Accelerating photocarrier dynamics by constructing 2D-3D homojunction toward boosting self-powered UV photodetection

The development of self-powered ultraviolet (UV) photodetectors with high selectivity, fast response, and strong environmental adaptability is crucial for advanced optoelectronic applications, particularly in fields such as UV communication, environmental monitoring, and wearable sensing. A research team led by Professor Wei Feng from College of Chemistry, Chemical Engineering and Resource Utilization at Northeast Forestry University has recently proposed an innovative strategy to enhance photocarrier dynamics by constructing an In₂O₃ homojunction, achieving high-performance and fast UV photodetection.

In their study published in Nano Research, the researchers fabricated a self-powered UV photodetector by creating a planar homojunction based on 2D In₂O₃ nanosheets (NS) and 3D In₂O₃ microcubes (MC), and the former not only shows an enlarged bandgap due to the quantum confinement effect but also effectively upshifts the conductive band and Fermi level stemming from the oxygen vacancy demonstrated by the theoretical simulation and experimental results. The photogenerated carrier dynamic of In₂O₃ photoanodes is boosted by the 2D-3D homojunction with a built-in electric field and more electrochemically active sites, leading to higher photogenerated carrier separation efficiency, faster interfacial charge transfer, and better self-powered capability.

The In₂O₃ 2D-3D homojunction PEC UV PDs exhibit outstanding self-powered deep-UV photoresponse at 0 V, with an ultrahigh responsivity of 316.5 mA/W for 254 nm light, a fast response speed of 15/15 ms, high detectivity of 1.12 × 10¹² Jones, and an outstanding UV-vis rejection ratio of 1507, surpassing most recorded PEC UV PDs. This work demonstrates the pivotal role of morphology-controlled homojunction in modulating photogenerated carrier dynamics and offers a new strategy for designing high-performance PEC devices.

“Our design provides a new pathway for constructing high-performance UV photodetectors by leveraging the advantages of homojunction-based energy band engineering,” said Prof. Wei Feng, senior author of the paper. “It opens promising possibilities for next-generation self-powered devices with high response and fast communication.” The study offers a general and scalable strategy for optoelectronic device engineering, emphasizing the role of oxygen vacancy and nano effect in homojunction devices. The authors anticipate their approach could be extended to other material systems and device types in the future.

Other contributors include Nana Zhang, Xinyu Gao, Zhitao Shao, Sha Zhao, Junxin Zhou, Yuan Zhang, Jiaming Zhang, Ruyu Sun, Wenhui Li, Xinghan Li from College of Chemistry, Chemical Engineering and Resource Utilization at Northeast Forestry University, China; and Zhengguang Shi, Hsu-Sheng Tsai and Pingan Hu from Harbin Institute of Technology.

This work is supported by the Natural Science Foundation of Heilongjiang Province, China (Grant No. PL2024E001).

About Nano Research

Nano Research is a peer-reviewed, open access, international and interdisciplinary research journal, sponsored by Tsinghua University and the Chinese Chemical Society, published by Tsinghua University Press on the platform SciOpen. It publishes original high-quality research and significant review articles on all aspects of nanoscience and nanotechnology, ranging from basic aspects of the science of nanoscale materials to practical applications of such materials. After 18 years of development, it has become one of the most influential academic journals in the nano field. Nano Research has published more than 1,000 papers every year from 2022, with its cumulative count surpassing 7,000 articles. In 2024 InCites Journal Citation Reports, its 2024 IF is 9.0 (8.7, 5 years), and it continues to be the Q1 area among the four subject classifications. Nano Research Award, established by Nano Research together with TUP and Springer Nature in 2013, and Nano Research Young Innovators (NR45) Awards, established by Nano Research in 2018, have become international academic awards with global influence.