Review of Defect Passivation for NiO_x-Based Inverted Perovskite Solar Cells

Abstract

In recent years, organic−inorganic hybrid perovskite solar cells (PSCs) have attracted extensive attention due to their high power conversion efficiency (PCE) and simple preparation process. The selection and optimization of the hole transport layer (HTL) are very important for device performance. Compared to other HTLs, nickel oxide (NiO x ) has been widely used in PSCs due to its good chemical stability, high hole mobility, and simple preparation method. This review begins with the application of NiO x HTL in planar PSCs and systematically introduces the influence of the structure and photoelectrical properties of devices by doping and surface modification. The effects of NiO x modification on the power conversion efficiency (PCE), filling factor (FF), open-circuit voltage (V oc ), short-circuit current (J sc ), and stability of PSCs are reviewed in detail from the perspectives of energy-level matching, hole mobility, and crystallinity. Finally, the future of NiO x -based planar PSCs is discussed.

Applications of Metal Oxide Charge Transport Layers in Perovskite Solar Cells

“…The doping of Cd also lowered the VBM of NiO x , accelerated the extraction and transport of holes, and suppressed nonradiative recombination at the interface. [ 129 ] As a result, the device efficiency was improved from 18.23% to 20.47%. Al was also used to dope NiO x , which reduced the roughness of the NiO x film and enhanced the electrical conductivity.…”

Unraveling the modification effect at NiOx/perovskite interfaces for efficient and stable inverted perovskite solar cells

“…[32][33][34] The intrinsic defects (Ni vacancies) in NiO x lms are essential for hole conductivity, but they simultaneously cause the generation of defect energy levels and perovskite degradation. [35][36][37][38] Therefore, a proper modication at the NiO x /perovskite interface is necessary. Halogen-substituted benzoic acids have been reported to modify NiO x lms, which could lower charge carrier recombination and achieve stable and efficient inverted PSCs.…”

Water-Soluble Cationic Copolyacrylamides Modifying NiOx for High-Performance Inverted Perovskite Solar Cells

“…Inorganic nickel oxide (NiO X ) materials have attracted considerable interest as potential HTLs in inverted PVSCs due to their ease of synthesis, low cost, high optical transmission, high hole mobility, wide band gap, deep valence band that aligns well with those of perovskites, and excellent chemical and thermal stabilities. , Low intrinsic conductivity of the NiO X layer, a comparatively large energy level offset, and poor contact at the NiO X -perovskite interface hinder the charge transfer from the perovskite to the NiO X layer. The presence of interfacial NiO X defects can reduce the PV performance of inverted PVSCs. , …”

“…The presence of interfacial NiO X defects can reduce the PV performance of inverted PVSCs. 14,15 Modifying the NiO X film's surface morphology, energy level, and electrical properties is the current method for rectifying contact defects at the NiO X -perovskite interface. Between the NiO X and perovskite layers, numerous interfacial modifiers, such as alkali metal halides, inorganic nanoparticles, nanocarbon materials, Lewis bases, Lewis acids, organic pigments, and polymers, have been introduced.…”