Perovskite Solar Cells Using Surface‐Modified NiO_x Nanoparticles as Hole Transport Materials in n‐i‐p Configuration

Abstract

Modified NiOx nanoparticles (NPs) developed via surface engineering are applied to a hole transport layer (HTL) in n‐i‐p‐structured perovskite solar cells (PSCs). Hexanoic acid (HA) as a surfactant improves the dispersibility of NiOx NPs in chlorobenzene (CB). The conductivity of the NiOx‐HA film is 1.20×10−5S cm−1, which is superior to that of 2,2′,7,7′‐tetrakis(N,N‐di‐p‐methoxyphenyl‐amine)‐9,9′‐spirobifluorene (spiro‐OMeTAD) with dopants. The NiOx‐HA film shows better hole extraction properties compared with the pristine NiOx film. The NiOx‐HA NPs form closely packed and pinhole‐free films, leading to improved device performance with a power conversion efficiency from 5.5% to 13.1%.

Perspective on Predominant Metal Oxide Charge Transporting Materials for High-Performance Perovskite Solar Cells

“…The larger V bi of devices enables PSCs to have a stronger ability to separate charges and transport and collect photo-generated carriers, yielding a higher V OC . A variety of research works have demonstrated that minimizing the interfacial charge recombination between CTL and perovskite layer can effectively enhance the V OC of PSCs (Jung et al, 2019;Kaneko et al, 2019;Aidarkhanov et al, 2020). Carrier mobility is another critical factor affecting the charge transport properties.…”

Coordination Strategy Driving the Formation of Compact CuSCN Hole‐Transporting Layers for Efficient Perovskite Solar Cells

“…[ 18–21 ] For example, p‐type metal oxides thin films derived from high‐temperature hydrolysis and annealing have been introduced in inverted planar PSCs for achieving high device performance. [ 22–26 ] Much efforts have been made to improve hole mobility, suppress the surface defects exist in the metal oxide, [ 27–30 ] and develop low temperature processable candidates and preparation method. [ 31–33 ]…”

Tailoring of Ligand‐Off Nanoparticles Inks for Thin p‐Type Oxide Overlayers Formation with Maintaining Intact Halide Perovskite

“…One strategy that is attracting attention is a method of manufacturing a dense oxide thin film at low temperature by a solution process, using ink in which oxide nanoparticles (NPs) having high crystallinity are well dispersed. [ 10,13,14,19 ] For this, the oxide HTM ink solution should include highly dispersed metal oxide with proper electrical properties, and non‐polar solvents, such as chlorobenzene, toluene, and chloroform, to minimize the damage to the perovskite layer during the solution deposition process. However, most metal oxides present a radically hydrophilic surface, which restricts them to dispersing non‐polar solvents.…”

“…[ 14 ] To overcome those issues, hydrophobic ligand agents for capping the inorganic NPs have been utilized to improve the dispersibility in non‐polar solvents. [ 14,19 ] But it is well known that due to their insulating properties, capping agents with long carbon chain groups interfere with charge transport and transfer. [ 10,20 ] For example, the NiO‐based HPSCs with ligand agent showed a PCE of 12.7% with a very lower fill factor ( FF ).…”