Tavakoli Mohammad Mahdi, Lin Qingfeng, Leung Siu-Fung, Lui Ga Ching, Lu Hao, Li Liang, Xiang Bin, Fan Zhiyong
Department of Electronic and Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China.
College of Physics, Optoelectronics and Energy, Jiangsu Key Laboratory of Thin Films, Soochow University, Suzhou, 215006, P. R. China.
Nanoscale. 2016 Feb 21;8(7):4276-83. doi: 10.1039/c5nr08836d.
Utilization of nanostructures on photovoltaic devices can significantly improve the device energy conversion efficiency by enhancing the device light harvesting capability as well as carrier collection efficiency. However, improvements in device mechanical robustness and reliability, particularly for flexible devices, have rarely been reported with in-depth understanding. In this work, we fabricated efficient, flexible and mechanically robust organometallic perovskite solar cells on plastic substrates with inverted nanocone (i-cone) structures. Compared with the reference cell that was fabricated on a flat substrate, it was shown that the device power conversion efficiency could be improved by 37%, and reached up to 11.29% on i-cone substrates. More interestingly, it was discovered that the performance of an i-cone device remained more than 90% of the initial value even after 200 mechanical bending cycles, which is remarkably better than for the flat reference device, which degraded down to only 60% in the same test. Our experiments, coupled with mechanical simulation, demonstrated that a nanostructured template can greatly help in relaxing stress and strain upon device bending, which suppresses crack nucleation in different layers of a perovskite solar cell. This essentially leads to much improved device reliability and robustness and will have significant impact on practical applications.
在光伏器件上利用纳米结构可以通过增强器件的光捕获能力以及载流子收集效率来显著提高器件的能量转换效率。然而，对于器件机械强度和可靠性的提升，特别是对于柔性器件，鲜有深入研究的报道。在这项工作中，我们在具有倒置纳米锥（i-锥）结构的塑料基板上制备了高效、柔性且机械强度高的有机金属钙钛矿太阳能电池。与在平坦基板上制备的参考电池相比，结果表明器件的功率转换效率可提高37%，在i-锥基板上可达11.29%。更有趣的是，发现即使经过200次机械弯曲循环，i-锥器件的性能仍保持在初始值的90%以上，这明显优于平坦的参考器件，后者在相同测试中性能下降至仅60%。我们的实验结合力学模拟表明，纳米结构模板在器件弯曲时能极大地帮助缓解应力和应变，从而抑制钙钛矿太阳能电池不同层中的裂纹形成。这从本质上提高了器件的可靠性和强度，将对实际应用产生重大影响。
