The First Glued Tandem Solar Cell Using a ZnO Based Adhesive

By adjusting the process flow of a newly developed transparent conductive adhesive (TCA), the first mechanically stable interconnection of a glued III-V on Si tandem solar cell was established utilizing a ZnO-based adhesive. The measured $V_{OC}$ of 1691 mV is a first proof of concept for the developed TCA. The functionality of the two sub-cells in the tandem device was proven by external quantum efficiency (EQE) measurements. The reflectance at the bond interface of such a glued tandem solar cell remains the limiting factor. In order to reduce the optical losses, the effect of a textured silicon surface was investigated in test structures, which indeed showed reduced reflectance. Furthermore, this textured test structure showed an improved connecting resistivity as low as $83\ \mathrm{m}\Omega\text{cm}^{2}$ .