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Chinese scientists have fabricated a Ruddlesden-Popper perovskite solar cell based on gamma-aminobutyric acid (GABA) as the organic spacer cation. They claim that this innovation offers higher power conversion efficiency and exceptional stability.
Scientists at Zhengzhou University, China, have designed a low-dimensional Ruddlesden-Popper perovskite (LPDR)-based solar cell that appears to have better carrier transport properties.
“Compared with normal three-dimensional perovskite solar cells, these cells are more stable,” researcher Yiqiang Zhang told pv magazine . “They are suitable for building-integrated photovoltaics (BIPV), conventional solar power, and portable devices, and have high stability.”
Ruddlesden-Popper perovskites typically have higher moisture stability and lower encapsulation costs. One of its first applications will probably be as a top layer for conventional perovskite solar cells.
The researchers used a gamma-aminobutyric acid (GABA)-based LDRP as the organic spacer cation and a type of lead halide perovskite known as methylammonium lead iodide (MAPbI3).
“The GABA-MAPbI3 film offers an enhanced carrier mobility of 1.61 cm2 V and a charge diffusion length (electrons and holes) greater than 700 nm,” they state.
The cell setup consists of an indium tin oxide (ITO) substrate, a tin(IV) oxide (SnO2) buffer layer, the 2D perovskite absorber, a spiro-OMeTAD gap-blocking layer, and a metal contact. According to the Chinese team, the use of LDPR results in an energy conversion efficiency of the cell of 18.73%, which compares to 16.14% for a reference device without the addition of GABA.
“In addition, the starting devices show extraordinary stability under continuous illumination, ambient atmosphere, 65 C, and 85% relative humidity, respectively. We speculate that GABA electrons may push excitonic states out of the band tails through hydrogen bonding interaction."
The scientists claim that the hydrogen bonding interactions between the carboxyl groups of the spacer cations of the GABA bilayer bridge the charge transfer channel while favoring optimization of the energy band structure responsible for the absorption of the light.
They describe the cell technology in Dredging the Charge- Carrier Transfer Pathway for Efficient Low-Dimensional Ruddlesden-Popper Perovskite Solar Cells. dimension), recently published in Angewandte Chemie.
“Potential production costs are comparable to normal 3D perovskite solar cells, lower than commercially available silicon cells,” Zhang concludes. |
