Nickel Oxide/Cobalt Phthalocyanine as a Hole Transport Bilayer for Efficient and Stable Inverted Perovskite Solar Cells
Meiirkhan Beisembekov, А.К. Aimukhanov, S.K. Tazhibayev, D.R. Abeuov, А.К. Zeinidenov
Abstract
Abstract This study demonstrates that the use of bilayer films based on nickel oxide (NiO x ;) and cobalt phthalocyanine (CoPc) represents a promising hole transport layer (HTLs) for inverted perovskite solar cells (PSCs). NiO x ; films are fabricated using the spin‐coating method from a sol–gel solution. Films (CoPc evap ) and nanowires (CoPc nws ) on the NiO x ; surface are produced by thermal sputtering and physical gradient‐temperature vapor deposition. It is demonstrated that PSCs with a NiO x ; layer exhibit a power conversion efficiency (PCE) of only 18,1%. The incorporation of a CoPc evap intermediate layer between NiO x ; and the perovskite increases the PCE to 19.1%. The highest PCE, reaching 20.7%, is achieved with a bilayer HTLs based on NiO x ;/CoPc nws . Analysis of the PSC impedance spectra shows that the CoPc nws intermediate layer reduces the HTLs resistance and increases the recombination resistance at the perovskite/HTLs interface, which extends the effective lifetime of charge carriers. The stability of NiO x ;‐based PSCs is 48%, while PSCs with bilayer HTLs based on NiO x ;/CoPc nws and NiO x ;/CoPc evap exhibits higher stability of 71% and 90% over 600 hours. The results demonstrated that solar cells based on NiO x ;/CoPc inhibit the perovskite degradation process and reduce charge recombination, thereby improving the performance and stability of the inverted PSCs.