Jinhyun Kim1 Taehyun Hwang1 Byungho Lee1 Sangheon Lee1 Bumjin Gil1 Kimin Park1 Byungwoo Park1

1, Seoul National University, Seoul, , Korea (the Republic of)

Studies of organometallic perovskite solar cells have been remarkably grown within several years, but still with the concerns of poor stability and insufficient power conversion efficiency (PCE). To overcome the limit from these concerns, modification of perovskite materials should be addressed [1-3]. Herein, we have demonstrated imidazole (C3H4N2) as a cation dopant for conventional methylammonium lead iodide (MAPbI3). Being aromatic hydrocarbon species with small ionic radius, imidazole cations were appropriately alloyed with MAPbI3 [4]. Also, delocalized π-bond in imidazole allowed the formation of unprecedented kind of hybrid perovskite with both high electrical conductivity and stability. Optimal content of imidazole incorporated in MAPbI3 led to the improved PCE approaching ~18.0% with negligible hysteresis, and both materials and device stability were largely improved when stored in various conditions, such as air, light, and high temperature. Also, devices with large active area of 2 cm2 exhibited PCE as high as ~12.2%, further addressing the effect of imidazole on the formation of high quality nanostructures and devices.

[1] J. Kim, T. Hwang, S. Lee, B. Lee, J. Kim, G. S. Jang, S. Nam, and B. Park, Sci. Rep. 6, 25648 (2016).
[2] T. Hwang, B. Lee, J. Kim, S. Lee, B. Gil, A. J. Yun, and B. Park, Adv. Mater. (2017) (accepted).
[3] J. Lu, L. Jiang, W. Li, F. Li, N. K. Pai, A. D. Scully, C.-M. Tsai, U. Bach, A. N. Simonov, Y.-B. Cheng, and L. Spiccia, Adv. Energy Mater. 7, 1700444 (2017).
[4] G. Kieslich, S. Sun, and A. K. Cheetham, Chem. Sci. 5, 4712 (2014).
Corresponding Author: Byungwoo Park: