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Researchers in Singapore have built an inverted perovskite photovoltaic device with an interlayer of p-type antimony-doped tin oxides (ATOx) that reduces the efficiency disparity between small and large surface area perovskite cells. According to their conclusions, ATOx can easily replace the nickel oxides (NiOx) commonly used as a hole transport material.
An international research group led by the National University of Singapore (NSU) has fabricated an inverted perovskite solar cell by placing p-type antimony-doped tin oxides (ATOx) combined with methyl-substituted carbazole (Me-4PACz) as an interlayer between the perovskite absorber and the hole transport layer (HTL).
“ATOx is robust and capable of avoiding the typical interfacial deprotonation reactions observed at the nickel oxide (NiOx)/perovskite interface, thus forming a chemically stable interface with the perovskite,” Hou Yi, author, told pv magazine corresponding to the investigation. “ATOx effectively suppresses non-radiative recombination and increases the carrier lifetime in the perovskite. Furthermore, it improves carrier transport at the ATOx/perovskite interface due to its superior conductivity.”
Inverted perovskite cells have a device structure known as a “pin,” in which the p-hole-selective contact is at the bottom of the intrinsic perovskite layer i with the electron transport layer n on top. Conventional halide perovskite cells have the same structure but inverted, a “nip” arrangement. In the pin architecture, the solar cell is illuminated through the electron transport layer (ETL) side; In the conventional nip structure, it is illuminated through the surface of the hole transport layer (HTL).
The scientists constructed the cell with an indium tin oxide (ITO) substrate, a Me-4PACz HTL, the ATOx interlayer, the perovskite absorber, a bathocuproin (BCP) buffer layer, and a silver metal contact. (Ag). The ATOx nanoparticles used in the cell had a crystal size of about 10 nm and the resulting ATOx layer had a thickness of about 20 nm.
The group highlighted that ATOx showed a higher transmittance from 300 nm to 900 nm and an optical bandgap of 4.46 eV, close to that of the most used compound in HTL, nickel(II) oxide (NiOx). “Kelvin probe force microscopy (KPFM) measurements reveal that both Me-4PACz-modified ATOx and NiOx share the same work function,” they explained, referring to a reference interlayer they developed for a reference cell. .
Tested under standard lighting conditions, the solar cell achieved a power conversion efficiency of 25.7% for an area of ??0.05 cm2 and 24.6% for an area of ??1 cm2. For both devices, the certified steady-state efficiency was 24.8% and 24.0%, respectively. These values ??were significantly higher than those achieved by the NiOx-based reference cell.
The ATOx-based inverted devices were also able to retain around 90% of the initial efficiency for 2,000 h and around 93% for 500 h.
“Devices using ATOx effectively reduce the efficiency disparity between small- and large-area perovskite cells,” Yi says. “ATOx offers a combination of high efficiency, stability and scalability as a hole transport material, superior to the commonly used NiOx.”
The research group described the novel cell concept in the study “ Enhancing the efficiency and longevity of inverted perovskite solar cells with antimony-doped tin oxides. ” with antimony), published in nature energy . |
