Prof. LI Gang, Chair Professor of Energy Conversion Technology and Sir Sze-yuen Chung Endowed Professor in Renewable Energy of the PolyU Department of Electrical and Electronic Engineering, and his research team have published a paper titled “Two-step crystallisation modulated through acenaphthene enabling 21% binary organic solar cells and 83.2% fill factor” in Nature Energy.
The crystallisation dynamics of non-fullerene acceptors influences the morphology and charge dynamics of organic solar cells, ultimately determining device performance. However, optimising the molecular arrangement of donor and acceptor materials within the active layer remains a considerable challenge. In this study, the research team controlled the crystallisation kinetics of non-fullerene acceptors with a crystallisation-regulating agent, acenaphthene. Acenaphthene alters the self-organisation of acceptor molecules by inducing a two-step crystallisation process: it initially fixes the packing motif of the acceptor, and subsequently refines the crystallised framework, resulting in highly oriented acceptors within the active layer.
This approach establishes multiple charge-transport pathways, thereby enhancing the charge-transport properties of the device. As a result, power conversion efficiencies of 20.9% (20.4% certified) and 21% (20.5% certified) were achieved in D18/L8-BO and PM1/L8-BO-X binary organic solar cells, respectively, with a maximum fill factor of 83.2% (82.2% certified). These findings represent a significant advancement in the development of high-performance organic solar cells.
This innovative strategy paves the way for further breakthroughs in the efficiency and commercial viability of next-generation organic photovoltaic technologies.
Read the full paper:https://www.nature.com/articles/s41560-025-01862-1
香港理工大學電機及電子工程學系能源轉換技術講座教授、鍾士元爵士可再生能源教授李剛教授及其研究團隊，於《Nature Energy》發表了題為「Two-step crystallisation modulated through acenaphthene enabling 21% binary organic solar cells and 83.2% fill factor」（通過苊調控兩步結晶，實現21%雙面有機太陽能電池及83.2%填充因子）的研究論文。
非富勒烯受體的結晶動力學會影響有機太陽能電池活性層形貌及電荷傳輸特性，進而決定器件的光電轉換效率。然而，如何優化供體與受體材料在活性層中的分子排列，仍然是一項重大挑戰。在本研究中，團隊利用結晶調控劑「苊」，精確控制非富勒烯受體的結晶動力學。苊透過誘導兩步驟結晶過程，改變受體分子的自組裝行為：苊分子首先固定受體的堆積模式，隨後進一步令結晶框架更精細，最終在活性層中形成長程有序的受體結構。
此創新方法通過構建了多重電荷傳輸通道，顯著提升器件的電荷傳輸效率。研究結果顯示，在D18/L8-BO及PM1/L8-BO-X雙元有機太陽能電池中，分別實現了20.9%（認證值20.4%）及21%（認證值20.5%）的光電轉換效率，最高填充因子達83.2%（認證值82.2%）。這些成果標誌著高性能有機太陽能電池發展的重要突破。
這項創新策略為新一代有機光伏技術的效率提升及商業化應用奠定了堅實基礎，並開啟了更多技術突破的可能性。
閱讀論文全文：https://www.nature.com/articles/s41560-025-01862-1
