CREATIVE

Correlating Defect Densities with Recombination Losses in Halide-Perovskite Solar Cells

State-of-the-art perovskite solar cells show substantial voltage losses with respect to their thermodynamic limit, due to non-radiative recombination losses associated with distributions of defect densities within the perovskite bulk and its interfaces with the transport layers. The estimation of these defect densities using traditional electrical techniques are hampered by the large geometric capacitance of the thin-film PSCs, which hides the response from the defect density and provides an upper limit of resolution below which the defect density cannot be known.

In this project, we tackle this problem by improving the resolution power of these techniques by moving from vertical (sandwich) devices to lateral devices. Furthermore, advanced characterization is carried out using a suite of time-domain, frequency-domain and luminescence methods, combined with drift-diffusion simulations and Bayesian parameter estimation methods for accurate parameter estimation from experimental data. This characterization strategy will lead to a fundamental correlation between experimentally-measured defect densities, lifetimes and the voltage losses, which has not been achieved so far

Figure 1 Summary of key challenges faced in perovskite solar cell characterization and the proposed solutions to overcome them in the CREATIVE project.