磷酸处理对多孔SiO<sub>2</sub>薄膜质子导电特性和双电层薄膜晶体管性能的影响

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万相, 刘阳辉, 张洪亮. 磷酸处理对多孔SiO₂薄膜质子导电特性和双电层薄膜晶体管性能的影响 . 无机材料学报, 2014, 29(5): 482-486
WAN Xiang, LIU Yang-Hui, ZHANG Hong-Liang. Effects of H₃PO₄ Treated Porous SiO₂ on Proton Conductivity and Performances of EDL-TFTs . Journal of Inorganic Materials, 2014, 29(5): 482-486 复制到剪切板

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磷酸处理对多孔SiO₂薄膜质子导电特性和双电层薄膜晶体管性能的影响

万相^1,², 刘阳辉¹, 张洪亮¹

1. 中国科学院宁波材料技术与工程研究所, 宁波 315201

2. 中国科学技术大学纳米科学技术学院, 苏州215123

通讯作者：张洪亮, 博士. E-mail:zhanghl@nimte.ac.cn

作者简介：万相(1989-), 男, 硕士研究生. E-mail:wanxiang@nimte.ac.cn

基金:国家自然科学基金(51302276, 51102187);浙江省博士后择优项目(BSH1302050);

摘要

采用等离子体增强化学气相沉积法(PECVD)制备了多孔SiO₂薄膜, 系统地研究了不同浓度磷酸处理对多孔SiO₂薄膜的质子导电特性、双电层电容和以此多孔SiO₂薄膜为栅介质的铟锌氧(IZO)双电层薄膜晶体管性能的影响。结果表明: 多孔SiO₂薄膜的质子电导率和双电层电容随磷酸浓度升高而增大, 60%浓度磷酸处理后多孔SiO₂薄膜质子电导率和双电层电容分别达到1.51×10^-4S/cm和6.33 μF/cm²。随磷酸浓度升高, 双电层薄膜晶体管的工作电压降低, 并且, 电流开关比也变大。其中60%浓度磷酸处理后器件工作电压为1.2 V, 迁移率为20 cm²/(V·s), 电流开关比为4×10⁶。这种双电层薄膜晶体管有望应用在化学和生物传感等领域。

关键词: 双电层; 薄膜晶体管; 磷酸处理; 多孔SiO₂

中图分类号:TN321 文献标志码:A 文章编号:1000-324X(2014)05-0482-05

Effects of H₃PO₄ Treated Porous SiO₂ on Proton Conductivity and Performances of EDL-TFTs

WAN Xiang^1,², LIU Yang-Hui¹, ZHANG Hong-Liang¹

1. Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China

2. Nano Science and Technology, University of Science and Technology of China, Suzhou 215123, China

Fund:National Natural Science Foundation of China (51302276, 51102187); Postdoctoral Research Preferred Funds (BSH1302050);

Abstract

Porous SiO₂ films were deposited by plasma enhanced chemical vapor deposition and were treated by H₃PO₄ solution with various concentrations. Then indium-zinc-oxide (IZO) electric-double-layer thin-film transistors (EDL- TFTs) were fabricated by using such porous SiO₂ films as the gate dielectrics. The effects of H₃PO₄ treatments on the proton conductivity and EDL capacitance of porous SiO₂ films and on the performances of EDL-TFTs were investigated systematically. The proton conductivity and EDL capacitance of SiO₂ films increase with the H₃PO₄ concentration increase. A high proton conductivity of 1.51×10^-4S/cm and a large EDL capacitance of 6.33 μF/cm² are obtained for porous SiO₂ films which were treated with 60% H₃PO₄ solution. The operating voltage decreases and the on/off ratio increases with the increasing H₃PO₄ concentration. The EDL-TFTs gated by porous SiO₂ films treated with 60% H₃PO₄ solution show the best performance with a low operating voltage of 1.2 V, a high mobility of 20 cm²/(V·s), and a large on/off ratio of 4×10⁶. Such EDL-TFTs are promising for biosensors and chemical sensors in the future.

Keyword: electric-double-layer; thin-film-transistors; H3PO4 treatment; porous SiO₂

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引言

具有质子导电特性的电解质已经被广泛应用于低压、低功耗的薄膜晶体管(TFTs)领域的栅介质材料中^{[ 1, 2]}。相比传统高k栅介质材料, 具有质子导电特性的电解质展现了大电容的特性, 这主要归结于电解质中质子可以在电场驱动下和TFTs沟道电子相互耦合形成大的双电层(EDL)电容^{[ 3]}, 这种EDL电容大大降低TFTs的工作电压。Panzer等^{[ 4, 5]}报道了一种有机聚合物质子导体为栅介质的有机薄膜晶体管(OTFTs), EDL电容高达5 μF/cm², 器件的工作电压低于2 V。这类以有机质子导体为栅介质的双电层有机薄膜晶体管(EDL-OTFTs)在低压、低功耗方面取得了较大进展^{[ 6, 7]}。近年来, 基于质子在多孔材料的纳米孔道中高效的电输运行为^{[ 8]}, 研究人员尝试用多孔无机质子导体取代有机质子导体获得EDL电容^{[ 9, 10]}。Lu等^{[ 11]}报道了PECVD法制备的多孔SiO₂作为栅介质EDL-TFTs, 其EDL电容为2.14 μF/cm², 工作电压为1.5 V。

提高质子导体的质子导电性对于获得高电学性能的EDL-TFTs具有重要意义。在质子交换膜(PEMs)等领域中, 磷酸基团(-PO₃H₂)由于其强酸性以及高介电常数等特点, 被广泛用于提高多孔薄膜的质子导电性^{[ 12, 13]}。但有关采用磷酸溶液处理对多孔SiO₂膜的质子导电特性、EDL电容及EDL-TFTs电学特性影响的研究尚未见报道。本研究采用不同浓度的磷酸对PECVD法制备的多孔SiO₂薄膜作浸泡处理, 探讨了磷酸浓度对多孔SiO₂质子导电特性、EDL电容及EDL-TFTs电学特性的影响, 以期为化学和生物传感器提供有力依据和器件基础。

1 实验方法

图1(a)是多孔SiO₂薄膜为栅介质, IZO为源漏极和沟道的具有底栅结构的EDL-TFTs示意图。器件制备过程如下: 首先, 在室温条件下, 用PECVD法在ITO导电玻璃表面沉积SiO₂薄膜。反应气体为SiH₄和O₂, 流量比为3:18, 反应过程中腔体气压控制在30 Pa, 射频功率为100 W, 沉积时间为30 min。然后, 将部分制备样品分别用体积分数为20%、40%和60%的磷酸溶液浸泡24 h后烘干。接下来, 用IZO靶材以磁控溅射方法在磷酸处理和未经处理的SiO₂薄膜表面制备源极和漏极。由于磁控溅射的IZO粒子具有很高的动能, 能够绕射进入掩膜板和SiO₂薄膜表面的间隙之中, 在源漏电极形成的同时, 沟道层也在间隙里自组装形成^{[ 14]}, 如图所示。磁控溅射的反应气体为Ar, 气压控制在0.5 Pa, 射频功率为100 W, 溅射时间为15 min。所有制备过程都在室温下完成。

采用场发射扫面电镜和透射电镜表征SiO₂薄膜的截面形貌, 测试样品分别为硅片和铜片衬底上以同等实验条件生长的SiO₂薄膜。用Solartron 1260阻抗分析仪测试SiO₂薄膜的质子导电特性和电容特性, 并用Keithley 4200半导体参数仪测试TFTs器件的电学性能, 测量条件均为常温、暗室、45%相对湿度。

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	图1 EDLC-TFTs的器件结构示意图(a)及SiO₂薄膜截面的扫描电镜(b)和透射电镜(c)照片Fig. 1 Schematic diagram of vertical EDL-TFTs (a) and cross-sectional SEM image (b) and TEM image (c) of the as-deposited SiO₂

2 结果与讨论

2.1 PECVD方法制备的SiO₂薄膜微结构

图1(b)是硅片衬底上生长的SiO₂薄膜截面的扫描电镜照片, 可见PECVD方法生长的SiO₂薄膜是由大量柱状排列的颗粒组成, 颗粒之间存在很多孔隙。图1(c)是铜片衬底上生长的SiO₂薄膜的透射电镜照片, 可见SiO₂薄膜具有明显的纳米孔结构。经过24 h的浸泡, 磷酸溶液可以轻易渗透这种高度多孔的薄膜后并粘附于SiO₂颗粒^{[ 12]}, 使-PO₃H₂通过硅羟基连接在SiO₂颗粒表面^{[ 15]}。而且, 纳米孔道为质子提供了高效的输运通道。在TFTs栅极外加正电场的作用下, H⁺通过纳米孔道纵向漂移至栅介质/沟道界面处, 在沟道中感应大量电子, 形成了EDL, 增强了栅极和沟道之间的电容耦合(图1(a))。

2.2 磷酸浓度对SiO₂薄膜质子导电特性的影响

图2(a)为不同浓度磷酸处理和未经处理的SiO₂薄膜的Cole-Cole图。质子电导率根据

获得^{[ 16]}。其中 R为半圆与 x正半轴交点, 这里的测量结果取五个不同器件的中间值, L为SiO₂薄膜厚度, A为测量电极面积, R₀为测试回路的附加电阻。图2(b)展示了计算出的四种SiO₂薄膜的质子电导率。可以看出, 质子电导率随磷酸浓度的升高而线性上升。60%磷酸处理的SiO₂薄膜具有最高的质子电导率(1.51×10^-4S/cm), 为未经处理的1.5倍(1.04×10^-4S/cm)。磷酸处理后质子导电特性增强的原因是由于连接在SiO₂颗粒表面的-PO₃H₂相互作用形成了Grotthuss链^{[ 17, 18]}, 而H⁺可以在Grotthuss链构成的输运网络中自由跳跃, 薄膜的质子传递能力得以增强。因此, 所用磷酸浓度的升高, 增加了这种Grotthuss链的形成, 从而增强了SiO₂多孔薄膜的质子导电特性。这种质子电导率随酸性溶液浓度变化的特性, 将在pH传感器领域有很好的应用前景。

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	图2 不同浓度磷酸处理的SiO₂薄膜的Cole-Cole (a)和质子电导(b)图Fig. 2 Typical Cole-Cole plots (a) and proton conductivity (b) of SiO₂ proton conductor treated by H₃PO₄ solution with different concentrations

2.3 磷酸浓度对SiO₂薄膜EDL电容和漏电流的影响

图3(a)为SiO₂薄膜在频率为1.0 Hz~10 MHz区间内的单位面积电容。四条电容-频率曲线均呈现出典型的EDL电容特征: 由于质子-电子的耦合作用, SiO₂薄膜在低频区具有较大的EDL电容, 并随着频率的上升电容逐渐下降, 最后失去EDL效应^{[ 19]}。当频率为1 Hz时, 经过60%磷酸处理的SiO₂薄膜EDL电容为6.33 μF/cm², 比传统电容理论计算结果( )大三个数量级。图中可见60%磷酸处理的SiO₂薄膜EDL电容为未经处理(4.29 μF/cm²)的1.5倍。随着磷酸浓度升高, 电容在低频区(<1 kHz)清晰地呈现出逐渐增大的趋势, 即使在较高的频率(10 kHz), 60%磷酸处理的SiO₂薄膜仍有1.4 μF/cm²的EDL电容, 而未经处理的则低于1 μF/cm²。磷酸处理后SiO₂薄膜EDL电容的增大, 最主要原因不仅是由于质子电导率增加, 而且是由于-PO₃H₂电离产生更多的H⁺在栅电压驱动下漂移至栅介质/沟道界面处形成累积电荷, 界面电荷密度的增加导致了EDL致密的Helmholtz层的缩小, 从而导致了EDL电容的增大。这些结果与引入质子能够使得离子液在电解质/栅极和电解质/半导体的界面的EDL电容增加的结果一致^{[ 20]}。图3(b)为SiO₂薄膜在栅极偏压为-1.5 V~1.5 V区间内的漏电流曲线。从图中可以看出, 不同浓度的磷酸处理后漏电流很低, 均在2 nA以内, 远小于TFTs的工作电流。这保证了磷酸处理导致的漏电流变化对TFTs的电学性能影响甚微。

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	图3 不同浓度磷酸处理的SiO₂薄膜的电容-频率曲线(a)和漏电流曲线(b)Fig. 3 Specific capacitance vs frequency characteristics (a) and gate leakage current (b) curves of SiO₂ proton conductor treated by H₃PO₄ solution with different concentrations

2.4 磷酸处理SiO₂薄膜对EDL-TFTs电学性能的影响

图4(a)为以60%磷酸处理SiO₂为栅介质的EDL-TFTs的输出特性曲线 I_ds- V_ds。曲线随着 V_gs从-0.4 V变化到1 V的过程逐渐向电流增大的方向移动, 说明器件为典型的n型TFTs。较高的 V_ds下器件显示出了良好的电流饱和特性, 而在较低的 V_ds下器件显示出了良好的线性特性, 说明TFTs源漏极和沟道之间具有良好的欧姆接触。 V_gs=1 V和 V_ds=1.2 V下器件具有较高的饱和电流(~1.4 mA), 器件工作电压为1.2 V。图4(b)展示了器件的转移特性曲线, 测量过程中源漏电压 V_ds控制在1.2 V。如图所示, 60%磷酸处理SiO₂薄膜为栅介质的TFTs在栅压为1.2 V达到源漏电流最大值0.75 mA, 此时TFTs处于完全开启状态。而在栅压为-0.45 V, 源漏电压为最小值0.18 nA, 此时n型沟道完全耗尽。△ V_gs仅为1.65 V, 开关比高达4×10⁶, 这归功于60% 磷酸处理SiO₂薄膜极高的EDL电容(取6.33 μF/cm²)。阈值电压由 I_ds^1/2- V_gs线性区切线与横轴的交点得出, 如图所示为0.27 V, 说明器件为增强型TFTs。饱和区( V_gs≥ V_gs- V_th)场效应迁移率由公式拟合, 结果为20 cm²/(V·s)。图4(c)为不同浓度磷酸处理SiO₂为栅介质EDL- TFTs的转移特性曲线。未经磷酸处理, 以及20%和40%磷酸处理后, 器件的工作电压分别为1.5 V、1.5 V和1.3 V。其中未经磷酸处理的SiO₂薄膜为栅介质的EDL-TFTs, △ V_gs为2.45 V, 开关比为5×10⁵。随着磷酸浓度的升高, 器件可以在更小的栅压变化范围内由关态向开态转变, 工作电压和电流开关比分别相应地降低和提高, 这是由于磷酸处理后EDL电容增大导致了栅极和沟道之间耦合增强, 使得栅极电压能感应更多的沟道电子, 从而降低了工作电压, 提高了电流开关比。特别地, 据Guo等^{[ 21]}报道, 环境湿度对EDL电容和EDL-TFT的电学特性影响很大。因此, 样品测试环境的相对湿度始终维持在45%。

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图4 以60%磷酸处理的SiO₂薄膜为栅介质的EDL-TFTs的输出特性(a), 转移特性(b)和不同浓度磷酸处理的SiO₂薄膜为栅介质的EDL-TFTs的转移特性(c)曲线Fig. 4 Electrical characteristics of the EDL-TFTs gated by SiO₂ proton conductor treated by 60% H₃PO₄ solution(a) Output characteristics; (b) Transfer characteristics; (c) Transfer characteristics of the EDL-TFTs gated by SiO₂ proton conductor treated by H₃PO₄ solution with different concentrations

3 结论

本研究用不同浓度的磷酸溶液对PECVD法制备的多孔SiO₂薄膜进行浸泡处理, 对于磷酸处理直接影响多孔SiO₂质子导电特性, 从而作用于EDL电容及EDL-TFTs电学特性等方面进行了系统研究, 结果表明:

1) 多孔SiO₂薄膜的质子电导率随磷酸溶液浓度的升高而线性上升, 60%磷酸处理的SiO₂薄膜具有最高的质子电导率(1.51×10^-4S/cm), 为未经处理的1.5倍。

2) 多孔SiO₂薄膜的EDL电容在低频区(<1 kHz)随磷酸溶液浓度的升高而增大.频率为1 Hz时, 60%浓度磷酸处理的SiO₂薄膜具有最大的EDL电容(6.33 μF/cm²), 为未经处理的1.5倍。

3) 随着磷酸浓度的升高, EDL-TFTs的工作电压降低, 并且, 电流开关比也变大。60%浓度磷酸处理的SiO₂薄膜作为栅介质的IZO-TFTs工作电压仅为1.2 V, 场效应迁移率为20 cm²/(V·s), 电流开关比高达4×10⁶。

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[13]	ZENG J, HE B B, LAMB K, et al. Phosphoric acid functionalized pre-sintered meso-silica for high temperature proton exchange membrane fuel cells. Chem. Commun. , 2013, 49(41): 4655-4657. [本文引用:1] [JCR: 6.378]
[14]	KIM D R, LEE C H, ZHENG X L. Probing flow velocity with silicon nanowire sensors. Nano Lett. , 2009, 9(5): 1984-1988. [本文引用:1] [JCR: 13.025]
[15]	JIANG J, SUN J, LU A X, et al. Self-assembled ultralow-voltage flexible transparent thin-film transistors gated by SiO₂-based solid electrolyte. IEEE Electron Dev. Lett. , 2011, 58(2): 547-552. [本文引用:1]
[16]	GRUZD A S, TROFIMCHUK E S, NIKONOROVA N I, et al. Novel polyolefin/silicon dioxide/H₃PO₄ composite membranes with spatially heterogeneous structure for phosphoric acid fuel cell. Int. J. Hydrogen Energy, 2013, 38(10): 4132-4143. [本文引用:1] [JCR: 3.548]
[17]	JIN Y, QIAO S Z, DA COSTA J C D, et al. Hydrolytically stable phosphorylated hybrid silicas for proton conduction. Adv. Funct. Mater. , 2007, 17(16): 3304-3311. [本文引用:1] [JCR: 9.765]
[18]	AGMON N. The Grothuss mechanism. Chem. Phys. Lett. , 1995, 244(5/6): 456-462. [本文引用:1] [JCR: 2.145]
[19]	VILCIAUSKAS L, TUCKERMAN M E, BESTER G, et al. The mechanism of proton conduction in phosphoric acid. Nat. Chem. , 2012, 4(6): 461-466. [本文引用:1] [JCR: 21.757]
[20]	LARSSON O, SAID E, BERGGREN M, et al. Insulator polarization mechanisms in polyelectrolyte-gated organic field-effect transistors. Adv. Funct. Mater. , 2009, 19(20): 3334-3341. [本文引用:1] [JCR: 9.765]
[21]	YUAN H T, SHIMOTANI H, TSUKAZAKI A, et al. Hydrogenation- induced surface polarity recognition and proton memory behavior at protic-ionic-liquid/oxide electric-double-layer interfaces, J. Am. Chem. Soc. , 2010, 132(19): 6672-6678. [本文引用:1] [JCR: 10.677]
[22]	GUO L Q, YANG Y Y, ZHU L Q, et al. Effects of humidity on performance of electric-double-layer oxide-based thin-film transistors gated by nanogranular SiO₂ solid electrolyte. AIP Advances, 2013, 3(7): 072110-1-9. [本文引用:1] [JCR: 1.349]

2007

1.067

0.0

Japanese Journal of Applied Physics. 2007, 46(6R):3613-null

Electric Double Layer Transistor of Organic Semiconductor Crystals in a Four-Probe Configuration

Hidekazu Shimotani 1,2 , Haruhiko Asanuma 1 and Yoshihiro Iwasa 1,2

<p><sup>1</sup>Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan<br/><sup>2</sup>Japan Science and Technology Agency (CREST), 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan<br/></p>

Electric double layer field-effect transistors (EDL-FETs) of rubrene single crystals using a liquid polymer electrolyte were studied in a four-probe configuration. The channel sheet resistance and the contact resistance normalized by the contact width were 0.24 MΩ and 0.83 kΩ cm in the ON-state, respectively. These values are smaller than those of previously reported conventional rubrene crystal FETs, corroborating the high carrier density accumulation in the EDL-FET. In addition, peculiar peak behaviour in the transfer characteristics did not appear in the gate voltage dependence of four-probe conductivity. This observation leads us to conclude that the peak is ascribed to the increase of the contact resistance in the high gate voltage region.

... 引言具有质子导电特性的电解质已经被广泛应用于低压、低功耗的薄膜晶体管(TFTs)领域的栅介质材料中^[1,2] ...

2008

35.749

0.0

Nature Materials. 2008, 7(11):900-906

Printable ion-gel gate dielectrics for low-voltage polymer thin-film transistors|[nbsp]|on|[nbsp]|plastic

An important strategy for realizing flexible electronics is to use solution-processable materials that can be directly printed and integrated into high-performance electronic components on plastic. Although examples of functional inks based on metallic, semiconducting and insulating materials have been developed, enhanced printability and performance is still a challenge. Printable high-capacitance dielectrics that serve as gate insulators in organic thin-film transistors are a particular priority. Solid polymer electrolytes (a salt dissolved in a polymer matrix) have been investigated for this purpose, but they suffer from slow polarization response, limiting transistor speed to less than 100 Hz. Here, we demonstrate that an emerging class of polymer electrolytes known as ion gels can serve as printable, high-capacitance gate insulators in organic thin-film transistors. The specific capacitance exceeds that of conventional ceramic or polymeric gate dielectrics, enabling transistor operation at low voltages with kilohertz switching frequencies.

... 引言具有质子导电特性的电解质已经被广泛应用于低压、低功耗的薄膜晶体管(TFTs)领域的栅介质材料中^[1,2] ...

2007

14.829

0.0

Advanced Materials. 2007, 19(1):97-101

Low-Voltage Polymer Field-Effect Transistors Gated via a Proton Conductor

L. Herlogsson 1 ,X. Crispin 1 ,N. D. Robinson 1 ,M. Sandberg 2 ,O.-J. Hagel 2 ,G. Gustafsson 3 andM. Berggren 1

<sup>1</sup>ITN, Linköpings Universitet, Campus Norrköping, SE-601 74 Norrköping, Sweden<br/><sup>2</sup>Thin Film Electronics AB, Westmansgatan 27, SE-582 16 Linköping, Sweden<br/><sup>3</sup>Acreo AB, Bredgatan 34, SE-602 21 Norrköping, Sweden<br/>

... 相比传统高k栅介质材料, 具有质子导电特性的电解质展现了大电容的特性, 这主要归结于电解质中质子可以在电场驱动下和TFTs沟道电子相互耦合形成大的双电层(EDL)电容^[3], 这种EDL电容大大降低TFTs的工作电压 ...

2005

3.794

0.0

... Panzer等^[4,5]报道了一种有机聚合物质子导体为栅介质的有机薄膜晶体管(OTFTs), EDL电容高达5 #cod#x003bc ...

0.0

... Panzer等^[4,5]报道了一种有机聚合物质子导体为栅介质的有机薄膜晶体管(OTFTs), EDL电容高达5 #cod#x003bc ...

2005

10.677

0.0

J. Am. Chem. Soc.. 2005, 127(19):6960–6961-null

Polymer Electrolyte Gate Dielectric Reveals Finite Windows of High Conductivity in Organic Thin Film Transistors at High Charge Carrier Densities

Matthew J. Panzer and C. Daniel Frisbie *

<div>Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Avenue SE, Minneapolis, Minnesota 55455</div><div></div>

Finite regions of high conductivity were observed in both n- and p-channel organic thin film transistors based on polycrystalline organic semiconductor films and a solution-processed, solid polymer electrolyte gate dielectric. The transition from a highly conductive state to a more insulating state with increasing gate bias may be attributed to the realization of carrier densities greater than 10¹⁴ charges/cm² in the semiconductor film.

... 这类以有机质子导体为栅介质的双电层有机薄膜晶体管(EDL-OTFTs)在低压、低功耗方面取得了较大进展^[6,7] ...

2006

3.794

0.0

... 这类以有机质子导体为栅介质的双电层有机薄膜晶体管(EDL-OTFTs)在低压、低功耗方面取得了较大进展^[6,7] ...

2008

14.829

0.0

Advanced Materials. 2008, 20(4):686-690

High-Capacitance Ion Gel Gate Dielectrics with Faster Polarization Response Times for Organic Thin Film Transistors

J. H. Cho 1 ,J. Lee 1 ,Y. He 2 ,B. S. Kim 1 ,T. P. Lodge 2 andC. D. Frisbie 1

<sup>1</sup>Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Ave. SE, Minneapolis, MN 55455 (USA)<br/><sup>2</sup>Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, MN 55455 (USA)<br/>

... 近年来, 基于质子在多孔材料的纳米孔道中高效的电输运行为^[8], 研究人员尝试用多孔无机质子导体取代有机质子导体获得EDL电容^[9,10] ...

2010

21.757

0.0

Nature Chemistry. 2010, 2(6):503-508

Enhancement of anhydrous proton transport by supramolecular nanochannels in comb polymers

Transporting protons is essential in several biological processes as well as in renewable energy devices, such as fuel cells. Although biological systems exhibit precise supramolecular organization of chemical functionalities on the nanoscale to effect highly efficient proton conduction, to achieve similar organization in artificial systems remains a daunting challenge. Here, we are concerned with transporting protons on a micron scale under anhydrous conditions, that is proton transfer unassisted by any solvent, especially water. We report that proton-conducting systems derived from facially amphiphilic polymers that exhibit organized supramolecular assemblies show a dramatic enhancement in anhydrous conductivity relative to analogous materials that lack the capacity for self-organization. We describe the design, synthesis and characterization of these macromolecules, and suggest that nanoscale organization of proton-conducting functionalities is a key consideration in obtaining efficient anhydrous proton transport.

... 近年来, 基于质子在多孔材料的纳米孔道中高效的电输运行为^[8], 研究人员尝试用多孔无机质子导体取代有机质子导体获得EDL电容^[9,10] ...

2011

14.829

0.0

Advanced Materials. 2011, 23(45):5383-5386

Tungsten Oxide as a Gate Dielectric for Highly Transparent and Temperature-Stable Zinc-Oxide-Based Thin-Film Transistors

Michael Lorenz * ,Holger von Wenckstern andMarius Grundmann

Institut für Experimentelle Physik II, Halbleiterphysik, Universität Leipzig, Linnéstrasse 5, 04103 Leipzig, Germany<br/><sup>*</sup>Institut für Experimentelle Physik II, Halbleiterphysik, Universität Leipzig, Linnéstrasse 5, 04103 Leipzig, Germany.

... 近年来, 基于质子在多孔材料的纳米孔道中高效的电输运行为^[8], 研究人员尝试用多孔无机质子导体取代有机质子导体获得EDL电容^[9,10] ...

2013

0.0

... Lu等^[11]报道了PECVD法制备的多孔SiO₂作为栅介质EDL-TFTs, 其EDL电容为2 ...

2009

3.794

0.0

... 在质子交换膜(PEMs)等领域中, 磷酸基团(-PO₃H₂)由于其强酸性以及高介电常数等特点, 被广泛用于提高多孔薄膜的质子导电性^[12,13] ...

... 经过24 h的浸泡, 磷酸溶液可以轻易渗透这种高度多孔的薄膜后并粘附于SiO₂颗粒^[12], 使-PO₃H₂通过硅羟基连接在SiO₂颗粒表面^[15] ...

2013

6.378

0.0

... 在质子交换膜(PEMs)等领域中, 磷酸基团(-PO₃H₂)由于其强酸性以及高介电常数等特点, 被广泛用于提高多孔薄膜的质子导电性^[12,13] ...

2009

13.025

0.0

Nano Lett.. 2009, 9(5):1984–1988-null

Probing Flow Velocity with Silicon Nanowire Sensors

Dong Rip Kim , Chi Hwan Lee and Xiaolin Zheng *

<div>Department of Mechanical Engineering, Stanford University, California 94305</div><div>* Corresponding author. E-mail: <a href="mailto:xlzheng@stanford.edu">xlzheng@stanford.edu</a>.</div>

We report our experimental efforts to quantify the impact of fluidic and ionic transport on the conductance level of silicon nanowire (SiNW) sensors configured as field effect transistors (FETs). Specifically, the conductance of SiNW FETs placed in a microfluidic channel was observed to change linearly with the flow velocity of electrolytic solutions. The direction of conductance change depends on the doping type of the SiNWs and their location inside the microfluidic channel, and the magnitude of the conductance change varies with the ionic strength and compositions of the electrolytic solution. Our quantitative analysis suggests that the flow velocity sensing is a consequence of the streaming potential that is generated by the movement of counterions inside the electrical double layer (EDL) of the silica substrate. The streaming potential, which varies with the flow velocity and the ionic properties of the electrolytic solution, acts in the same way as the charged analytes in affecting the conductance of SiNWs by changing the surface potential. This study highlights the importance of considering the ionic transport in analyzing and optimizing nanowire FET sensors, which can significantly change the conductance of NWs. Moreover, SiNWs were demonstrated for the first time to be able to detect the streaming potential, the flow velocity and the ionic strength, opening up their new application potentials in microfluidics.

... 由于磁控溅射的IZO粒子具有很高的动能, 能够绕射进入掩膜板和SiO₂薄膜表面的间隙之中, 在源漏电极形成的同时, 沟道层也在间隙里自组装形成^[14], 如图所示 ...

2011

0.0

... 经过24 h的浸泡, 磷酸溶液可以轻易渗透这种高度多孔的薄膜后并粘附于SiO₂颗粒^[12], 使-PO₃H₂通过硅羟基连接在SiO₂颗粒表面^[15] ...

2013

3.548

0.0

Int. J. Hydrogen Energy. 2013, 38(10):null-null

Novel polyolefin/silicon dioxide/H₃PO₄ composite membranes with spatially heterogeneous structure for phosphoric acid fuel cell

... 获得^[16] ...

2007

9.765

0.0

Advanced Functional Materials. 2007, 17(16):3304-3311

Hydrolytically Stable Phosphorylated Hybrid Silicas for Proton Conduction

Y. G. Jin 1 ,S. Z. Qiao 1 ,J. C. D. da Costa 1 ,B. J. Wood 2 ,B. P. Ladewig 1 andG. Q. Lu 1

<sup>1</sup>ARC Centre of Excellence for Functional Nanomaterials, Australian Institute of Bioengineering and Nanotechology, The University of Queensland, QLD 4072 (Australia)<br/><sup>2</sup>Brisbane Surface Analysis Facility, The University of Queensland, QLD 4072 (Australia)<br/>

A new approach to the synthesis of fully immobilized phosphorus functionalized hybrid proton conductive gels based on phosphonic acid grafting is presented in this paper. The hybrid silicas with different amounts of phosphonic acid have been prepared and characterized using Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, Brunauer–Emmett–Teller surface area analysis, thermogravimetric analysis, and electrochemical techniques. The proton conductivity of the materials depend strongly on hydration, which increases by four orders of magnitude over the relative humidity (RH) range of 20 to 100 %, up to a maximum of 0.027 S cm^–1 at 100 °C and 100 % RH. For the reported samples, proton conduction is believed to occur within a dynamic hydrogen-bond network formed by functionalized P–OH groups and water molecules by the Grotthuss mechanism. However, the proton conductive sites (P–OH) are likely to be partially immobilized by strong protonic receptors (N atoms in amines), which reduces the free P–OH groups and restricts proton transfer. Hydration may cause a bonding structural rearrangement, which results in more free P–OH groups as active proton conductive sites and, therefore, greatly increased proton conductivity is observed.

... 磷酸处理后质子导电特性增强的原因是由于连接在SiO₂颗粒表面的-PO₃H₂相互作用形成了Grotthuss链^[17,18], 而H⁺可以在Grotthuss链构成的输运网络中自由跳跃, 薄膜的质子传递能力得以增强 ...

1995

2.145

0.0

Chem. Phys. Lett.. 1995, 244(5/6):null-null

The Grothuss mechanism

2012

21.757

0.0

Nature Chemistry. 2012, 4(6):461-466

The mechanism of proton conduction in phosphoric acid

Neat liquid phosphoric acid (H₃PO₄) has the highest intrinsic proton conductivity of any known substance and is a useful model for understanding proton transport in other phosphate-based systems in biology and clean energy technologies. Here, we present an ab initio molecular dynamics study that reveals, for the first time, the microscopic mechanism of this high proton conductivity. Anomalously fast proton transport in hydrogen-bonded systems involves a structural diffusion mechanism in which intramolecular proton transfer is driven by specific hydrogen bond rearrangements in the surrounding environment. Aqueous media transport excess charge defects through local hydrogen bond rearrangements that drive individual proton transfer reactions. In contrast, strong, polarizable hydrogen bonds in phosphoric acid produce coupled proton motion and a pronounced protic dielectric response of the medium, leading to the formation of extended, polarized hydrogen-bonded chains. The interplay between these chains and a frustrated hydrogen-bond network gives rise to the high proton conductivity.

... 四条电容-频率曲线均呈现出典型的EDL电容特征: 由于质子-电子的耦合作用, SiO₂薄膜在低频区具有较大的EDL电容, 并随着频率的上升电容逐渐下降, 最后失去EDL效应^[19] ...

2009

9.765

0.0

Advanced Functional Materials. 2009, 19(20):3334-3341

Insulator Polarization Mechanisms in Polyelectrolyte-Gated Organic Field-Effect Transistors

Oscar Larsson,Elias Said,Magnus Berggren andXavier Crispin *

Linköping University Department of Science and Technology, Organic Electronics SE-601 74 Norrköping (Sweden)<br/><sup>*</sup>Linköping University Department of Science and Technology, Organic Electronics SE-601 74 Norrköping (Sweden)

Electrolyte-gated organic field-effect transistors (OFETs) hold promise for robust printed electronics operating at low voltages. The polarization mechanism of thin solid electrolyte films, the gate insulator in such OFETs, is still unclear and appears to limit the transient current characteristics of the transistors. Here, the polarization response of a thin proton membrane, a poly(styrenesulfonic acid) film, is controlled by varying the relative humidity. The formation of the conducting transistor channel follows the polarization of the polyelectrolyte, such that the drain transient current characteristics versus the time are rationalized by three different polarization mechanisms: the dipolar relaxation at high frequencies, the ionic relaxation (migration) at intermediate frequencies, and the electric double-layer formation at the polyelectrolyte interfaces at low frequencies. The electric double layers of polyelectrolyte capacitors are formed in ∼1 µs at humid conditions and an effective capacitance per area of 10 µF cm⁻² is obtained at 1 MHz, thus suggesting that this class of OFETs might operate at up to 1 MHz at 1 V.

... 这些结果与引入质子能够使得离子液在电解质/栅极和电解质/半导体的界面的EDL电容增加的结果一致^[20] ...

2010

10.677

0.0

J. Am. Chem. Soc.. 2010, 132(19):6672–6678-null

Hydrogenation-Induced Surface Polarity Recognition and Proton Memory Behavior at Protic-Ionic-Liquid/Oxide Electric-Double-Layer Interfaces

Hongtao Yuan * † ‡ , Hidekazu Shimotani † ‡ , Atsushi Tsukazaki † , Akira Ohtomo † , Masashi Kawasaki † ‡ $ and Yoshihiro Iwasa * † ‡

<div>Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan, Japan Science and Technology Agency (CREST), Kawaguchi 332-0012, Japan, and WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577 Japan</div><div><a href="mailto:htyuan@imr.tohoku.ac.jp">htyuan@imr.tohoku.ac.jp</a>; <a href="mailto:iwasa@imr.tohoku.ac.jp">iwasa@imr.tohoku.ac.jp</a>,† <p class="last">IMR. Tohoku University.</p>,‡ <p class="last">CREST, JST.</p>,$ <p class="last">WPI-AIMR, Tohoku University.</p></div>

The electric-double-layer (EDL) formed at liquid/solid interfaces provides a broad and interdisciplinary attraction in terms of electrochemistry, photochemistry, catalysts, energy storage, and electronics. Especially in recent years, much effort has been devoted to the fundamental understanding and practical applications of transistor configurations with EDLs because of their ability for high-density charge accumulation. However, to exploit additional new functionalities of such an emerging interface is not only of great importance but also a huge challenge. Here, we demonstrate that, by introducing protic ionic liquid (PIL) as the gate dielectric for ZnO EDL transistors (EDLTs), small and chemically active ions, such as protons and hydroxyls, can serve as an adsorption medium to extend the interfacial functionalities of EDLTs. By selectively driving the H⁺ or OH⁻ groups onto ZnO channel surfaces with an electric field, the charged adsorbates interact with surface atoms in different adsorption mechanisms, showing remarkable variations in electron transport and providing a possibility for the recognition of surface polarity. Most significantly, the large hysteresis in the transfer characteristics of PIL−EDLTs makes the device available and promising for nonvolatile proton memory devices via surface hydrogenation and dehydrogenation processes. Such a finding provides us with new opportunities to understand liquid/solid heterogeneous interface phenomena and to extend the practical functions of EDLs through controllable interfacial interaction.

... 特别地, 据Guo等^[21]报道, 环境湿度对EDL电容和EDL-TFT的电学特性影响很大 ...

2013

1.349

0.0