@article { WOS:000388504800028,
	title = {Cs<sup>+</sup> incorporation into CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub> perovskite: substitution limit and stability enhancement},
	journal = {JOURNAL OF MATERIALS CHEMISTRY A},
	volume = {4},
	number = {45},
	year = {2016},
	pages = {17819-17827},
	abstract = {In this study we systematically explored the mixed cation perovskite Cs-x(CH3NH3)(1-x)PbI3. We exchanged the A-site cation by dipping MAPbI(3) films into a CsI solution, thereby incrementally replacing the MA(+) in a time-resolved dipping process and analysed the resulting thin-films with UV-Vis, XRD, EDAX, SEM and optical depth-analysis in a high-throughput fashion. Additional in situ UV-Vis and time-resolved XRD measurements allowed us to look at the kinetics of the formation process. The results showed a discontinuity during the conversion. Firstly, small amounts of Cs+ are incorporated into the structure. After a few minutes, the Cs content approaches a limit and grains of delta-CsPbI3 occur, indicating a substitution limit. We compared this cation exchange to a one-step crystallisation approach and found the same effect of phase segregation, which shows that the substitution limit is an intrinsic feature rather than a kinetic effect. Optical and structural properties changed continuously for small Cs incorporations. Larger amounts of Cs result in phase segregation. We estimate the substitution limit of Cs(x)MA(1-x)PbI(3) to start at a Cs ratio x = 0.13, based on combined measurements of EDAX, UV-Vis and XRD. The photovoltaic performance of the mixed cation perovskite shows a large increase in device stability from days to weeks. The initial efficiency of mixed Cs(x)MA(1-x)PbI(3) devices decreases slightly, which is compensated by stability after a few days.},
	issn = {2050-7488},
	doi = {10.1039/c6ta05869h},
	url = {https://researchportal.bath.ac.uk/en/publications/cssupsup-incorporation-into-chsub3subnhsub3subpbisub3sub-perovski},
	author = {Niemann, Ralf G. and Gouda, Laxman and Hu, Jiangang and Tirosh, Shay and Gottesman, Ronen and Cameron, Petra J. and Zaban, Arie}
}
