Low-cost Narrow-Bandgap Organic Semiconductor for Efficient Photovoltaic and Photodetection Applications
Ni Yang, Yong Cui, Wei Fu, Xueliang Ma, Tao Zhang, Wenxuan Wang, Yang Xiao, Zhihao Chen, Qian Kang, Guangzheng Zuo, Jianhui Hou
Abstract
Narrow-bandgap semiconductors are crucial for advancing optoelectronic devices such as photodetectors and photovoltaic cells. However, the high cost of crystalline inorganic semiconductors, along with fabrication complexities, necessitate alternative, cost-effective materials. In contrast, organic semiconductors give the advantages of tunable absorption spectra and compatibility with flexible substrates. In this work, we address the need for low-cost, high-performance narrow-bandgap materials by designing a new nonfused nonfullerene acceptor, 4T-11. This molecule features enhanced intramolecular charge transfer due to the introduction of electron-donating alkoxy substituents, leading to a significant reduced optical bandgap of 1.22 eV. The 4T-11-based organic photovoltaic device achieved an outstanding power conversion efficiency of 14.3%, the highest value for nonfullerene acceptors with an absorption onset exceeding 1000 nm. Furthermore, the 4T-11-based photodetector demonstrated exceptional responsivity, surpassing 10 13 Jones across the 450–1000 nm wavelength range. This study provides valuable guidance into the molecular design of cost-effective narrow-bandgap organic semiconductors for next-generation optoelectronics.