Ji Wenbo, Zhao Yingbo, Fahad Hossain M, Bullock James, Allen Thomas, Lien Der-Hsien, De Wolf Stefaan, Javey Ali
Electrical Engineering and Computer Sciences , University of California , Berkeley , California 94720 , United States.
Materials Sciences Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States.
ACS Nano. 2019 Mar 26;13(3):3723-3729. doi: 10.1021/acsnano.9b01038. Epub 2019 Mar 7.
The reduction of carrier recombination processes by surface passivation is vital for highly efficient crystalline silicon (c-Si) solar cells and bulk wafer metrological characterization. Herein, we report a dip coating passivation of silicon surfaces in ambient air and temperature with Nafion, achieving a champion effective carrier lifetime of 12 ms on high resistivity n-type c-Si, which is comparable to state-of-the-art passivation methods. Nafion is a nonreactive polymer with strong Lewis acidity, thus leading to the formation of a large density of fixed charges at silicon surface, 1-2 orders of magnitude higher than what is achievable with conventional thin-film passivation layers. Notably, Nafion passivates the c-Si surface only by the fixed charges without chemical modification of dangling bonds, which is fundamentally different from the common practice of combining chemical with field-effect passivation. This dip coating process is simple and robust, without the need for complex equipment or parameter optimization as there is no chemical reaction involved.
通过表面钝化减少载流子复合过程对于高效晶体硅（c-Si）太阳能电池和体硅晶圆的计量表征至关重要。在此，我们报告了在环境空气和温度下用Nafion对硅表面进行浸涂钝化，在高电阻率n型c-Si上实现了12 ms的最佳有效载流子寿命，这与最先进的钝化方法相当。Nafion是一种具有强路易斯酸性的非反应性聚合物，因此会在硅表面形成大量固定电荷，比传统薄膜钝化层所能达到的密度高1 - 2个数量级。值得注意的是，Nafion仅通过固定电荷钝化c-Si表面，而不对悬空键进行化学改性，这与将化学钝化与场效应钝化相结合的常规做法有根本区别。这种浸涂工艺简单且稳定，无需复杂设备或参数优化，因为不涉及化学反应。
