Revealing the internal luminescence quantum efficiency of perovskite films via accurate quantification of photon recycling

Abstract

The internal luminescence quantum efficiency ($Q_{\mathrm{i}}^{\mathrm{lum}}$) provides an excellent assessment of the optoelectronic quality of semiconductors. To determine $Q_{\mathrm{i}}^{\mathrm{lum}}$ of perovskite films from the experimentally accessible external luminescence quantum efficiency ($Q_{\mathrm{e}}^{\mathrm{lum}}$) it is essential to account for photon recycling, and this requires knowledge of the photon escape probability ($p_{\mathrm{e}}$). Here, we establish an analysis procedure based on a curve fitting model that accurately determines $p_{\mathrm{e}}$ of perovskite films from photoluminescence (PL) spectra measured with a confocal microscope and an integrating sphere setup. We show that scattering-induced outcoupling of initially-trapped PL explains commonly observed red-shifted and broadened PL spectral shapes and leads to $p_{\mathrm{e}}$ being more than 10% higher in absolute terms compared to earlier assumptions. Applying our model to CH${}_3$NH${}_3$PbI${}_3$ films with exceptionally high $Q_{\mathrm{e}}^{\mathrm{lum}}$ up to 47.4% sets a real benchmark for $Q_{\mathrm{i}}^{\mathrm{lum}}$ at $78.0\pm 0.5\%$, revealing there is beyond a factor of two more scope for reducing non-radiative recombination than previously thought.

References in corpus (8)

• Intense Internal and External Fluorescence as Solar Cells Approach the Shockley-Queisser Efficiency Limit
• The perovskite/transport layer interfaces dominate non-radiative recombination in efficient perovskite solar cells
• Indirect to direct bandgap transition in methylammonium lead halide perovskite
• Local Crystal Misorientation Influences Non-Radiative Recombination
• Elucidating the long-range charge carrier mobility in metal halide perovskite thin films
• Shining Light on Photoluminescence Properties of Metal Halide Perovskites
• Comparative studies of optoelectrical properties of prominent PV materials: Halide Perovskite, CdTe, and GaAs
• Rigorous Treatment of Photon Recycling in Thermodynamics of Photovoltaics: The Case of Perovskite Thin-Film Solar Cells