空气中制备高效率钙钛矿太阳能电池

PREPARATION OF HIGH-EFFICIENCY PEROVSKITE SOLAR CELLS IN AMBIENT AIR

王国良

11649104

硕士

材料物理与化学

程春

2018-06-04

2018-07-04

哈尔滨工业大学

深圳

伴随着以化石能源为代表的不可再生能源的不断消耗，人类所面临的能源危机和环境污染的压力越来越大，而太阳能作为一种取之不尽用之不竭的清洁能源，成为人类解决能源问题的希望。太阳能电池是一种具有光伏效应的器件，能够吸收光子而产生载流子，进而将光能转换为电能。新一代的钙钛矿太阳能电池，因具有带隙小、载流子扩散距离长、生产成本较低、能够做成柔性器件等优点而得到各国科学家们的青睐。虽然钙钛矿太阳能电池的光电转换效率已经达到 22.1%，接近硅太阳能电池的效率记录，但是依旧面临着严峻的挑战。因为钙钛矿材料本身很不稳定，容易与空气中的水氧发生反应而致使自身分解，导致电池失效。所以目前一些高效率的钙钛矿太阳能电池均是在惰性气体保护的手套箱中制备完成。而钙钛矿太阳能电池要想走向商业化，必须要实现空气中制备，于是我们便采用两种常见的钙钛矿太阳能电池的制备工艺，实现空气中制备钙钛矿太阳能电池。如果将手套箱中的旋涂制备钙钛矿薄膜的方法直接应用到空气中制备钙钛矿太阳能电池，则制得的太阳能电池的光电转换效极低，仅能达到 2.91%的光电转换效率，而将钙钛矿前驱体溶液及基片进行预热处理，则制备的钙钛矿太阳能电池的光电转换效率能够达到 11.62%，这里，我们采用一种自制的特殊装置，使其能够通过辐射，对旋转中的基片进行加热，从而增加溶剂挥发压力，进而能更好的抵制空气中的水对其的侵害，同时，通过这种方式的加热，也能够促进晶粒的生长，最终得到光滑致密均匀的大晶粒的钙钛矿薄膜。我们采用ITO/PEDOT:PSS/Perovskite/PCBM/BCP/Ag 的电池结构，最终在空气湿度 RH≤30%的开放空气中，制备出光电转换效率高达 17.29%的太阳能电池。并且这一方法将醋酸铅作为铅源，采用一步法在不需要反溶剂的情况下完成，实现了空气中绿色制备钙钛矿太阳能电池。虽然旋涂法制备出的钙钛矿薄膜比较均匀致密，但是无法进行大面积电池的制备依旧是这一方法不可避免的缺点。于是，我们又研究了另一种能够实现大面积钙钛矿太阳能电池生产制备的工艺-刮涂法制备钙钛矿太阳能电池。首先我们探究了温度、刮刀高度等工艺对所制备的钙钛矿太阳能电池的影响，在实验过程中，我们发现无水醋酸铅制备的钙钛矿太阳能电池的光电转换效率仅为 12.17%。而三水合醋酸铅为铅源的钙钛矿太阳能电池的效率能够达到 16.16%的光电转换效率，最后，我们采用 SEM、XRD等测试方法，探究出其原因，证明前驱体溶液中的水对晶体生长具有促进作用。

With the continuous depletion of non-renewable energy, the energy crisis and environmental pollution faced by human beings have become increasingly stressful. Solar energy, as an inexhaustible source of clean energy, will undoubtedly become the key to get rid of these issues. Solar cells are photovoltaic devices that can absorb photons and generate carriers, which in turn can convert light energy into electricity.The perovskite solar cells are favored by scientists from all over the world because of their low bandgap, long carrier diffusion distance, low production cost, and the ability to make flexible devices. At present, although the photoelectric conversion efficiency of perovskite solar cells has reached 22.1%, which is close to that of silicon solar cells, it still faces severe challenges. Because of the instability of perovskite material itself, it can easily reacts with water and oxygen in the air and causes itself to decompose, leading to battery failure. Therefore, most of the high-efficiency perovskite solar cells are currently prepared in glove boxes filled with inert gas. Preparing high-efficiency perovskite solar cells in ambient air is much more important for the commercialization. Therefore, we try to prepare high-efficiency perovskite solar cells in ambient air using two common perovskite solar cell manufacturing methods. If we prepare the perovskite solar cells in ambient air using spinning coating method in glove box filled with inert gas, the film will be composed of much pinholes, and as a result, the power conversion efficiency can only reach 2.91%. However, when we heat the perovskite precursor and the ITO covered by PEDOT: PSS, the morphology will change a lot. The film become much compact than that of room temperature spinning coating. And the efficiency increases to 11.62%. The result can indicate that the temperature plays an important role in the formation of perovskite. Therefore, we make a set of device by ourselves that can heat the perovskite precursor dropped on ITO during the rotation. Finally, we get the smooth, compact, uniform perovskite film. Heating of the precursor on ITO during rotation can speed the volatilization pressure of the solvent which can battle with water, in addition, the heating can also contribute to the growth of theperovskite grains. Here, we adopted a device structure of ITO/PEDOT:PSS/Perovskite/PCBM/BCP/Ag, and the PCE of the device reaches 17.29%.What’s more. In this one-step method, we use Pb(Ac)2.3H2O as the lead source, which can form high-quality perovskite film without the addition of anti-solvent, so it can make contribution to the environment. In conclusion, we get the high-quality perovskite film in ambient air using a kind of green method. However，this kind of method can not help to prepare large-area perovskite film.Then, we also study how to prepare high-quality perovskite film using blade coating method. We optimized the condition of the blade coating, such as temperature, distance between the blade knife and ITO substrate. During the optimization experiment，we found that the PCE of devices derived from Pb(Ac)2.3H2O was much higher than that of Pb(Ac)2. In order to understand the reason of that, SEM and XRD measurements were conducted. Finally, these results indicates that the moisture in perovskite precursor can contribute to the growth of grains and domains, which can help to decrease the defects in the film.

钙钛矿太阳能电池 空气中制备 旋涂法 刮涂法 热辐射

Perovskite solar cells Ambient air Spinning coating Blade coating Hot radiation

中文

联合培养

南方科技大学

王国良. 空气中制备高效率钙钛矿太阳能电池[D]. 深圳. 哈尔滨工业大学,2018.