- 건국대학교

	Prof. Man-Jong Lee presented a novel paradigm for highly efficient perovskite solar cells
	관리자		492		2018.10.04

Journal published in the top SCI journal of ACS Energy Letters (Impact Factor: 12.277) <img width="444" height="305" style="margin-left: auto; display: block; margin-right: auto;" alt="" src="ArticleFile.do?id=11744668" />
Professor Man-Jong Lee (Department of Chemistry, Konkuk University) developed a novel device architecture for perovskite solar cells (PSCs) showing worldwide attention in the field of new and renewable energy and reported these results in the one of the top journal, ACS Energy Letters (Impact Factor: 12.277) on Sep. 17, 2018. The title of this article is ‘Highly Efficient Amorphous Zn2SnO4 Electron-Selective Layers Yielding over 20% Efficiency in FAMAPbI3-Based Planar Solar Cells’ (<a href="https://pubs.acs.org/doi/10.1021/acsenergylett.8b01501">https://pubs.acs.org/doi/10.1021/acsenergylett.8b01501</a>). 
Solar cells are current/voltage generating electronic devices that convert sunlight illumination into electricity. Currently, solar cells using silicon (Si) are being commercialized. Efforts to develop solar cells that are more efficient, lighter, and less costly have been concentrated worldwide. Among them, PSC is recognized as one of the top ten advances in science worldwide and is considered as a powerful candidate for the next generation solar cells through extensive worldwide researches. Since 2016, the power conversion efficiencies (PCEs) of PSCs have been enhanced up to more than 20% and the possibilities for commercial applications have been proven. 
Conventional devices commonly used n-type semiconducting TiO2 films as electron selective layers (ESL). The limitations of TiO2 films, however, hindered a breakthrough of PCE and stability of PSCs. The search for novel oxide semiconductor thin film materials has been actively conducted since 2017 and many improvements in PCE have been reported. For the first time, Prof. Lee’s team applied amorphous semiconducting Zn2SnO4 films as ESLs and reported PCEs of >20% using a novel device architecture (Fig. 1). In addition, they analyzed the behind mechanism for enhanced PCE and clarified working principles.
<img width="531" height="248" style="margin-left: auto; display: block; margin-right: auto;" alt="" src="ArticleFile.do?id=11744670" /> 
The significance of this study is as follows: 1) the amorphous semiconductor thin films (Fig. 2) are applied to the ESLs of PSCs for the first time, 2) the amorphization of Zn2SnO4 thin films show the superior uniformity of film thickness and the enhanced conductivities compared with the counterpart of crystalline material (TiO2), (3) the excellent characteristics (Figs. 5 and 6) have been experimentally achieved using the simple planar type of PSC architecture (Figs. 3 and 4), and (4) the principles have been uniquely clarified using novel characterization techniques.
<img width="640" height="328" style="margin-left: auto; display: block; margin-right: auto;" alt="" src="ArticleFile.do?id=11744671" /> <img width="562" height="264" style="margin-left: auto; display: block; margin-right: auto;" alt="" src="ArticleFile.do?id=11744672" />
This study is remarkable in that they present a new research paradigm for the research of perovskite solar cells because the new ESL films are easy to synthesise and show excellent reproducibility. Prof. Lee mentioned that “As amorphous Zn2SnO4 semiconductors are announced for the first time, various subsequent studies will be followed, and a patent protection is now ongoing”. 
This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT. This research was also supported by the Agency for Defense Development (ADD) of the Republic of Korea through the university research center program.

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