Angular dependent NEXAFS study of the molecular orientation of PTCDA multilayers on Au (111) surface

Atomic-scale investigation of MgO growth on fused quartz using angle-dependent NEXAFS measurements

“… 29 Further, adsorbed organic molecule on Au substrate has revealed angle dependence due to an ordered geometry on the surface. 25 In the same way, adsorbed CO 2 on ZnO also exhibits angular dependence due to the bond geometry, in which one O atom of CO 2 is in the substrate, while second interacts with surface cation. 79 Thus, the factors influencing the angular dependence of fine structures exist too with anisotropic chemical bonds, either in the structure or in the absorbed species.…”

“…Growth procedure for sputtering In order to understand the nature of MgO lm growth systematically, MgO-sputtering target (99.99%) procured from Alfa Aesar was used for sputtering. The MgO target was sputtered on fused quartz substrates using the rf-sputtering method for various deposition durations of 5,10,15,25,36,49,64,81,144,256, and 400 min. 58 The base pressure for sputtering was 5.0 Â 10 À7 torr.…”

“…This leads to a redistribution of the intensity between the spectrum details. Further, evolution of this interaction in different directions could be successfully depicted using angle-dependent NEXAFS spectroscopy for organic molecules, 25 oriented ZnO nanostructures, 26 and Pr 0.67 Sr 0.33 MnO 3 films. 27 Thus, NEXAFS investigations were extended to angle-dependent measurements in the present study.…”

Molecular Orientation and Site Dependent Charge Transfer Dynamics at PTCDA/TiO2(110) Interface Revealed by Resonant Photoemission Spectroscopy

“…It is worth noting that in practical applications photovoltaic devices such as dye-sensitized solar cells (DSSCs) or quantum dot-sensitized solar cells (QDSSCs) made from nanocrystalline TiO 2 film with various highly crystalline morphologies; e.g., nanoparticles, nanotubes, nanowires, nanosheets, etc., are receiving a lot of attention because such structures may improve the device performance. − Specifically, nanocrystalline anatase TiO 2 would be more desirable in DSSCs because of high photoactivity, high surface area for dye adsorption, high light harvesting efficiency, and efficient charge transport properties. − However, the less availability of synthetic techniques for single crystalline anatase TiO 2 strongly influences its application as substrate for model studies. In this regard, the rutile TiO 2 (110) with advantages including chemical stability, commercial availability, well-defined electronic structure, and easy surface cleaning serves as a model surface for fundamental research. − On the other hand, 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) has been widely used in organic electronics and also serves as a model planar organic semiconductor molecule for fundamental research. − It has been studied on a wide range of substrates focusing on morphologies, optical properties, and electronic properties. − In a recent study, we have systematically investigated the electronic structure, chemical interactions, molecular orientations, and energy level alignment at the PTCDA/rutile TiO 2 (110) interface using synchrotron-based photoemission spectroscopy (PES) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. It was found that PTCDA molecules adopt distinct molecular orientations within the first monolayer (ML) region: slightly tilted at 0.5 ML and disordered at 1 ML due to strong interfacial interactions between PTCDA molecules and TiO 2 (110) surface .…”

Analysis of Resonant Soft X-ray Reflectivity of Anisotropic Layered Materials

“…The second feature at about 535 eV was also ascribed to 1s → π* transitions from the bridging O atoms. Features above 538 eV, mainly pronounced in s-scattering, were related to 1s → σ* transitions [35,36].…”