Aluminium metallisation for interdigitated back contact silicon heterojunction solar cells

Back contact silicon heterojunction solar cells with an efficiency of 22 were manufactured, featuring a simple aluminium metallisation directly on the doped amorphous silicon films. Both the open circuit voltage and the fill factor heavily depend on the parameters of the annealing step after aluminium layer deposition. Using numerical device simulations and in accordance with the literature, we demonstrate that the changes in solar cell parameters with annealing can be explained by the formation of an aluminium silicide layer at temperatures as low as 150 C, improving the contact resistance and thus enhancing the fill factor. Further annealing at higher temperatures initialises the crystallisation of the amorphous silicon layers, yielding even lower contact resistances, but also introduces more defects, diminishing the open circuit voltag

Basic study on the influence of glass composition and aluminum content on the Ag/Al paste contact formation to boron emitters

In this study, the contact formation of aluminum containing silver metallization pastes for boron emitters was investigated. Model pastes with varied glass composition (PbO-containing and PbO-free) and Al content were prepared. It was found, that glass viscosity as well as Al content have a strong influence on densification behavior of the pastes. The most significant effect of the aluminum addition is the change of the thermodynamic conditions in the system silver-glass-silicon. For investigations of the contact formation an in-situ-contact resistance measurement was performed. The interface morphology of the pastes in dependence on the firing temperature was investigated by means of cross section samples in SEM and EDX. Finally, n-type Si solar cells were electrically characterized and the IV-data were correlated to the interface morphology. (C) 2015 The Authors. Published by Elsevier Ltd

Monolithic Perovskite Silicon Tandem Solar Cells Fabricated Using Industrial p Type Polycrystalline Silicon on Oxide Passivated Emitter and Rear Cell Silicon Bottom Cell Technology

Combining a perovskite top cell with a conventional passivated emitter and rear cell PERC silicon bottom cell in a monolithically integrated tandem device is an economically attractive solution to boost the power conversion efficiency PCE of silicon single junction technology. Proof of concept perovskite silicon tandem solar cells using high temperature stable bottom cells featuring a polycrystalline silicon on oxide POLO front junction and a PERC type passivated rear side with local aluminum p contacts are reported. For this PERC POLO cell, a process flow that is compatible with industrial, mainstream PERC technology is implemented. Top and bottom cells are connected via a tin doped indium oxide recombination layer. The recombination layer formation on the POLO front junction of the bottom cell is optimized by postdeposition annealing and mitigation of sputter damage. The perovskite top cell is monolithically integrated in a p amp; 8722;i amp; 8722;n junction device architecture. Proof of concept tandem cells demonstrate a PCE of up to 21.3 . Based on the experimental findings and supporting optical simulations, major performance enhancements by process and layer optimization are identified and a PCE potential of 29.5 for these perovskite silicon tandem solar cells with PERC like bottom cell technology is estimate