气候变化领域集成服务门户(CCPortal): How small amounts of Ge modify the formation pathways and crystallization of kesterites

CCPortal

DOI	10.1039/c7ee02318a
	How small amounts of Ge modify the formation pathways and crystallization of kesterites
	Giraldo S.; Saucedo E.; Neuschitzer M.; Oliva F.; Placidi M.; Alcobé X.; Izquierdo-Roca V.; Kim S.; Tampo H.; Shibata H.; Pérez-Rodríguez A.; Pistor P.
发表日期	2018
ISSN	17545692
起始页码	582
结束页码	593
卷号	11 期号:3
英文摘要	The inclusion of Ge into the synthesis of Cu2ZnSn(S,Se)4 absorbers for kesterite solar cells has been proven to be a very efficient way to boost the device efficiency in a couple of recent publications. This highlights the importance to elucidate the mechanisms by which Ge improves the kesterite solar cells properties to such a large extent. In this contribution, we first show how controlling the position and thickness of a very thin (10-15 nm) layer of Ge greatly influences the crystallization of kesterite thin films prepared in a sequential process. Typically, Cu2ZnSnSe4 (CZTSe) films form in a bi-layer structure with large grains in the upper region and small grains at the back. By introducing Ge nanolayers below our precursors, we observe that large CZTSe grains extending over the whole absorber thickness are formed. Additionally, we observe that Ge induces fundamental changes in the formation mechanism of the kesterite absorber. In a detailed analysis of the phase evolution with and without Ge, we combine the results of X-ray fluorescence, X-ray diffraction and Raman spectroscopy to demonstrate how the Ge influences the preferred reaction scheme during the selenization. We reveal that the presence of Ge causes a large change in the in-depth elemental distribution, induces a stabilizing Cu-Sn intermixing, and thus prevents drastic compositional fluctuations during the annealing process. This finally leads to a change from a tri-molecular towards, mainly, a bi-molecular CZTSe formation mechanism. Kesterite thin films with surprisingly large crystals of several microns in diameter can be fabricated using this approach. The results are related to the increase in device performance, where power conversion efficiencies of up to 11.8% were obtained. Finally, the consequences of the disclosed crystallization pathways and the extension to other chalcogenide technologies are discussed. © The Royal Society of Chemistry 2018.
英文关键词	Binary alloys; Crystallography; Efficiency; Selenium compounds; Solar absorbers; Solar cells; Thin films; X ray diffraction; Bi-layer structure; Compositional fluctuations; Crystallization pathway; Elemental distribution; Formation mechanism; Formation pathways; Fundamental changes; Power conversion efficiencies; Germanium; crystallization; efficiency measurement; energy efficiency; equipment; formation mechanism; fuel cell; performance assessment; Raman spectroscopy; technological development; X-ray diffraction; X-ray fluorescence
语种	英语
来源期刊	Energy & Environmental Science
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/190308
作者单位	Catalonia Institute for Energy Research (IREC), Jardins de les Dones de Negre 1, Sant Adrià de Besòs Barcelona, 08930, Spain; Centres Científics i Tecnològics de la Universitat de Barcelona (CCiTUB), Lluís Solé i Sabarís 1-3, Barcelona, 08028, Spain; Research Center for Photovoltaics, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono Tsukuba, Ibaraki, 305-8568, Japan; IN2UB, Departament d'Electrònica, Universitat de Barcelona, Martí i Franquès 1-11, Barcelona, 08028, Spain; Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany
推荐引用方式 GB/T 7714	Giraldo S.,Saucedo E.,Neuschitzer M.,et al. How small amounts of Ge modify the formation pathways and crystallization of kesterites[J],2018,11(3).
APA	Giraldo S..,Saucedo E..,Neuschitzer M..,Oliva F..,Placidi M..,...&Pistor P..(2018).How small amounts of Ge modify the formation pathways and crystallization of kesterites.Energy & Environmental Science,11(3).
MLA	Giraldo S.,et al."How small amounts of Ge modify the formation pathways and crystallization of kesterites".Energy & Environmental Science 11.3(2018).