8La20Research Digest Figure 1. a) FE-SEM images of the surface and cross-section of MC@AAO widened for 3 minutes. b) SEM-EDX mapping images of MC@OAAO at the bottom widened for 3 minutes. c) PL of MC@OAAO widened at different times. The correlation between reflectance and PL peak positions of MC@OAAO d) without and e) with widening for 3 minutes.References(1) K. Kirakci, S.Cordier, C. Perrin, Z. Anorg. Allg. Chem., 63 (2005) 411-416; (2) T. K. N. Nguyen, A. Renaud, M. Wilmet et al., J. Mater. Chem. C, 5 (2017)10477-10484; (3) T. K. N. Nguyen, N. Dumait, F. Grasset et al., ACS Applied Materials & Interfaces, 12 (2020) 40495-40509; (4) A. Renaud, T.K.N. Nguyen, F. Grasset, et al., Electrochimica Acta, 17 (2019) 37-745; (5) K. Harada, T. K. N. Nguyen, F. Grasset, et al., NPG Asia Mater., 14 (2022) 21. (6) J.F. Dechézelles et al. Phys. Chem. Chem. Phys., 12 (2010)11993-11999. (7) L.C. Chen, C.H. Kao, Sci. Rep., 12 (2022) 14750. (8) T. K. N. Nguyen et al. Mater. Today Chem. 27 (2023) 101351.within an inverse opal photonic crystal. The size of the periodical pores, surface modification, and chemical composition of the infiltration material of the inverse opal film have been investigated to control the photonic bandgap in the visible range and the efficiency of the deposited Mo6 cluster. The photoactive Mo6 clusters act as a visible light harvester and generate an efficient photo-induced current upon light absorption that is enhanced by a slow photon effect occurring at the photonic stopband edges. The electron and proton are transferred in the inorganic-organic network via hydrogen bonds by a hopping mechanism to generate a rapid photoconductivity response during light irradiation. Specific attention focused on the role of humidity and temperature regarding the reproducibility of the experiments and the photosensitivity of the nanocomposite. The suitable tunable photo-induced conduction property in organic-inorganic materials opens a new opportunity for the applicability of cluster-based compounds in visible optoelectronic devices [T.K.N. Nguyen, et al., 2023].Photonic crystal for enhanced photocatalytic propertiesThe metal oxide photonic crystals (TiO2, SnO2, In2O3, CuO, etc.) incorporated with metal atom clusters were prepared resulting in different stopbands in the visible range. The purpose was to increase the light absorbance in the visible range for improvement of the photocurrent or photocatalytic properties. The preliminary results indicated that photocatalytic properties were enhanced in the visible range that overlapped with the edge of the stopband of photonic crystal films. Photonic Crystals for Metal Cluster-based Optoelectronic ApplicationsThi Kim Ngan NGUYEN1. Outline of ResearchThe face-capped [M6Li6]n- cluster unit, composed of a central Mo6 cluster, eight face-capping inner ligands (i for inner; Li = halogen or chalcogen), and six apical ligands in the terminal positions (a for apical; La = halogen, OH-, H2O, N3, OCOCnH2n+1, etc.), has been attracted due to its interesting photochemical and redox properties based on the delocalization of the valence electrons on the metal centers [1]. Advanced optical properties have been utilized in the design of optical-related devices, phosphorescent nanocluster emitters, saving-energy devices, photodetectors, photoelectrodes for DSSC, and photocatalytic electrodes for water splitting [2-4]. In addition, the tunable photo-induced electronic property of the MC with other functional materials has been recently investigated which will be a fascinating property for optoelectronic devices [5]. However, the emitting light extraction efficiency was challenged due to the strong scattering effect. Only one study has revealed an enhancement of the photoluminescence (PL) of these clusters (MC) by using the engineering of the 3D silica colloidal photonic crystals but efficiency was not significant [6]. As is known, 1D anodic aluminum oxide (AAO) has been investigated in delocalizing the emitting light resulting in a remarkable improvement of the external quantum efficiency by 1280% for CsPbBr3 perovskite LED [7]. Recently, the enhancement of visible light harvesting or an efficient photoconductivity response has been improved for materials by using photonic crystals [8]. In this study, 1D anodic aluminum oxide and 3D photonic crystal structures were prepared with various porosities and periodic structures for delocalizing the refracting or scattering light for specific applications based on photoactive metal atom clusters. 2. Research ActivitiesPhotonic crystal for enhanced photoluminescenceThe enhanced photoluminescence of the Mo6 cluster was first reported by its incorporation into the anodic aluminum oxide (AAO), a photonic structure to delocalize the emission light. Two AAO structures with different pore sizes, densities, and shapes were controlled by pore widening treatment. The deposition of the negatively charged clusters at the bottom of the ordered AAO resulted in narrowing the PL peak at 680 nm with an enhanced intensity of 230% (Fig. 1). In addition, the disordered AAO supported the deposition of clusters on the surface that efficiently adjusted the shift of the PL peak position, obtaining a high intensity by more than 300% in comparison with that of clusters deposited on the ITO-coated glass. The cluster-integrated photonic crystal could be an interesting material for applications that require efficient luminescence. The article based on this work is under revision in the journal Materials Letter.Photonic crystal for enhanced optoelectronic propertiesSolar energy-harvesting materials have significantly contributed to the development of energy-saving applications for several decades. We have mainly used a new concept composed of the electrophoretic deposition technique and photonic crystal structural engineering to understand the tunable light absorption and electronic conduction properties. A hexamolybdenum cluster compound (denoted as the Mo6 cluster) was successfully functionalized on a tin pyrophosphate semiconductor integrated
元のページ ../index.html#22