On February 27, Science published online the latest research results of Professor Wang Zhiping, School of Physical Science and Technology, Wuhan University, in the field of high-efficiency and stable perovskite solar cells.
This paper proposes an " atomic-scale interface bonding " technology, which uses atomic layer deposition process to introduce a controllable hafnium oxide (HfOx) intermediate layer into the key interface of the cell to stabilize the hole and electron transport interface synchronously from the atomic scale. It has successfully solved the problem that the efficiency and stability of perovskite solar cells, which have been restricting the development of perovskite solar cells for a long time, are difficult to improve synergistically.
The paper is titled "Hafnium oxide interface stabilization for efficient," Photothermally stable perovskite solar cells " (Hafnium Oxide Interface-Stabilized Strategies for Efficient, Photothermally Stable Perovskite Solar Cells). Yang yuanhang, a postdoctoral student at the School of Physical Science and Technology of Wuhan University, and Cheng Siyang, a doctoral student, are the first co-authors, Wang Zhiping is the corresponding author, and Wuhan University is the first signatory.
To realize the efficient and stable operation of optoelectronic devices, the key is to build a solid and reliable charge transfer interface. At present, high-performance perovskite batteries generally use organic molecular layers for interface modification, but these materials have insufficient stability under continuous light and high temperature environment, which easily leads to performance degradation and restricts the practical application life of devices.
▲ Multifunctional Hafnium Oxide-modified Perovskite Solar Cells and Their Excellent Stability
In response to this challenge, the atomic-scale interface bonding technology developed by the research group used the atomic layer deposition process to prepare the annealed n-type HfOx intermediate layer at the interface of the hole transport layer. The layer is rich in hydroxyl groups and shows Lewis acidity, and can form a tridentate coordination structure with higher strength with self-assembled molecules, so that the firm bonding of interface molecules is realized at the atomic scale, and the thermal stability and mechanical adhesion of the interface are significantly improved. On the side of the electron transport layer, the p-type HfOx intermediate layer anchors the passivation molecules through strong Hf · · · F bonding, which effectively inhibits their desorption at high temperature and blocks the migration of iodide ions to the metal electrode, thus delaying the decline of device performance from the source. The p-i-n perovskite solar cell
based on this technology has achieved a power conversion efficiency of 27.1% (the third party certification efficiency is 26.6%). After running for more than 5000 hours at 85 ° C and under the condition of continuous sunshine, it can still maintain the performance of more than 90% of the initial efficiency. The high temperature operating lifetime (T90) is 25 times that of the control device. This work not only achieves a double breakthrough in efficiency and stability, but also reveals the multiple cooperative stabilization mechanism of atomic-level precise interface bonding, charge distribution regulation and ion migration inhibition through inorganic oxide interlayer. The atomic layer deposition technology used in this technology route has strong compatibility with large area production process, which provides a key interface solution for promoting the industrial application of perovskite photovoltaic technology .
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