  The establishment of a rigorous theory on thermodynamics of light management
in photovoltaics that accommodates various loss mechanisms as well as
wave-optical effects in the absorption and reemission of light is at stake in
this contribution. To this end, we propose a theoretical framework to calculate
the open-circuit voltage enhancement resulting from photon recycling ($\Delta
V^{\mathrm{PR}}_{\mathrm{oc}}$) with rigorous wave-optical treatment. It can be
applied to both planar thin-film and nanostructured single-junction solar
cells. We derive an explicit expression for $\Delta
V^{\mathrm{PR}}_{\mathrm{oc}}$, which reveals its dependence on internal
quantum luminescence efficiency, parasitic reabsorption, and on photon escape
probabilities of reemmited photons. While the internal quantum luminescence
efficiency is an intrinsic material property, both latter quantities can be
determined rigorously for an arbitrary solar cell architecture by
three-dimensional electrodynamic dipole emission calculations. We demonstrate
the strengths and validity of our framework by determining the impact of photon
recycling on the $V_{\mathrm{oc}}$ of a conventional planar organo-metal halide
perovskite thin-film solar cell and compare it to established reference cases
with perfect antireflection and Lambertian light scattering. Our calculations
reveal $\Delta V^{\mathrm{PR}}_{\mathrm{oc}}$ values of up to 80 mV for the
considered device stack in the absence of angular restriction and up to 240 mV
when the escape cone above the cell is restricted to
$\theta_{\mathrm{out}}=2.5^\circ$ around the cell normal. These improvements
impose severe constraints on the parasitic absorption as a parasitic
reabsorption probability of only 2\% reduces the $\Delta
V^{\mathrm{PR}}_{\mathrm{oc}}$ to 100 mV for the same angular restriction. Our
work here can be used to provide design guidelines.
