Efficiently Improving the Stability of Inverted Perovskite Solar Cells by Employing Polyethylenimine-Modified Carbon Nanotubes as Electrodes

• Published in: ACS applied materials & interfaces Vol. 10; no. 37; pp. 31384 - 31393
• Main Authors: Zhou, Yu, Yin, Xuewen, Luo, Qiang, Zhao, Xingyue, Zhou, Duanliang, Han, Jianhua, Hao, Feng, Tai, Meiqian, Li, Jianbao, Liu, Peng, Jiang, Kaili, Lin, Hong
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 19.09.2018
• Subjects: PEI modification; carbon electrodes; energy level alignment; interfacial charge transfer; stability
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.8b10253

Inverted perovskite solar cells (PSCs) have been becoming more and more attractive, owing to their easy-fabrication and suppressed hysteresis, while the ion diffusion between metallic electrode and perovskite layer limit the long-term stability of devices. In this work, we employed a novel polyethylenimine (PEI) modified cross-stacked superaligned carbon nanotube (CSCNT) film in the inverted planar PSCs configurated FTO/NiO x /methylammonium lead tri-iodide (MAPbI3)/6, 6-phenyl C61-butyric acid methyl ester (PCBM)/CSCNT:PEI. By modifying CSCNT with a certain concentration of PEI (0.5 wt %), suitable energy level alignment and promoted interfacial charge transfer have been achieved, leading to a significant enhancement in the photovoltaic performance. As a result, a champion power conversion efficiency (PCE) of ∼11% was obtained with a V oc of 0.95 V, a J sc of 18.7 mA cm–2, a FF of 0.61 as well as negligible hysteresis. Moreover, CSCNT:PEI based inverted PSCs show superior durability in comparison to the standard silver based devices, remaining over 85% of the initial PCE after 500 h aging under various conditions, including long-term air exposure, thermal, and humid treatment. This work opens up a new avenue of facile modified carbon electrodes for highly stable and hysteresis suppressed PSCs.