Light-emitting electrochemical cells (LECs) can be fabricated as single emissive organic/salt-layer sandwiched between two electrodes, offering cost-effective lighting applications. The ideal device situation during operation is considered to be a p-i-n junction with doped regions at the electrodes which facilitate balanced hole and electron injection. Here, we first introduce a method to determine the center of the intrinsic region in sandwich LECs that is based on spectral photocurrent response measurements combined with optical modelling. Together with capacitance measurements, this yields a detailed picture of the evolution of the p-i-n structure. Secondly, the emission zone (EZ) is determined by simulating experimentally determined angle-dependent emission spectra. The comparison between EZ and p-i-n structure reveals sufficient agreement, suggesting that both methods can render independent insights into the device situation of a sandwich-type LEC., Presenter: Sandra Jenatsch