Efficient Inverted Perovskite Solar Cells with a Fill Factor Over 86% via Surface Modification of the Nickel Oxide Hole Contact

Abstract

The poor interface quality between nickel oxide (NiO x ) and halide perovskites limits the performance and stability of NiO x -based perovskite solar cells (PSCs). Here a reactive surface modification approach based on the in situ decomposition of urea on the NiO x surface is reported. The pyrolysis of urea can reduce the high-valence state of nickel and replace the adsorbed hydroxyl group with isocyanate. Combining theoretical and experimental analyses, the treated NiO x films present suppressed surface states and improved transport energy level alignment with the halide perovskite absorber. With this strategy, NiO x -based PSCs achieve a champion power conversion efficiency (PCE) of 23.61% and a fill factor of over 86%. The device's efficiency remains above 90% after 2000 h of thermal aging at 85 °C. Furthermore, perovskite solar modules achieve PCE values of 18.97% and 17.18% for areas of 16 and 196 cm 2 , respectively.

Seed‐Assisted Cu‐Doped Chemical Bath Deposition for Preparing High‐Quality NiOx Hole‐Transport Layers in Perovskite Solar Cells

“…The valence band maximum of the SCBD Cu:NiO x film (−5.31 eV) is closer to that of perovskite (−5.44 eV) than the valence band maximums of CBD NiO x (−5.11 eV) and SCBD NiO x (−5.15 eV) films. [ 36 ] This is beneficial for hole transport and results in less energy loss. [ 37 ] Moreover, the SCBD Cu:NiO x film displayed an increase in the work function combined with enhanced conductivity, facilitating better charge transfer and extraction (Figure S12, Supporting Information).…”

“…The time‐resolved photoluminescence (TRPL) attenuation curve (Figure 3e) was calculated using a dual exponential attenuation model ( Y = A 1 exp( −t / τ 1 ) + A 2 exp( −t / τ 2 )), where τ 1 and τ 2 denote the fast and slow decay time constants, which are related to the radiative and trap‐assisted nonradiative recombination processes, respectively. [ 36 ] The fitting results in Table S3, Supporting Information, show that the perovskite exhibited a shorter carrier recombination lifetime on NiO x films prepared in different ways than the control sample. The pronounced fluorescence quenching observed in both the PL and TRPL spectra provides confirmation of the augmented hole injection in the SCBD Cu:NiO x film.…”

Buried Interface Passivation: A Key Strategy to Breakthrough the Efficiency of Perovskite Photovoltaics

“…[83] Li et al ameliorated the quality of the NiO x /perovskite interface by the decomposition of urea on NiO x , and it eventually inhibits the production of defects at the buried interface. [84] Similar to formamidine acetate, amino group and carboxyl groups contained in amino acids can act simultaneously to promote efficient and stable solar cells. As early as 2015, Zuo et al proposed to use 3-aminopropanioc acid (C3-SAM) to modify the buried interface.…”

Phase-Engineering of Layered Nickel Hydroxide for Synthesizing High-Quality NiOx Nanocrystals for Efficient Inverted Flexible Perovskite Solar Cells

“…One is organic functional materials, such as poly [bis (4-phenyl) (2,4,6-trimethylphenyl)-amine] (PTAA), poly­(3,4-ethylene dioxythiophene)–polystyrene sulfonate (PEDOT: PSS), polythiophene, and so on. ,− Although these organic functional materials have been successfully applied, they suffer from long-term stability, high cost, and batch-to-batch reproducibility. The second one is inorganic semiconductor materials, such as NiO x , CuSCN, Cu 2 O, etc. − Among them, NiO x is an essential material with excellent characteristics, including low cost, diverse preparation methods, and excellent thermal stability. ,,− More importantly, it has an ideal energetic alignment with perovskite materials. Thus it has become a famous star in the field of inverted PSCs in recent years.…”