P-type a-SiOx:H as a Hole Transport Layer in p-i-n Perovskite Solar Cells

Abstract

P-type a-SiOx:H (p-a-SiOx:H) was investigated as a hole transport layer (HTL) in perovskite solar cells (PSCs). First p-a-SiOx:H layers were fabricated and characterised then full cells were fabricated and their IV-characteristics studied. It was discovered that a large barrier is present preventing efficient extraction of the holes from the perovskite into the HTL, resulting in the cells possessing very low short-circuit currents, fill factors and efficiencies. Different combinations of materials, and a UV + ozone treatment, were tested to investigate the cause of this barrier. It is thought that a number of factors could be responsible, namely, poor wetting of the perovskite solution on p-a-SiOx:H leading to poor microscopic contact between the two materials, non-optimal valence band alignment of the perovskite and p-a-SiOx:H, and/or low conductivity of p-a-SiOx:H. At the current status and without further investigation, it cannot be concluded whether p-a-SiOx:H can be used as a HTL in perovskite solar cells.