Imaging photoinduced surface potentials on hybrid perovskites by real-time Scanning Electron Microscopy

Publication date: Available online 20 March 2019Source: MicronAuthor(s): Gabriele Irde, Silvia Maria Pietralunga, Vittorio Sala, Maurizio Zani, James M. Ball, Alex J Barker, Annamaria Petrozza, Guglielmo Lanzani, Alberto TagliaferriAbstractWe introduce laser-assisted Time-Resolved SEM (TR-SEM), joining Scanning Electron Microscopy and laser light excitation, to probe the long-term temporal evolution of optically excited charge distributions at the surface of Metal Ammonium Lead Triiodide (MAPbI3) hybrid perovskite thin films. Laser-assisted TR-SEM relies on the optically induced local modification of Secondary Electron (SE) detection yield to provide mapping of photoexcited potentials and charge dynamics at surfaces, and qualifies as a complementary approach to near-field probe microscopies and nonlinear photoemission spectroscopies for photovoltage measurements. Real-time imaging of evolving field patterns are provided on timescales compatible with SEM scanning rates, so that temporal resolution in the millisecond range can be ultimately envisaged.. MAPbI3 is an outstanding light-sensitive material candidate for applications in solar light harvesting and photovoltaics, also appealing as an active system for light generation. In this work, the real time temporal evolution of optically induced SE contrast patterns in MAPbI3 is experimentally recorded, both under illumination by a 405 nm blue laser and after light removal, showing the occurrence of modifications related to ph...

Source: Micron - March 21, 2019 Category: Biology Source Type: research