Reconciliation of dipole emission with detailed balance rates for the simulation of luminescence and photon recycling in perovskite solar cells.

A theoretical description of light emission, propagation and re-absorption in semiconductor multilayer stacks is derived based on the transverse Green's function of the electromagnetic field in the presence of a complex dielectric. The canonical dipole emission model is parametrized in terms of the local optical material constants and the local quasi-Fermi level splitting using the detailed balance relation between local absorption and emission rates. The framework obtained in this way is shown to reproduce the generalized Kirchhoff relations between the luminescent emission from metal halide perovskite slabs under uniform excitation and the slab absorptance of light with arbitrary angle of incidence.

Draw-spun, photonically annealed Ag fibers as alternative electrodes for flexible CIGS solar cells.

We explore the feasibility of Ag fiber meshes as electron transport layer for high-efficiency flexible Cu(In,Ga)Se (CIGS) solar cells. Woven meshes of Ag fibers after UV illumination and millisecond flash-lamp treatment results in a sheet resistance of 17 Ω/sq and a visible transmittance above 85%. Conductive Ag meshes are integrated into flexible CIGS cells as transparent conductive electrode (TCE) alone or together with layers of Al-doped ZnO (AZO) with various thickness of 0…900 nm.