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Graphene quantum dots (GQDs) have received much attention due to their novel phenomena of charge transport and light absorption/emission. The optical transitions are known to be available up to ~6 eV in GQDs, especially useful for ultraviolet (UV) photodetectors (PDs). Thus, the demonstration of photodetection gain with GQDs would be the basis for a plenty of applications not only as a single-function device in detecting optical signals but also a key component in the optoelectronic integrated circuits. Here, we firstly report high-efficient photocurrent (PC) behaviors of PDs consisting of multiple-layer GQDs sandwiched between graphene sheets. High detectivity (>10(11) cm Hz(1/2)/W) and responsivity (0.2 ~ 0.5 A/W) are achieved in the broad spectral range from UV to near infrared. The observed unique PD characteristics prove to be dominated by the tunneling of charge carriers through the energy states in GQDs, based on bias-dependent variations of the band profiles, resulting in novel dark current and PC behaviors.
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http://dx.doi.org/10.1038/srep05603 | DOI Listing |
Nanoscale
September 2025
Fujian Key Laboratory of Drug Target Discovery and Structural and Functional Research, Higher Educational Key Laboratory for Nano Biomedical Technology of Fujian Province, The School of Pharmacy, Fujian Medical University, Fuzhou, Fujian 350122, People's Republic of China.
The rational design of non-precious metal catalysts as a replacement for Pd is of great importance for catalyzing various important chemical reactions. To realize this purpose, the palladium-like superatom NbN was doped into a defective graphene quantum dot (GQD) model with a double-vacancy site to design a novel single superatom catalyst, namely, NbN@GQD, based on density functional theory (DFT), and its catalytic activity for the Suzuki reaction was theoretically investigated. Our results reveal that this designed catalyst exhibits satisfactory activity with a small rate-limiting energy barrier of 25.
View Article and Find Full Text PDFACS Nano
September 2025
Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea.
Visible-light activation is highly desirable for gas sensors due to its energy-efficient operation and broad accessibility. Photocatalysis offers a promising strategy for visible-light activation; however, a limited understanding of the band engineering-mediated activation process restricts the rational design of photocatalysts for gas sensors. In this work, we systematically investigate the impact of band tuning in photocatalysts on the nitrogen dioxide (NO) sensing performance of InO-based sensors, employing graphene quantum dots (GQDs) as photosensitizers.
View Article and Find Full Text PDFPhys Chem Chem Phys
September 2025
Center of Excellence in Computational Chemistry (CECC), Department of Chemistry, Faculty of Science, Chulalongkorn University, Pathumwan, Bangkok 10330, Thailand.
We conducted a study to examine the impact of an external electric field on the curvature of metal and divalent metal ion doped 4N divacancy-defected graphene quantum dots (4N-GQDs), utilizing Density Functional Theory (DFT). We considered six common metal species, namely Ca, Ca, Cr, Cr, Fe, and Fe. Our findings reveal that the curvature of metal and divalent metal ion-doped-4N-GQDs increases as the external electric field strength rises in both positive and negative directions.
View Article and Find Full Text PDFSpectrochim Acta A Mol Biomol Spectrosc
August 2025
Kunming Key Laboratory of Energy Materials Chemistry, Yunnan Minzu University, Kunming 650500, Yunnan, China. Electronic address:
Heavy metals (Fe) and pesticides (diquat) pose serious threats to the environment and human health, necessitating the development of efficient detection technologies. In this study, metal/non-metal doped graphene quantum dots (GQDs) were developed. Given excellent sensitivity, stability and selectivity, it was used as a fluorescent probe with multiple functions for simultaneous detection of two pollutants.
View Article and Find Full Text PDFJ Mater Chem B
August 2025
Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand.
Although recent breakthroughs have brought hope for a complete cure for cancer, early and rapid diagnosis remains crucial for effective treatment. Carbohydrate antigen 19-9 (CA19-9) is a clinically established biomarker widely used in the diagnosis and management of gastric and pancreatic cancers. Accurate detection of CA19-9 is crucial for early diagnosis, treatment monitoring, and predicting recurrence.
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