Ma Junjie, Yang Guang, Qin Minchao, Zheng Xiaolu, Lei Hongwei, Chen Cong, Chen Zhiliang, Guo Yaxiong, Han Hongwei, Zhao Xingzhong, Fang Guojia
Key Lab of Artificial Micro- and Nano-Structures of Ministry of Education of China School of Physics and Technology Wuhan University Wuhan 430072 P. R. China.
Wuhan National Lab on Opto-electronics Huazhong University of Science and Technology Wuhan 430074 P. R. China.
Adv Sci (Weinh). 2017 May 2;4(9):1700031. doi: 10.1002/advs.201700031. eCollection 2017 Sep.
Reducing the energy loss and retarding the carrier recombination at the interface are crucial to improve the performance of the perovskite solar cell (PSCs). However, little is known about the recombination mechanism at the interface of anode and SnO electron transfer layer (ETL). In this work, an ultrathin wide bandgap dielectric MgO nanolayer is incorporated between SnO:F (FTO) electrode and SnO ETL of planar PSCs, realizing enhanced electron transporting and hole blocking properties. With the use of this electrode modifier, a power conversion efficiency of 18.23% is demonstrated, an 11% increment compared with that without MgO modifier. These improvements are attributed to the better properties of MgO-modified FTO/SnO as compared to FTO/SnO, such as smoother surface, less FTO surface defects due to MgO passivation, and suppressed electron-hole recombinations. Also, MgO nanolayer with lower valance band minimum level played a better role in hole blocking. When FTO is replaced with Sn-doped InO (ITO), a higher power conversion efficiency of 18.82% is demonstrated. As a result, the device with the MgO hole-blocking layer exhibits a remarkable improvement of all parameters. This work presents a new direction to improve the performance of the PSCs based on SnO ETL by transparent conductive electrode surface modification.
减少能量损失并抑制界面处的载流子复合对于提高钙钛矿太阳能电池（PSC）的性能至关重要。然而，关于阳极与SnO电子传输层（ETL）界面处的复合机制却知之甚少。在这项工作中，在平面PSC的SnO:F（FTO）电极与SnO ETL之间引入了超薄宽带隙介电MgO纳米层，实现了增强的电子传输和空穴阻挡性能。使用这种电极改性剂后，功率转换效率达到了18.23%，与未使用MgO改性剂的情况相比提高了11%。这些改进归因于MgO改性的FTO/SnO相较于FTO/SnO具有更好的性能，如表面更光滑、由于MgO钝化导致的FTO表面缺陷更少以及电子-空穴复合受到抑制。此外，价带最小能级较低的MgO纳米层在空穴阻挡方面发挥了更好的作用。当用掺锡的氧化铟（ITO）替代FTO时，功率转换效率更高，达到了18.82%。结果，具有MgO空穴阻挡层的器件在所有参数上都有显著提高。这项工作为通过透明导电电极表面改性来提高基于SnO ETL的PSC性能提供了一个新方向。
