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Research Highlight

Mapping Photoinduced Ionic and Electronic Carrier Motion in Hybrid Perovskites

Time-resolved photoelectric carrier dynamics in hybrid perovskite films reveal stark differences at grain boundaries. With grain boundaries being slower to charge and discharge than the grain interior, believed to be due to more traps at the boundaries.

Scientific Achievement

Dynamics of light induced ionic and electronic carriers were mapped in 2D hybrid perovskite photovoltaics revealing substantial variations in optoelectronic response between grain interiors and grain boundaries.

Significance and Impact

Imaging photoinduced ionic motion in a 2D perovskite will identify more stable and efficient devices by revealing the role of grain boundaries.

Research Details

– Advanced time resolved SPM methods developed at CNMS were used to study photoinduced ion motion in 2D Ruddlesden−Popper Perovskite Films (C4H9NH3)2PbI4 (BAPI).
– Variations are observed in the photovoltage kinetics at the microsecond time scales associated with ionic motion and trapped electronic carriers.
– Surface photovoltage of the 2D grain boundaries evolve more slowly due to time-dependent band unbending.
 
R. Giridharagopal, J. T. Precht, S. Jariwala, L. Collins, S. Jesse, S. V. Kalinin, and D. S. Ginger, "Time-resolved electrical scanning probe microscopy of layered perovskites reveals spatial variations in photoinduced ionic and electronic carrier motion," ACS Nano (2019). DOI: 10.1021/acsnano.8b08390