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活性溅射沉积的氧化氮薄膜:氧气流速效应

Published: September 28, 2019
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Özet

在这里,我们提出了一个协议,通过反应溅射以不同的氧气流速沉积氧化氮薄膜,作为在perovskite太阳能电池中的电子传输层。

Abstract

反应溅射是一种多功能技术,用于形成具有极佳均匀性的紧凑型薄膜。此外,它还便于控制沉积参数,如气体流速,从而改变成分,从而改变薄膜所需的特性。在本报告中,反应溅射用于沉积氧化氮薄膜。镍靶作为金属源,不同的氧气流速沉积氧化氮薄膜。氧气流量从3sccm变为10 sccm。沉积在低氧流速率下的薄膜具有较高的导电性,当用作电子传输层时,可提供更好的超氧化物太阳能电池。

Introduction

溅射技术被广泛用于沉积高质量的薄膜。其主要应用在半导体行业,虽然它也用于表面涂层,以改善机械性能,和反射层1。溅射的主要优点是有可能将不同的材料沉积在不同的基材上;良好的可重复性和对沉积参数的控制。溅射技术允许均匀薄膜沉积,与化学气相沉积 (CVD)、分子束外延 (MBE) 和原子层沉积 (ALD) 等其他沉积方法相比,在大面积且成本低。12.通常,由溅射沉积的半导体薄膜是无定形或多晶的,然而,有一些关于溅射3、4的外延生长的报告。然而,溅射过程非常复杂,参数范围宽5,因此,为了实现高质量的薄膜,必须对每种材料的过程和参数优化有良好的理解。

有几篇文章报道了氧化氮薄膜通过溅射沉积,以及氮化物6和碳化铀7。在Nb氧化物中,五氧化二氮(Nb2O5)是一种透明、空气稳定、水溶性的材料,具有广泛的多态性。它是一种 n 型半导体,带隙值范围从 3.1 到 5.3 eV,使这些氧化物具有广泛的应用范围8、9、10、11、12、13 1415,16,17,18,19。Nb2O5作为一种有前途的材料,因其具有可比的电子注入效率和与二氧化钛 (TiO2)相比的化学稳定性,因此备受关注。此外,Nb2O5的带隙可以改善14单元的开路电压(Voc)。

在这项工作中,Nb2O5在不同的氧气流速下通过反应溅射沉积。在低氧流率下,薄膜的电导率增加,而不使用掺杂物,从而在系统内引入杂质。这些薄膜被用作在perovskite太阳能电池中的电子传输层,提高这些电池的性能。结果发现,减少氧气量会导致氧空位的形成,从而增加薄膜的导电性,使太阳能电池具有更高的效率。

Protocol

1. 蚀刻和清洁基板 使用玻璃切割系统,形成 2.5 x 2.5 厘米的氟化物薄氧化物 (FTO) 基板。 用热胶带保护基板表面的一部分,使一侧露出 0.5 厘米。 将少量锌粉(足以覆盖待蚀区域)沉积在暴露的 FTO 顶部,并缓慢地将浓缩盐酸 (HCl) 滴在锌粉上,直到所有锌粉被反应消耗。紧接着,用去离子 (DI) 水冲洗基板。注意:大量氢气是由锌和HCl反应产生的。 取出胶?…

Representative Results

在溅射系统中,沉积速率受氧流速的影响很大。当氧气流量增加时,沉积速率降低。考虑到所用目标区域的现状和等离子体功率,从3至4sccm的沉积速率有表达性下降,然而,当氧气从4个增加到10sccm时,它变得不那么明显。在3 sccm的体制中,沉积速率为1.1 nm/s,在10 sccm中突然减小到0.1纳米/s,如图1所示。 形成的氧化氮相取决于氧气流速。对于小于3 sccm 的…

Discussion

在这项工作中制备的氧化氮薄膜被用作在perovskite太阳能电池中的电子传输层。电子传输层最重要的特征是防止重组、堵塞孔和有效地传输电子。

在这方面,使用反应溅射技术是有利的,因为它产生密集和紧凑的薄膜。此外,如前所述,与溶胶、阳极氧化、热液和化学气相沉积合成方法14、21、22相比,活性溅射是最适合沉积大面积<s…

Açıklamalar

The authors have nothing to disclose.

Acknowledgements

这项工作得到了圣保罗埃斯塔多·埃斯奎萨基金会的支持,《圣保罗中心》(CDMF-FAPESP No 2013/07296-2, 2017/11072-3,2013/09963-6 和 2017/18916-2)。特别感谢Máximo Siu Li教授的PL测量。

Materials

2-propanol Merck 67-63-0 solvent with maximum of 0.005% H2O
4-tert-butylpyridine Sigma Aldrich 3978-81-2 chemical with 96% purity
acetonitrile Sigma Aldrich 75-05-8 anhydrous solvent , 99.8% purity
bis(trifluoromethane)sulfonimide lithium salt Sigma Aldrich 90076-65-6 chemical with ≥99.95% purity
chlorobenzene Sigma Aldrich 108-90-7 anhydrous solvent , 99.8% purity
ethanol Sigma Aldrich 200-578-6 solvent
Fluorine doped tin oxide (SnO2:F) glass substrate Solaronix TCO22-7/LI substrate to deposit films
Kaptom tape Usinainfo 04227 thermal tape used to cover the substrates
Kurt J Lesker magnetron sputtering system Kurt J Lesker —— Sputtering equipment used to deposit compact films
Lead (II) iodide Alfa Aesar 10101-63-0 PbI2 salt- 99.998% purity
methylammonium iodide Dyesol 14965-49-2 CH3NH3I salt
N2,N2,N2′,N2′,N7,N7,N7′,N7′-octakis (4-methoxyphenyl)-9,9′-spirobi [9H-fluorene]-2,2′,7,7′-tetramine Sigma Aldrich 207739-72-8 Spiro-OMeTAD salt, 99% purity
Niobium target of 3” CBMM- Brazilian Metallurgy and Mining Company —— niobium sputtering target used in the sputtering system
N-N dimethylformamide Merck 68-12-2 solvent with maximum of 0.003% H2O
TiO2 paste Dyesol DSL 30NR-D titanium dioxide paste
tris(2-(1H-pyrazol-1-yl)-4-tert-butylpyridine)cobalt(III) tri[bis(trifluoromethane)sulfonimide] Dyesol 329768935 FK 209 Co(III) TFSL salt

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Fernandes, S. L., Affonço, L. J., Junior, R. A. R., da Silva, J. H. D., Longo, E., Graeff, C. F. d. O. Niobium Oxide Films Deposited by Reactive Sputtering: Effect of Oxygen Flow Rate. J. Vis. Exp. (151), e59929, doi:10.3791/59929 (2019).

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