• H., Friend R.
• Vru Ini, M.
• J., Beeson H.
• Crespo-Quesada, M.
• J., Snaith H.
• Ehrler, B.
• Vrućinić, M.
• Alsari, M.
• Friend, Richard, H.
• Snaith, H. J.
• Richter, J. M.
• Beeson, H. J.
• Pazos-Outón, L. M.
• Abdi-Jalebi, M.
• Szumilo, M.
• M., Pazos-Outon L.
• M., Richter J.
• Lamboll, R.
• Deschler, F.

Abstract

Lead-halide perovskites have emerged as high-performance photovoltaic materials. We mapped the propagation of photogenerated luminescence and charges from a local photoexcitation spot in thin films of lead tri-iodide perovskites. We observed light emission at distances of ≥50 micrometers and found that the peak of the internal photon spectrum red-shifts from 765 to ≥800 nanometers. We used a lateral-contact solar cell with selective electron- and hole-collecting contacts and observed that charge extraction for photoexcitation >50 micrometers away from the contacts arose from repeated recycling between photons and electron-hole pairs. Thus, energy transport is not limited by diffusive charge transport but can occur over long distances through multiple absorption-diffusion-emission events. This process creates high excitation densities within the perovskite layer and allows high open-circuit voltages.

Topics

• perovskite
• impedance spectroscopy
• thin film
• extraction
• luminescence