Energy Research Institute @NTU (ERI@N), Nanyang Technological University , Research Techno Plaza, X-Frontier Block, Level 5, 50 Nanyang Drive 637553, Singapore.
Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University , 21 Nanyang Link 637371, Singapore.
ACS Appl Mater Interfaces. 2017 Jun 28;9(25):21292-21297. doi: 10.1021/acsami.7b05133. Epub 2017 Jun 13.
Owing to improvements in film morphology, crystallization process optimization, and compositional design, the power conversion efficiency of perovskite solar cells has increased from 3.8 to 22.1% in a period of 5 years. Nearly defect-free crystalline films and slow recombination rates enable polycrystalline perovskite to boast efficiencies comparable to those of multicrystalline silicon solar cells. However, volatile low melting point components and antisolvent treatments essential for the processing of dense and smooth films often lead to surface defects that hamper charge extraction. In this study, we investigate methylammonium bromide (MABr) surface treatments on perovskite films to compensate for the loss of volatile cation during the annealing process for surface defect passivation, grain growth, and a bromide-rich top layer. This facile method did not change the phase or bandgap of perovskite films yet resulted in a significant increase in the open circuit voltages of devices. The devices with 10 mM MABr treatment show 2% improvement in absolute power conversion efficiency over the control sample.
由于在薄膜形态、结晶过程优化和组成设计方面的改进，钙钛矿太阳能电池的能量转换效率在 5 年内从 3.8%提高到了 22.1%。近乎无缺陷的结晶薄膜和缓慢的复合速率使多晶钙钛矿能够与多晶硅太阳能电池相媲美。然而，对于致密光滑薄膜的加工必不可少的挥发性低熔点成分和反溶剂处理常常导致表面缺陷，阻碍电荷提取。在这项研究中，我们研究了甲脒溴（MABr）对钙钛矿薄膜的表面处理，以补偿在退火过程中挥发性阳离子的损失，从而实现表面缺陷钝化、晶粒生长和富含溴的顶层。这种简便的方法没有改变钙钛矿薄膜的相或能隙，但却显著提高了器件的开路电压。经过 10mM MABr 处理的器件的绝对能量转换效率比对照样品提高了 2%。
