NanoPlasmonic Sensing spectroscopy as a novel route for monitoring CH3NH3PbI3 perovskite formation in mesoporous TiO2 films

Here, we demonstrate a facile formation-controllable sequential deposition of CH3NH3PbI3 perovskite within a mesoporous TiO2 film by using a novel route of NanoPlasmonic Sensing (NPS). Insplorion Sensors, with plasmonic Au... [ view full abstract ]

Here, we demonstrate a facile formation-controllable sequential deposition of CH₃NH₃PbI₃ perovskite within a mesoporous TiO₂ film by using a novel route of NanoPlasmonic Sensing (NPS). Insplorion Sensors, with plasmonic Au nanodisks (diameter: 100 nm; height: 20 nm) with 10 nm dense layer of compact TiO₂ were initially spin coated with a mesoporous TiO₂ films (~350 nm -650 nm thickness and particle size <20 nm). The mesoporous TiO₂ films were infiltrated with PbI₂ solution by spin coating. For the in situ monitoring of perovskite formation, different concentrations of CH₃NH₃I at different operating temperatures were introduced into the above Au sensors/compact TiO₂/mesoporous TiO₂/PbI₂. The dynamics of CH₃NH₃PbI₃ perovskite formation at the lower interface of the mesoporous TiO₂ films can be monitored with this approach via the time-resolved spectral shifts of the Localized Surface Plasmon Resonance (LSPR) peak induced by the embedded plasmonic Au sensors. X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence (PL) measurements were further used to confirm the perovskite formation. This study suggests the viability of the current, developed experimental NPS approach for precise control of the standard two-step sequential solution deposition of CH₃NH₃PbI₃ perovskite, and thus to further improve the performance of photovoltaic and light-emitting based devices. In a broader context, it would offer a unique opportunity to detect minute local changes of several materials of interest at the localized interfaces either in solid or mesoporous systems.