Effect of TiO₂ on Altering Direction of Interfacial Charge Transfer in a TiO₂‐Ag‐MPY‐FePc System by SERS

Abstract

Interfacial charge transfer (CT) is of interest owing to its effect on the performance of molecular photovoltaic (PV) devices.T he characteristics and structures of interfacial materials,s uch as TiO 2 nanoparticles (NPs) in some solar cells,are employed to adjust the CT process.Inthis study,three kinds of interfacial systems,i ncluding as olar cell-like TiO 2 -Ag-p-mercaptopyridine (MPY)-iron phthalocyanine (FePc) system, are compared to investigate the interfacial CT process using surface-enhanced Raman scattering (SERS) spectroscopy.The SERS results show the significance of TiO 2 NPs in the system on altering the direction and path of the interfacial CT, which is closely associated with the CT enhancement contribution to SERS in such an interfacial system. SERS spectroscopyi se xpected to be ap romising technique for the exploration and estimation of the interfacial CT behavior in PV devices,which may further extend the applications of SERS in the field of solar cells.

Surface Enhanced Raman Scattering Revealed by Interfacial Charge-Transfer Transitions

“… 103 (Copyright 2018, Royal Society of Chemistry) (B), Wang et al. 104 (Copyright 2019, John Wiley & Sons, Inc.) (C), and Zhou et al. 107 (Copyright 2020, Nature Publishing Group) (D).…”

“…Similarly, an altered direction of the interfacial CT in a TiO 2 -Ag-Mpy-FePc system was also demonstrated in detail by Wang and coworkers, as revealed by SERS ( Figure 7 C). 104 Upon the stepwise introduction of FePc (iron phthalocyanine) and TiO 2 components to an initial Mpy-modified Ag substrate, PICT from Ag nanoparticles to Mpy was inhibited by FePc while being further promoted by TiO 2 , as evidenced by the selective enhancements in the a 1 and b 2 modes, respectively. The inhibition by FePc was ascribed to the FePc-Mpy coordination, leading to an increased energy gap between the Fermi level of the Ag nanoparticles and LUMO level of Mpy.…”

“…For instance, with the demonstration of a solar cell-like TiO 2 -Ag-Mpy-FePc system, the photoelectric performance of the interfacial material was evaluated by SERS in a photovoltaic device. 104 Similarly, the chemical binding types and CT processes, which are critical in dye-sensitized solar cells, were determined by the construction of metal-dye-semiconductor sandwich structures, such as Ag/N719/TiO 2 and Au@Ag/N3/n-TiO 2 systems. 128 , 129 These strategies broaden the scope of SERS applications and make the in situ tracking of the interfacial CT transitions realizable.…”

Charge Transfer in 4-Mercaptobenzoic Acid-Stabilized Au Nanorod@Cu2O Nanostructures: Implications for Photocatalysis and Photoelectric Devices

“…In our previous work, we designed a new strategy based on placing a probe molecule in the pathway of the electrons as they move between the metal and semiconductor, and we found that the SERS spectra of probe molecules changed when CT occurred. The changes in these spectra allowed the indirect deduction of the specific process occurring in the system. − This type of method uses a nonobjective idea to concretely establish the CT process in a metal–semiconductor or even in a semiconductor–semiconductor system.…”

Thickness-Dependent NIR LSPR of Curved Ag/TiS2 Bilayer Film

“…The UV–Vis–NIR spectra for the single Ag films are shown in Figure S4 . The peak at 320 nm was the intrinsic peak of Ag, and peaks around 400–2400 nm corresponded to the plasmon resonance [ 31 ]. As Ag thickness increased, the plasmon resonance peaks of Ag around 400–2400 nm showed a blue-shift and became narrow due to the dielectric constant effect of surrounding medium.…”