Low-molecular-weight organic gelators are widely used to influence the solidification of polymers, with applications ranging from packaging items, food containers to organic electronic devices, including organic photovoltaics. Here, this concept is extended to hybrid halide perovskite-based materials. In situ time-resolved grazing incidence wide-angle X-ray scattering measurements performed during spin coating reveal that organic gelators beneficially influence the nucleation and growth of the perovskite precursor phase. This can be exploited for the fabrication of planar n-i-p heterojunction devices with MAPbI3 (MA = CH3NH3+) that display a performance that not only is enhanced by ≈25% compared to solar cells where the active layer is produced without the use of a gelator but that also features a higher stability to moisture and a reduced hysteresis. Most importantly, the presented approach is straightforward and simple, and it provides a general method to render the film formation of hybrid perovskites more reliable and robust, analogous to the control that is afforded by these additives in the processing of commodity “plastics.”
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: S.C. and A.L. acknowledge Regione Puglia and ARTI for funding FIR—future in research projects “PeroFlex” project no. LSBC6N4 and “HyLight” project no. GOWMB21. The authors acknowledge the project Progetto di ricerca PON MAAT (Project Number: PON02_00563_3316357) and PERSEO-“PERovskite-based solar cells: towards high efficiency and long-term stability” (Bando PRIN 2015-Italian Ministry of University and Scientific Research (MIUR) Decreto Direttoriale 4 novembre 2015 n. 2488, project number 20155LECAJ) for funding. A.R. and S.M. gratefully acknowledge SIR project “Two-Dimensional Colloidal Metal Dichalcogenides based Energy-Conversion Photovoltaics” (2D ECO), Bando SIR (Scientific Independence of young Researchers) 2014 MIUR Decreto Direttoriale 23 gennaio 2014 no. 197 (project number RBSI14FYVD, CUP: B82I15000950008) for funding. The authors acknowledge Sonia Carallo for technical support. N.D.T. acknowledges support from the National Science Foundation's International Research Fellowship Program (OISE-1201915) and the European Research Council's Marie Curie International Incoming Fellowship under grant agreement number 300091. N.S. is by a European Research Council Starting Independent Researcher Fellowship under grant agreement number 279587. We thank Dr. Detlef-M. Smilgies from the Cornell High Energy Synchrotron Source (CHESS) for his assistance with in situ GIWAXS measurements. CHESS is supported by the NSF & NIH/NIGMS via NSF award DMR-1332208. A.A. and R.M. are thankful for the support of the King Abdullah University of Science and Technology (KAUST) and the KAUST Solar Center.