Controlled molecular deposition of natural organic molecules such as nucleobases (NBs) into well-defined thin films represents a progress towards exciting new nanomaterials. The strongly emerging atomic/molecular layer deposition (ALD/MLD) technique provides us with an elegant way to realize the depositions through gas phase with atomic/molecular level accuracy. In the resultant thin films the organic molecules are bound together not only with hydrogen bonds but also via metal cation linkers, and are likely to exhibit novel properties. Here we demonstrate the ALD/MLD of such thin films with monovalent sodium, divalent barium or trivalent lanthanum as the metal linker and uracil or adenine as the NB component. Our metal-NB thin films are homogeneous, smooth and in the case of sodium and barium also crystalline showing intense photoluminescence. We discuss the impact of the size and charge of the metal cation on the growth and properties of the films.

We report blue, green, and red upconversion emissions with strongly angular-dependent intensities for a new type of hybrid (Y,Yb,Er)–pyrazine thin films realized using the atomic/molecular layer deposition thin-film fabrication technology. The luminescence emissions in our amorphous (Y,Yb,Er)–pyrazine thin films of a controllable nanothickness originate from three- and two-photon NIR-to-vis excitation processes. In addition to shielding the lanthanide ions from nonradiative de-excitation, the network of interconnected organic molecules serves as an excellent matrix for the Yb3+-to-Er3+ excitation energy transfer. This suggests a new approach to achieve efficient upconverting molecular materials with the potential to be used for next-generation medical diagnostics, waveguides, and surface-sensitive detectors.

Inorganic-organic europium-based hybrid materials have good luminescent properties and play a key role in many important optical applications, such as nanosized phoshoresent and optoelectronic devices. Here we demonstrate the feasibility and potential benefits of synthesizing such materials with a direct deposition method with atomic/molecular level precision using the emerging atomic layer deposition/molecular layer deposition (ALD/MLD) technique. Such a process allows for fundamentally new types of highly uniform and conformal hybrid inorganic-organic thin films by alternating exposures of inorganic and organic reactants on flexible/sensitive/nanostructured surfaces. We employ Eu(thd) 3 a n d 3 , 5 -pyridinedicarboxylic acid as precursors and deposit the films on a variety of substrate materials in the temperature range from 240 to 400 o C. The appreciably fast self-limiting surface reactions yield thin films with high luminescence intensities.We foresee that our Eu-hybrid thin-film phosphors grown by ALD/MLD could be exciting new phosphor materials in applications where ultrathin luminescent coatings on flexible and/or nanostructured surfaces are needed.

Here we show that uracil and sodium form a three-dimensional metal-mediated nucleic acid network; it is grown in atomic/molecular layer-by-layer manner using the atomic/molecular layer deposition (ALD/MLD) thin-film technique. The long-range ordered Na-uracil crystalline structure is evidenced as sharp Bragg reflections. Based on density functional theory (DFT) calculations, a tetrameric-like crystal structure is proposed. Na-uracil thin films are fluorescent with a lifetime three orders of magnitude higher than commonly seen for nucleic acid molecules. Our method provides a new approach to designing 3D nucleic acid-metal nanostructures.

Atomic/molecular layer deposition (ALD/MLD) processes based on Eu(thd)3 and three different aromatic organic acids with O and N donors as precursors are systematically investigated for the growth of Eu-based inorganic–organic thin-film phosphors.