High-Efficiency and Stable Inverted Planar Perovskite Solar Cells with Pulsed Laser Deposited Cu-Doped NiO_x Hole-Transport Layers

High-quality hole-transport layers (HTLs) with excellent optical and electrical properties play a significant role in achieving high-efficient and stable inverted planar perovskite solar cells (PSCs). In this work, the optoelectronic properties of Cu-doped NiOx (Cu:NiOx) films and the photovoltaic performance of PSCs with Cu:NiOx HTLs were systematically studied. The Cu-doped NiOx with different doping concentrations was achieved by a high-temperature solid-state reaction, and Cu:NiOx films were prepared by pulsed laser deposition (PLD). Cu+ ion dopants not only occupy the Ni vacancy sites to improve the crystallization quality and increase the hole mobility, but also substitute lattice Ni2+ sites and act as acceptors to enhance the hole concentration. As compared to the undoped NiOx films, the Cu:NiOx films exhibit a higher electrical conductivity with a faster charge transportation and extraction for PSCs. By employing the prepared Cu:NiOx films as HTLs for the PSCs, a high photocurrent density of 23.17 mA/cm2 and a high power conversion efficiency of 20.41% are obtained, which are superior to those with physical vapor deposited NiOx HTLs. Meanwhile, the PSC devices show a negligible hysteresis behavior and a long-term air-stability, even without any encapsulation. The results demonstrate that pulsed laser deposited Cu-doped NiOx film is a promising HTL for realizing high-performance and air-stable PSCs.