CM6@Zn-MOF奈米片的人工光補系統， 大幅提升光電效能

Abstract

摘 要 二維鋅金屬有機框架（Zn-MOF），可以應用在人工光能收集系統上，也就是模仿植物行光合作用來收集光能的技術。設計了一種結構特殊的Zn-MOF，利用了兩種有機配體（H₂mpda 和 tib）去合成這個材料，然後用原子力顯微鏡（AFM）確認這個材料的厚度大概只有5奈米。用超音波剝離技術，成功做出表面積很大的Zn-MOF奈米片。這些奈米片的特點是它們的螢光發射光譜跟CM6的紫外-可見光吸收光譜重疊，因此可以進行一種叫做螢光共振能量轉移（FRET）的機制，這個機制可以讓能量從一個分子傳遞到另一個分子，應用在人工光能收集系統（ALHS）上非常有潛力。跟傳統單晶的Zn-MOF相比，這種新型的材料CM6@Zn-MOF(2)有更大的比表面積（41 m²/g）、更高的量子產率（約30.56%）、更窄的能隙（2.87 eV），而且吸收光的範圍可以延伸到可見光區的綠光。更重要的是，它有很好的光電表現，像是開關電流比（21倍）和光電流密度都比純Zn-MOF還要高。這篇研究提出了一種新材料，不但可以有效收集光能、轉換光成電，還為未來在光學裝置和電化學材料的應用上，打下了理論基礎。

Abstract A two-dimensional zinc metal-organic framework (Zn-MOF) can be applied in artificial light-harvesting systems, which mimic the photosynthesis of plants to collect solar energy. A specially structured Zn-MOF was designed using two organic ligands (H₂mpda and tib) to synthesize this material. Atomic force microscopy (AFM) confirmed that the thickness of the material is approximately 5 nanometers. Using ultrasonic exfoliation, Zn-MOF nanosheets with a large surface area were successfully produced. These nanosheets are characterized by the overlap between their fluorescence emission spectrum and the UV-visible absorption spectrum of CM6, enabling a mechanism known as Förster Resonance Energy Transfer (FRET). This mechanism allows energy to be transferred from one molecule to another, making it highly promising for applications in artificial light-harvesting systems (ALHS). Compared with traditional single-crystal Zn-MOFs, this novel material, CM6@Zn-MOF(2), possesses a larger specific surface area (41 m²/g), higher quantum yield (approximately 30.56%), narrower band gap (2.87 eV), and its light absorption range extends into the visible green region. More importantly, it exhibits excellent photoelectric performance, such as a higher on/off current ratio (21 times) and greater photocurrent density than pure Zn-MOF. This study introduces a new material that not only effectively captures light energy and converts it into electricity but also lays a theoretical foundation for future applications in optical devices and electrochemical materials.