Advances and Potentials of NiO_x Surface Treatments for p−i−n Perovskite Solar Cells

Abstract

The performances of perovskite solar cells (PSCs) largely depend on the perovskite compositions and the selection of electron and hole transport layers (ETLs and HTLs). The p‐type NiO x films are largely used as HTLs in p‐i‐n PSCs, thanks to their high transparency, processing versatility, cost‐effectiveness, and easy integration within tandem devices. Several studies have shown that surface modifications on NiO x films remove the surface defects, increase the NiO x conductivity, and alter the band offset, consequently improving the interfaces between NiO x films and the perovskite active layer. Indeed, besides improving the NiO x intrinsic properties, the surface treatments also lead, in many cases, to superior perovskite quality driving high photovoltaic performance.

Fully Textured, Production‐Line Compatible Monolithic Perovskite/Silicon Tandem Solar Cells Approaching 29% Efficiency

“…The energy level results were further deduced in Figure 3b, where sputtered NiO x has a valence band maximum (VBM) of −5.59 eV and a work function (WF) of −4.47 eV, agreeing well with previous reports. [ 41–43 ] After the NiO x being treated with 2PACz, its VBM shifts slightly to −5.55 eV while the WF greatly increases to −5.10 eV, energetically more aligned with the Fermi level (5.08 eV) of our wide‐bandgap perovskite. The WFs of ITO and NiO x both greatly increased after being treated with 2PACz.…”

Surface Re-Engineering of Perovskites with Buckybowls to Boost the Inverted-Type Photovoltaics

“…More encouragingly, the obtained PCE of 22.10% is one of the highest values among reported NiO x -based PSCs to date. 58 Impacts of ACIs on the Device Stability. Widely known as a knotty problem for triggering device failure, ion migration notoriously causes phase segregation and undesired chemical or physical processes in perovskite films, among which the migration of negatively charged halide ions seems to be more prevalent.…”

Crack‐Free Monolayer Graphene Interlayer for Improving Perovskite Crystallinity and Energy Level Alignment in Efficient Inverted Perovskite Solar Cells

“…[10][11][12] To date, the NiO x HTL in inverted PSC has been prepared by various methods, such as magnetron sputtering, electron beam deposition, pulsed laser deposition, and solution process. [13] Among them, the solution process to fabricate NiO x HTL has been considered a promising approach due to its simple fabrication, low cost, and high yield. However, the solution-processed NiO x HTL is subjected to the natural randomly distributed defects and intrinsic conductivity.…”