@article { ISI:000445439900064,
	title = {Solution-Processed Cu9S5 as a Hole Transport Layer for Efficient and Stable Perovskite Solar Cells},
	journal = {ACS APPLIED MATERIALS \&amp; INTERFACES},
	volume = {10},
	number = {37},
	year = {2018},
	month = {SEP 19},
	pages = {31535-31540},
	abstract = {Organic inorganic perovskite solar cells have seen tremendous developments in recent years. As a hole transport material, 2,2\&$\#$039;,7,7\&$\#$039;-tetrakis(N,N-di-p-methoxyphenylamine)-9,9\&$\#$039;-spirobifluorene (Spiro-OMe-TAD) is widely used in n-i-p perovskite solar cells. However, it may lead to the perovskite film degradation due to the dopant lithium bis-((trifluoromethyl)sulfonyl)amide (Li-TFSI), which has strong hydrophilicity. Cu9S5 is considered as a superior p-type transport material, which also has a favorable energy level matching with the highest occupied molecular orbital of Spiro-OMeTAD. Herein, a solution-processed organic-inorganic-integrated hole transport layer was reported, which is composed of the undoped Spiro-OMeTAD and Cu9S5 layer. Since there is no Li-TFSI doping, it is extremely conductive to the long-term stability of the solar cells. In the meantime, we proposed a method to adjust the lowest unoccupied molecular orbital (LUMO) of SnO2 via nitrogen implantation (N:SnO2). The LUMO of SnO2 can be tuned from -4.33 to -3.91 eV, which matches well with the LUMO of CH3NH3PbI3 (-3.90 eV), and thus helps to reduce hysteresis. The modified hole and electron transport layers were applied in n-i-p perovskite solar cells, which achieve a maximum power conversion efficiency (PCE) of 17.10 and 96\% retention of PCE after 1200 h in air atmosphere without any encapsulation.},
	issn = {1944-8244},
	doi = {10.1021/acsami.8b08888},
	author = {Dong Han and Wu, Cuncun and Zhang, Qaohui and Wei, Shiyuan and Qi, Xin and Zhao, Yunbiao and Chen, Yi and Chen, Yuhan and Xiao, Lixin and Zhao, Ziqiang}
}
