Available on-demand - F.EL02.06.05
Study of The Synergetic Effects of Chloride and Surfactants Additions on Perovskite Crystallisation, in a Slot-Die Coating Process for Large-Scale Fabrication
Sophie Bernard1,2,3,Sébastien Juteau1,2,Armelle Yaiche1,2,Stefania Cacovich4,Frederic Sauvage3,Jean Rousset1,2
EDF R&D1,IPVF (Institut Photovotaïque d'Ile de France)2,CNRS, UPJV Université Picardie Jules Verne3,CNRS UMR 90064
For the past ten years, perovskite solar cells have known a tremendous development among photovoltaic technologies, rapidly increasing from 3,8%  to 25.2%  power conversion efficiency (PCE). However, before transferring this technology to commercial applications, one of the main challenges to overcome is the fabrication of high quality perovskite absorber films on large surfaces. Various alternatives to spin-coating have been explored in the literature such as blade coating , inkjet coating , roll-to-roll  or spray coating . But, slot-die coating is one of the most promising techniques. It is easily compatible with high rate fabrication technique like roll-to-roll and allows a sharp control over the uniformity on large surfaces.
In this work, we emphasis on the influence of the drying method upon the absorber properties. After the slot-die coating deposition, we chose to use a vacuum quench method, which allow a uniform extraction of the solvent, few minutes before annealing. The change of the quench system, from anti-solvent to vacuum aspiration, modify the speed with which the solvent is extracted. Then, it is possible to influence the crystallization mechanisms to fit the new drying environment by changing the perovskite ink composition. We herein propose a method to fabricate CsFA perovskite with a double-additives protocol, combining a surfactant and chloride addition through MACl.
A particular difficult challenge is to isolate the action of the surfactant and the chloride during crystallization. We combined PL and morphological characterisations, under different annealing and quench conditions, in order to successfully bring their respective effects out. For example, including MACl into precursor solutions seem to increase the film coverage and grain sizes during secondary grain growth, generating a smooth and pinhole-free perovskite layer with large grain size while surfactant enhance film uniformity and passivate surface defects. We reached over 16% PCE on small-scale cells (0.09 cm2 aperture) with optimized ratio of chloride, thermal annealing and vacuum conditions.
This approach offers a better understanding of perovskite growth under large-scale fabrication conditions and is an important step towards industrial perovskite devices.
 A. Kojima, et al., J. Am. Chem. Soc., vol. 131, no. 17, pp. 6050–6051, May 2009, doi: 10.1021/ja809598r.
 NREL, ‘Best research-cells efficiency’, 2020.
 Y. Deng, et al., Energy & Environmental Science, vol. 8, no. 5, pp. 1544–1550, 2015, doi: 10.1039/C4EE03907F.
 F. Mathies, et al., ACS Applied Energy Materials, vol. 1, no. 5, pp. 1834–1839, May 2018, doi: 10.1021/acsaem.8b00222.
 C. Zuo, et al., Nano Energy, vol. 46, pp. 185–192, Apr. 2018, doi: 10.1016/j.nanoen.2018.01.037.
 Y. Jiang et al., Nano Energy, vol. 53, pp. 440–448, Nov. 2018, doi: 10.1016/j.nanoen.2018.08.062.