@article{c82eb87080284e628c30556586203fc7,
title = "Aligned and Graded Type-II Ruddlesden–Popper Perovskite Films for Efficient Solar Cells",
abstract = "Recently, Ruddlesden–Popper perovskites (RPPs) have attracted increasing interests due to their promising stability. However, the efficiency of solar cells based on RPPs is much lower than that based on 3D perovskites, mainly attributed to their poor charge transport. Herein, a simple yet universal method for controlling the quality of RPP films by a synergistic effect of two additives in the precursor solution is presented. RPP films achieved by this method show (a) high quality with uniform morphology, enhanced crystallinity, and reduced density of sub-bandgap states, (b) vertically oriented perovskite frameworks that facilitate efficient charge transport, and (c) type-II band alignment that favors self-driven charge separation. Consequently, a hysteresis-free RPP solar cell with a power conversion efficiency exceeding 12%, which is much higher than that of the control device (1.5%), is achieved. The findings will spur new developments in the fabrication of high-quality, aligned, and graded RPP films essential for realizing efficient and stable perovskite solar cells.",
keywords = "2D, additives, charge separation, layered perovskite, solar cells",
author = "Jian Qing and Liu, {Xiao Ke} and Mingjie Li and Feng Liu and Zhongcheng Yuan and Elizaveta Tiukalova and Zhibo Yan and Martial Duchamp and Shi Chen and Yuming Wang and Sai Bai and Liu, {Jun Ming} and Snaith, {Henry J.} and Lee, {Chun Sing} and Sum, {Tze Chien} and Feng Gao",
note = "Funding Information: J.Q., X.K.L., and M.L. contributed equally to this work. This work was supported by the Research Grants Council of the Hong Kong Special Administrative Region, China (Project No. 11304115), the National Natural Science Foundation of China (No. 51473138), the Joint NTU-LiU Ph.D. programme on Materials and Nanoscience, the Swedish Research Council VR (Grant No. 330-2014-6433), the European Commission Marie Sk?odowska-Curie action (Grant Nos. INCA 600398 and 691210), and the Swedish Government Strategic Research Area in Materials Science on Functional Materials at Link?ping University (Faculty Grant SFO-Mat-LiU No. 2009-00971). T.C.S. acknowledges the financial support from Nanyang Technological University start-up grant M4080514; the Ministry of Education Academic Research Fund Tier 1 grants RG101/15 and RG173/16, and Tier 2 grants MOE2014-T2-1-044, MOE2015-T2-2-015, and MOE2016-T2-1-034; and from the Singapore National Research Foundation through the Competitive Research Program NRF-CRP14-2014. X.K.L. would like to thank the VINNMER and Marie Sk?odowska-Curie Fellowship (2016-02051) provided by Vinnova. The authors thank Quanzheng Tao (Link?ping University) for assisting XRD measurements. The TEM measurement was performed at the Facility for Analysis, Characterization, Testing and Simulation (FACTS) in Nanyang Technological University, Singapore. Funding Information: J.Q., X.K.L., and M.L. contributed equally to this work. This work was supported by the Research Grants Council of the Hong Kong Special Administrative Region, China (Project No. 11304115), the National Natural Science Foundation of China (No. 51473138), the Joint NTU-LiU Ph.D. programme on Materials and Nanoscience, the Swedish Research Council VR (Grant No. 330-2014-6433), the European Commission Marie Sk{\l}odowska-Curie action (Grant Nos. INCA 600398 and 691210), and the Swedish Government Strategic Research Area in Materials Science on Functional Materials at Link{\"o}ping University (Faculty Grant SFO-Mat-LiU No. 2009-00971). T.C.S. acknowledges the financial support from Nanyang Technological University start-up grant M4080514; the Ministry of Education Academic Research Fund Tier 1 grants RG101/15 and RG173/16, and Tier 2 grants MOE2014-T2-1-044, MOE2015-T2-2-015, and MOE2016-T2-1-034; and from the Singapore National Research Foundation through the Competitive Research Program NRF-CRP14-2014. X.K.L. would like to thank the VINNMER and Marie Sk{\l}odowska-Curie Fellowship (2016-02051) provided by Vinnova. The authors thank Quanzheng Tao (Link{\"o}ping University) for assisting XRD measurements. The TEM measurement was performed at the Facility for Analysis, Characterization, Testing and Simulation (FACTS) in Nanyang Technological University, Singapore. Publisher Copyright: {\textcopyright} 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim",
year = "2018",
month = jul,
day = "25",
doi = "10.1002/aenm.201800185",
language = "English",
volume = "8",
journal = "Advanced Energy Materials",
issn = "1614-6832",
publisher = "John Wiley and Sons Inc.",
number = "21",
}
