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Designed to be produced at a substantially lower cost than conventional perovskite solar cells based on metal contacts, the new cell is capable of achieving a bifaciality factor greater than 80% and a power generation density greater than 36%.
Researchers at the University of Surrey (United Kingdom) have manufactured a flexible bifacial solar cell that uses single-walled carbon nanotubes (SWCNT) as front and back electrodes.
Traditional metal grid contacts used as electrodes in solar cells are capable of providing transparency, but also require high doping of the cell surface layer to provide efficient photocurrent collection. Intensive doping and deposition are energy-intensive industrial processes, thereby raising the production costs of similar solar cells. SWCNTs represent an alternative, as they are said to combine optoelectronic properties, flexibility, chemical stability, and simple transfer protocols to cover large surfaces.
“For optimal bifacial applications, both front and back electrodes must be optically transparent, chemically stable, and compatible with adjacent layers,” the scientists state. “Their exceptional optical property makes SWCNT films well suited as front electrodes for optoelectronic applications spanning a broad spectrum of wavelengths.”
The researchers used the floating catalyst chemical vapor deposition (FCCVD) method to prepare SWCNT films with an optical transmittance of about 95% at a wavelength of 550 nm, which exceeded that of common carbon oxide substrates. indium and tin (ITO).
The research group constructed the bifacial solar cell with a glass substrate, a SWCNT electrode, a copper-doped nickel oxide (Cu:NiOx) hole transport layer (HTL), a perovskite absorber, a electron transport (ETL) based on tin(IV) oxide (SnO2), a layer of phenyl-C61-butyric acid methyl ester (PCBM) and another SWCNT electrode.
Tested under standard lighting conditions, the flexible device achieved a front-end power conversion efficiency of 17.1% and a high power-to-weight value of 73.75 W/g. It also showed potential to achieve a bifaciality factor greater than 98% and a power generation density greater than 36%.
“SWCNTs are flexible and mechanically robust, allowing them to withstand repeated bending cycles,” the researchers explain. “These characteristics make SWCNTs suitable for flexible perovskite solar cells and enable new visions for the development of bifacial devices.”
The scientists claim that the new cell based exclusively on carbon electrodes can be manufactured with material costs 70% lower than those of monofacial perovskite cells that use ITO or silver (Ag) for the electrodes. “The economic advantage is even greater when equipment costs are taken into account, since devices based exclusively on carbon electrodes eliminate the need for expensive radio frequency (RF) sputtering processes or thermal evaporation for ITO or metallic electrodes. ", they add.
The novel cell concept is presented in the study “ High-performance bifacial perovskite solar cells enabled by single-walled carbon nanotubes,” published in nature energy . |
