Electronic Supplementary material (ESI) for Replacement of n-type layers with non-toxic APTES interfacial layers to improve the performance of amorphous Si thin-film solar cells Hassan Hafeez 1,a) , Dae Keun Choi 1,a) , Chang Min Lee 1,a) , P. Justin Jesuraj 1 , Dong Hyun Kim 1 , Aeran Song 2 , Kwun Bum Chung 2 , Myungkwan Song 3 , Jun Fei Ma 3 , Chang-Su Kim 3, *, and Seung Yoon Ryu 1, * 1 Division of Display and Semiconductor Physics, Display Convergence, College of Science and Technology, Korea University Sejong Campus 2511 Sejong-ro, Sejong City, 30019, Republic of Korea 2 Division of Physics and Semiconductor Science, Dongguk University, Seoul 04620, Republic of Korea 3 Advanced Nano-Surface Department, Korea Institute of Materials Science (KIMS) Changwon, 51508, Republic of Korea * Author to whom the correspondence should be addressed; e-mail: justie74@korea.ac.kr, cskim1025@kims.re.kr a) These authors contributed equally to this paper. 1 Electronic Supplementary Material (ESI) for RSC Advances. This journal is © The Royal Society of Chemistry 2019