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Indian scientists built an inverted perovskite photovoltaic device that uses a self-assembled monolayer to suppress non-radiative recombination at the interface between the perovskite absorber and the hole transport layer. The cell achieved remarkable efficiency and was also able to maintain the initial efficiency rate for 3,000 h.
Researchers at the Indian Institute of Technology, Bombay, Powai Mumbai, India, have fabricated an inverted perovskite solar cell based on a hole transport layer (HTL) made of a phosphonic acid called methyl-substituted carbazole (Me-4PACz).
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 reversed: a "nip" arrangement.
In the nip architecture, the solar cell is illuminated through the electron transport layer (ETL) side; in the pin structure, it illuminates through the surface of the hole transport layer (HTL).
Dinesh Kabra, lead author of the research, told pv magazine : “Our method is excellent in ensuring that the Fermi electronic level can be tuned based on the bandgap of the absorbing layer and will therefore be very useful for cell application. “tandem solar.” “In addition, it offers the added advantage of the wettability of the perovskite halide solution to provide a compact, reproducible and scalable layer. “Which is known to be an important challenge for this technology along with stability.”
The scientists explained that the Me-4PACz HTL is a self-assembled monolayer (SAM) capable of suppressing non-radiative recombination at the interface between the perovskite absorber and the Me-4PACz layer.
The solar cell has an active area of ??0.175 cm2. It is based on a glass substrate and indium tin oxide (ITO), an interfacial layer formed by the PFN polymer, the HTL layer of Me-4PACz, the perovskite absorber, an electron transport layer (ETL) formed by phenyl-C61-butyric acid methyl ester (PCBM), a buffer layer of bathocuproine (BCP), a layer of tin(IV) oxide (SnO2), and a transparent conductive oxide film of indium zinc oxide (IZO) .
Tested under standard conditions, the cell achieved an energy conversion efficiency of 20.7%. “To the best of our knowledge, the device efficiency obtained is one of the highest values ??recorded for Me-4PACz with a triple cation perovskite composition having a bandgap of 1.6 eV,” the scientists stated, noting that the device was capable of maintaining initial efficiency for 3,000 h.
“We believe that the blend engineering of the Me-4PACz SAM with the electrolyte polymer PFN-Br will not only open new doors to address hydrophobic SAMs in efficient solution-processable photovoltaic devices, but will also allow the design of new electrolyte-based polymers and/or or small molecules that can combine with SAMs, thus cushioning a better interface,” the scientists noted.
The solar cell was presented in the study “ Resolving the Hydrophobicity of the Me-4PACz Hole Transport Layer for Inverted Perovskite Solar Cells with Efficiency >20% ”. inverted perovskite with an efficiency >20%.), published in ACS Publications . |
