NTU and LANL Develop a New Approach for Fabricating High-performance and Robust Perovskite Solar Modules
臺大跨國研究團隊突破傳統製程瓶頸
開發高穩定性鈣鈦礦太陽能電池模組
The international team composed of researchers from National Taiwan University (NTU) and Los Alamos National Laboratory (LANL) and led by Prof. Leeyih Wang of the Center for Condensed Matter Sciences, NTU developed a new synthetic route to tackle the bottleneck of preparing large-scale and high-quality organic-inorganic hybrid halide perovskite by the traditional one-step solution method. This facile approach enables the fabrication of robust and highly efficient perovskite solar modules. These results were recently published in Joule, a renowned journal in the field of energy research.
In the past decade, unprecedented progress has been made in pursuing high-efficiency perovskite solar cells. A single-junction perovskite cell has reached an outstanding power conversion efficiency (PCE) of 25.5%, and it has recently been picked up by industries for potential commercialization. However, two main barriers still exist for commercializing this technology: 1) the lack of low-cost, scalable fabrication in module scale and 2) poor device’s operational lifetimes. Among various fabrication methods, the one-step anti-solvent deposition process is preferred because it is a simple, cost-friendly route and is potentially compatible to industry relevant procedures. Nevertheless, the current reported methods have very narrow processing windows; the anti-solvent processing time must be strictly controlled within a few seconds after spin coating, which otherwise does not yield high-quality perovskite layer. This also results in large variations in device performances. Additionally, the perovskite cell’s lifetimes have been shown to be closely related to the quality of the perovskite layer. Therefore, to truly implement the perovskite photovoltaic technology in the market, a scalable fabrication approach yielding high-quality perovskite layer over module scale with long lifetime is urgently needed.
This study introduced sulfolane as an additive in the perovskite precursor to convert perovskite phase via a new reaction route, providing large degree of flexibilities to process reproducible and large-area perovskite layers with high uniformities. The key concept lies in building intermolecular hydrogen-bonding forces between sulfolane and methylammonium iodide, which slows down the nucleation and crystallization process, significantly extending the processing window from 9 to 90 seconds. As a result, the champion perovskite devices fabricated with sulfolane as additive exhibited PCEs of 19.39% for small-area (0.09 cm2) and 17.39% for large-area (1 cm2). Further, two mini-modules, 15.84 cm2 active area (5 cm by 5 cm) and 36.6 cm2 active area (7 cm by 7 cm) with record PCEs of 17.58% and 16.06%, respectively, were demonstrated. More importantly, the encapsulated mini-module retained about 90% of the initial performance after operating under 1-sun irradiation for 250 hours at 50oC.
Prof. Leeyih Wang and Dr. Wanyi Nie, the principal investigator of the LANL group, pointed out that broadening the processing window in the antisolvent route is essential in transferring the process to industrial production for perovskites module fabrication. It allows the flexibility in up-scale process development without sacrificing the device performance. The large-scale production can also be benefited from the widen time window for better tolerance towards manufacturing errors and environmental variations. This work paves the way for low-cost, high-throughput commercial-scale production of large-scale solar modules in the near future.
A photo of perovskite solar module and its operational stability.
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