钙钛矿太阳能电池/热电器件叠层的关键材料和结构设计研究

In recent years, the certified efficiency of organic - inorganic hybrid perovskite solar cells has already reached up to 22% due to their superior optoelectronic properties, such as suitable bandgap, which has triggered a strong interest by researchers. However, there still have some key issues to be solved so far: Firstly, the absorption range of perovskite is narrow, which can not effectively utilize infrared light. Those infrared light will transform into heat, increase the work temperature of solar cells, which greatly affects the power conversion efficiency and lifetime of photovoltaic devices. Secondly, the stability and power conversion efficiency of the device also need to be improved. In view of the above problems, this project will use perovskite solar cells and thermoelectric devices for the preparation of hybrid devices with innovation . Thermoelectric devices can transform infrared light and heat generated by solar cells. This project will mainly develop different transparent perovskite solar cells, study the effect of electrodes, perovskite thickness and band gap on the infrared transmittance of the upper device. The mechanism of the influence of infrared light and operating temperature on the device efficiency will be clarified. The effects of different thermoelectric devices, especially with TiS2 materials, interfacial absorption materials between thermoelectric and photovoltaic devices on the properties of the hybrid devices will be studied. Finally, the encapsulation and stability of the hybrid devices will be studied to develop a highly efficient and stable perovskite solar cell / thermoelectric hybrid device.

近些年来出现的有机无机杂化钙钛矿太阳能电池具有带隙可调等优异的光电性能，已达到高于22%的认证光电转换效率，引发了研究学者对于这种电池的研究热潮。但目前该电池也存在几个问题：第一，吸光范围较窄，不能有效利用红外光。且这些红外光转化成的热量会使电池工作的温度升高，极大地影响光伏电池的转化效率和寿命。第二，器件的稳定性和效率也有待提升。针对以上问题，本项目拟创新性采用钙钛矿电池和热电器件进行叠层，利用热电器件来利用红外光谱和电池工作时产生的热量，提高电池的效率和稳定性。本项目主要研究开发不同类型的透明钙钛矿电池，研究电极种类、钙钛矿厚度和带隙宽度对上层器件红外透光性影响；阐明红外光和电池工作温度对器件效率的影响机制；同时研究无毒低成本TiS2材料等不同热电器件以及界面吸收材料对于叠层器件性能的影响；最后，进行叠层器件的封装和稳定性研究，开发出高效稳定的钙钛矿电池/热电混合器件。

钙钛矿太阳能电池凭借其优异的光学和电学性质，成为近些年来的研究热点。但其仍存在光谱利用率不足、光热稳定性较差等问题。对此，将钙钛矿太阳能电池与热电器件结合形成叠层器件，可以有效提升太阳光利用率，同时降低工作温度，提升稳定性，具有很好的应用前景。但之前对这一叠层结构的研究很少，且主要集中在理论部分，缺乏系统性的实验探究。在项目执行期间，我们系统研究了串并联方式、水冷温度、钙钛矿材料带隙、光照强度等对叠层器件的性能影响。理论和实验结果均表明，电学连接方面，串联方式可提供更高的效率增益；温度方面，随水冷温度下降，热电两端温差及电压均有所提升；通过调节钙钛矿材料，叠层后的器件效率可从19.2%提升至24.1%，实现了25%的提升；光照强度方面，随光强增加，钙钛矿太阳能电池和叠层器件的效率均呈现先上升后下降的趋势。当聚焦度为3时，钙钛矿太阳能电池的光电转换效率达到最高值，约20.2%，叠层器件效率可达25.0%。我们还开发了超薄Au修饰的氧化铟锡(ITO)透明电极和NiOx纳米颗粒修饰的银纳米线透明电极，基于ITO制备的钙钛矿太阳能电池在800-1800 nm的平均透过率均达到65%以上。配合光热薄膜，可将透明电极钙钛矿太阳能电池效率从13.4%提升至16.7%。而在稳定性方面，通过界面钝化等方式制备了高稳定性的叠层器件，在低于10%RH干燥箱内放置60天后仍可维持效率90%以上，在85℃，85%RH加速老化实验中放置50 h 仍可维持初始效率的94%。综上所述，我们所制备的钙钛矿太阳能电池/热电叠层器件表现出了非常优异的光电特性和稳定性，具有非常光明的应用前景。基于本项目的资助，我们将理论模拟与实验研究相结合，深入探究了钙钛矿太阳能电池/热电叠层的太阳能光谱分配、叠层电学连接方式及工作温度、光照强度等参数对器件热学、电学、光电性能及稳定性的影响，为这一新型叠层结构的优化奠定了扎实的基础。