Photocatalytic oxidation of the organic monolayers on TiO₂ surface investigated by in-situ sum frequency generation spectroscopy

Conformational disorder of organic cations tunes the charge carrier mobility in two-dimensional organic-inorganic perovskites

“…It is found that although the ratio has a little variation for different thicknesses, the dependence of the ratio on the alkyl chain length follows similar trend for the films with the same thickness. It is noted that different vibrational modes of organic or polymer films in window geometry have been reported to be affected by many factors including substrate-molecule interaction 60 , phase transition 61 , and film thickness 62 , 63 . However, in our experiments, we employ a near-total-internal-reflection geometry (SiO 2 prisms) to collect SFG spectra at room temperature.…”

Anisotropic Adsorption of 2-Phenylethyl Alcohol on a Rutile (110) Surface

“…The surface-specific SFVS is well-known to be an effective tool for probing molecular adsorptions. It can provide information on their adsorption configurations and bonding properties and work under a wide variety of environment. − From SF spectra detected under various geometries, we found that unlike in the examples mentioned above, 2PA prefers to adsorb on rutile (110) with rings standing up and aligned perpendicularly to O br rows. This configuration is supported by the ab initio calculation, which also reveals that besides the major interaction between the 2PA hydroxyl group (OH 2PA ) and Ti 5c sites, the H-bonding between OH 2PA and nearby O br is responsible for the preferred ring orientation.…”

“…In the lattice coordinate, the resonance amplitude of the υ s mode is expressed by with { i, j, k }∈{ a, b, c } ( a // [001]), { l, m, n }∈{ξ, η, ζ}, and f (Ω) = f (θ, ϕ, ψ) being the orientation distribution function of 2PA molecules on rutile (110). The strong showing of ring vibrational modes indicates that adsorbed 2PA molecules are highly polar ordered . We thus assume a delta distribution of the polar angle θ between ζ and c axes, following the usual approach in SFVS analyses of highly ordered adsorbates. , The deduced polar angle indicates the average polar orientation of corresponding moieties .…”

“…The strong showing of ring vibrational modes indicates that adsorbed 2PA molecules are highly polar ordered. 30 We thus assume a delta distribution of the polar angle θ between ζ and c axes, following the usual approach in SFVS analyses of highly ordered adsorbates. 33,35 The deduced polar angle indicates the average polar orientation of corresponding moieties.…”