDs). Because of the low electron affinity and large bandgaps of ETLs used in green and blue OLEDs, n‐doping has been notoriously more difficult for these materials. In this work, n‐doping of the polymer poly[(9,9‐dioctylfluorene‐2,7‐diyl)‐alt‐(benzo[2,1,3]thiadiazol‐4,7‐diyl)] (F8BT) is demonstrated via solution processing, using the air‐stable n‐dopant (pentamethylcyclopentadienyl)(1,3,5‐trimethylbenzene)ruthenium dimer [RuCp*Mes]2. Undoped and doped F8BT films are characterized using ultraviolet and inverse photoelectron spectroscopy. The ionization energy and electron affinity of the undoped F8BT are found to be 5.8 and 2.8 eV, respectively. Upon doping F8BT with [RuCp*Mes]2, the Fermi level shifts to within 0.25 eV of the F8BT lowest unoccupied molecular orbital, which is indicative of n‐doping. Conductivity measurements reveal a four orders of magnitude increase in the conductivity upon doping and irradiation with ultraviolet light. The [RuCp*Mes]2‐doped F8BT films are incorporated as an ETL into phosphorescent green OLEDs, and the luminance is improved by three orders of magnitude when compared to identical devices with an undoped F8BT ETL. 相似文献