Ultrafast Dynamics Group
Frédéric Laquai's Group

Room-Temperature Sputtered Nanocrystalline Nickel Oxide

Room-Temperature Sputtered Nanocrystalline Nickel Oxide as Hole Transport Layer for p−i−n Perovskite Solar Cells

​Room-Temperature Sputtered Nanocrystalline Nickel Oxide as Hole Transport Layer for p−i−n Perovskite Solar Cells

​Erkan Aydin, Joel Troughton, Michele De Bastiani, Esma Ugur, Muhammad Sajjad, Areej Alzahrani, Marios Neophytou, Udo Schwingenschlögl, Frédéric Laquai, Derya Baran, and Stefaan De Wolf
ACS Appl. Energy Mater., DOI: 10.1021/acsaem.8b01263​​
Erkan Aydin, Joel Troughton, Michele De Bastiani, Esma Ugur, Muhammad Sajjad, Areej Alzahrani, Marios Neophytou, Udo Schwingenschlögl, Frédéric Laquai, Derya Baran, and Stefaan De Wolf
perovskites solar cells, room-temperature processing, sputtering, nickel oxide, conformal deposition, large area, p-i-n perovskite device configuration
2018
Nickel oxide (NiOx) is a promising hole transport layer (HTL) for perovskite solar cells (PSCs), as it combines good chemical stability, high broadband optical transparency and a high work function. Excellent power conversion efficiencies (PCE) have already been reported using solution-processed NiOx. However, solution-based techniques usually require high-temperature post-annealing to achieve the required HTL properties of NiOx, which jeopardizes its use for many applications, such as monolithic tandem solar cells. To resolve this issue, we developed room-temperature sputtered NiOx and demonstrated p−i−n PSCs with 17.6% PCE (with negligible hysteresis), which is comparable to the best PSCs using sputtered and annealed NiOx without heteroatom doping. Through detailed characterization and density functional theory (DFT) analysis, we explored the electrical and optical properties of the obtained NiOx films and find that they are strongly linked with the specific defect chemistry of this material. Finally, in view of its use in perovskite/silicon tandem solar cells, we find that direct sputtering on random-pyramid textured silicon wafers results in highly conformal NiOx films.