image: Figure | Working principle of the quantum-emitting sites from thiol-induced localized excitons in MoS2. a, DNA origami-programmable thiol-MoS2 hybrid assembly. Top panel: Schematic illustration of a DNA origami triangle positioned on a hydrophilic, hydroxyl group covered binding site (green) on a hydrophobic, methyl group covered surface of Si/SiO2 chip and a thiol–origami-MoS2 assembly. Middle panel: The various steps of the fabrication process of a thiol–origami-MoS2 assembly. Bottom panel: AFM images of DNA origami triangles and optical microscope images of MoS2 flake before and after transferring onto an origami pattern. b, DNA origami-programmable single-photon emission in MoS2–thiol molecule hybrids, involving low-temperature (4 K) PL spectrum, Correlation function, and time-resolved PL. c, Schematic of exciton localization in thiol-functionalized MoS₂, showing the total density of states with donor-type defect states 80 meV below the conduction band that trap excitons for single-photon emission, while the PL intensity ratio of localized to free excitons rises with DNA triangle density.
Credit: Shen Zhao et al.
Solid-state single-photon emitters (SPEs) in atomically thin TMDs provide a scalable and robust platform for quantum memory in quantum networks due to their tunable emission and compatibility with nanoscale integration. Molecular surface functionalization provides an alternative technique, enabling quantum defects and hybrid 2D devices via charge doping or energy-transfer states. However, conventional solution- or lithography-based methods offer limited control over molecule placement and stability, making the development of scalable, deterministic, and precise SPE fabrication a critical challenge.
In a recent paper in Light: Science & Applications, an international team from Nanjing University, Skolkovo Institute of Science and Technology (Skoltech), and LMU Munich reports programmable 2D material–organic molecule hybrids with high efficiency and nanoscale spatial precision. Using dry-stamp transfer, the authors place micron-scale, chemical-vapor-deposited (CVD) MoS2 monolayers onto chips patterned with DNA origami triangles bearing thiol molecules, thereby engineering hybrid platforms that form arrays of solid-state single-photon-emitter (SPE) ensembles with nanosecond lifetimes and excellent spectral and intensity stability. Moreover, by tuning the square-lattice period of the thiol–origami patterns, they achieve unprecedented, geometry-defined control over the density of localized excitons. This approach provides a versatile platform for nanoscale engineering of 2D materials’ electronic properties and opens a route toward miniaturized hybrid inorganic–organic devices with enhanced performance, enabling next-generation on-chip circuits and quantum emitters for quantum communications.
The quantum light emitters are built on the chemisorption of thiols at sulfur vacancies in monolayer MoS2. Binding of a thiol molecule creates a localized trapping potential near the adsorption site—analogous to donor-like defect states—that can efficiently confine excitons and thereby enable bright quantum light emission. This mechanism underpins the remarkably high yield and density of the resulting quantum light sources.
The authors summarize the operating principle of their DNA-origami-programmed functionalization of MoS2 as follows:
“We tune the optical properties of monolayer MoS2 via functionalization with thiol molecules, precisely positioned on chip surfaces using a DNA origami placement technique: (1) the thiolated strands on each individual DNA triangle bind to MoS2, forming trapping sites for excitons with an energy 50 meV lower than that of the free exciton in MoS2; (2) the value of the second-order photon-correlation function g(2)(0), well below the 0.5 threshold, demonstrates single-photon emission from our thiol–origami patterned MoS2; (3) the nanosecond lifetime of the quantum emitters demonstrates minimal photobleaching, blinking, and spectral diffusion.”
Looking ahead, they emphasize scalability:
“These methods offer practical pathways to extend our technique from the current proof of concept and toward wafer-scale fabrication.”
They further highlight the performance and prospects of the platform:
“We achieve an approximately 90% yield in quantum-emitter placement with a mean positioning accuracy of ~13 nm. Our method provides a platform for precisely engineering the electronic properties of 2D materials at the nanoscale and opens a path toward producing miniaturized hybrid inorganic–organic devices with enhanced performance. These results highlight DNA origami as a unique and versatile tool for customizing MoS₂ materials with precisely targeted localized quantum defects acting as single-photon emitters. Further tuning of the number of thiol molecules per origami and exploring different organic molecules provides a route to improve single-photon purity and generate chiral quantum light,” the authors conclude.
Article Title
Deterministic quantum light emitters in DNA origami-engineered molecule-MoS2 hybrids