  We present a novel analytical model for analysing the spectral
photoluminescence quantum yield of non-planar semiconductor thin films. This
model considers the escape probability of luminescence and is applied to
triple-cation perovskite thin films with a 1-Sun photoluminescence quantum
yield approaching 25%. By using our model, we can decouple the internal
radiative, external radiative, and non-radiative bi-molecular recombination
coefficients. Unlike other techniques that measure these coefficients
separately, our proposed method circumvents experimental uncertainties by
avoiding the need for multiple photoluminescence measurement techniques. We
validate our model by comparing the extracted implied open-circuit voltage,
effective luminescence escape probabilities, absorptivity, and absorption
coefficient with values obtained using established methods and found that our
results are consistent with previous findings. Next, we compare the implied
1-Sun radiative open-circuit voltage and radiative recombination current
obtained from our method with literature values. We then convert the implied
open-circuit voltage and implied radiative open-circuit voltage to the
injection-dependent apparent-effective and apparent-radiative carrier
lifetimes, which allow us to decouple the different recombination coefficients.
Using this lifetime analysis, we predict the efficiency losses due to each
recombination mechanism. Our proposed analytical model provides a reliable
method for analysing the spectral photoluminescence quantum yield of
semiconductor thin films, which will facilitate further research into the
photovoltaic properties of these materials.
