Trichromatic fluorescent diatomite-based carbon dot composites for dual-mode high-resolution imaging of latent fingerprints

Fingerprints are recognized as one of the most reliable biometric features in forensic science. Carbon dots (CDs), a zero-dimensional carbon material, have emerged as an ideal candidate for fluorescence imaging of latent fingerprints, paving the way for a new era of fingerprint nano development technique.

A team of forensic investigators led by Dawu Li from Criminal Investigation Police University of China in Shenyang, Liaoning, China recently explored the promising “luminescence by design” strategy for achieving tunable optical properties of CDs. Customized fluorescence of CDs has potential applications in high-resolution fingerprint development as it enables ambient light and substrate surface interference suppression. Current research shows that the choice of carbon source significantly influences the structural and optical properties of CDs, often closely resembling the inherent characteristics of the precursors. Therefore, the selection of precursors is crucial for synthesizing CDs with specific attributes.

The team published their article in Nano Research on November 3, 2025.

“In this study, we reported a novel dual-mode fingerprint imaging strategy based on fluorescent diatomite-based CD composites and tunable multicolor post-processing techniques. Experimental and theoretical results demonstrated that the high photostability and photobleaching resistance of the synthesized Dye-CDs were derived from hydrogen-bond-mediated enhanced networks between the carbonaceous matrix and dye-related functional groups and fragments serving as CDs’ luminescence center. By combining multi-color-emitting CDs with diatomite, the resulting Dye-CDs/Diatomite composites exhibited high selectivity and contrast in daylight and fluorescence fingerprint visualization,” said Dawu Li, senior author of the paper, associate professor in the College of Forensic Science at Criminal Investigation Police University of China.

CDs with tunable optical properties and high photostability offers unique advantages for fluorescence imaging of latent fingerprints due to their facile synthesis, high biocompatibility, and surface functionalities.

The research team expects the study to spur development of new carbon dot-based developing agents designed for high-performance fluorescence nano development of latent fingerprints. “Carbon dot-based developing agents for fingerprint fluorescence imaging are expected to become more diverse and practical in the coming years,” said Dawu Li.

Other contributors include Jiujiang Wang and Xiaosen Lv from the College of Forensic Science at Criminal Investigation Police University of China; Jianghua Zhang from the College of Anti-Drug and Public Security at Criminal Investigation Police University of China; Zijian Gao from the Department of Information Systems, Business Statistics and Operations Management at the Hong Kong University of Science and Technology in Hong Kong, China; and Jinke Han from the Questrom School of Business at Boston University in Boston, MA, USA.

This study was supported by the Key Laboratory of Impression Evidence Examination and Identification Technology, Criminal Investigation Police University of China, Ministry of Public Security, People’ s Republic of China (2018HJKF12); the Natural Science Foundation of Liaoning Province (No. 2023-BS-081); and the Foundation of Education Department of Liaoning Province (LJKMZ20221366, LJKQZ20222296).

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.