TIME DEPENDENT ELECTROLUMINESCENCE IN PLANAR AND MESOPOROUS METHYLAMMONIUM LEAD IODIDE SOLAR CELLS

WALTER HERRERA; TARETTO, KURT; MATÍAS CÓRDOBA; DOLORES PEREZ, MARÍA; KOFFMAN-FRISCHKNECHT, ALEJANDRO

Marsella

Conferencia; 36th European Photovoltaic Solar Energy Conference and Exhibition; 2019

WIP GmbH & Co Planungs-KG

Electroluminescence (EL) characterization in conventional methylammonium lead iodide perovskite solar cells is performed under constant current and constant voltage biasing conditions. The total electroluminescence is measured as a function of time after polarization, revealing pronounced transient behavior in cells with both planarand mesoporous TiO2 electron transport layers. The EL signals show an increase up to a maximum typically occurring around 5 s and 10 s after biasing for planar and mesoporous cells, respectively. Compared to the planar TiO2 cells, the mesoporous TiO2 cells show slower EL transients. The EL decay after the maximum saturates towards values around 10 % of the maximum at times above 15 s and 30 s for planar and mesoporous cells, respectively. After discarding current heating effects, we discuss possible microscopic origins of the observed transients by taking into account ion transport occurring upon polarization. The non-monotonous EL curve showing a peak is discussed interms of ion-migration originating a tradeoff between electric field compensation and non-radiative recombination at vacancy generation upon migration.