17% efficiency heterostructure solar cell based on p-type crystalline silicon

In this work we describe in detail the process used to obtain high efficiency amorphous/crystalline silicon heterostructure solar cells, based on p-type crystalline silicon, typically used in cast production. The back side contact and very effective back surface field have been obtained by a screen printing process. An amorphous silicon intrinsic buffer layer and a n-type amorphous emitter have been deposited on the top of the wafer. A particular treatment has been performed on the top of the n layer in order to increase the conductance and reduce the activation energy of the layer. Finally a silver grid and an antireflection coating are deposited on the top of the device. With the aid of a numerical model, able to describe in detail the role of defect density at the heterojunction and the transport mechanism in the whole structure we analyze the photovoltaic performance. The current–voltage characteristic under AM1.5 and the quantum efficiency on 2.25 cm2 sample have been reported. An efficiency of 17% is achieved that represents the highest result obtained on heterostructure solars cell based on p-type crystalline silicon.