@article{Loague2023,

title = {Impact of Molecular Orientation on Lateral and Interfacial Electron Transfer at Oxide Interfaces},

author = {Quentin Loague and Niklas D. Keller and Andressa V. Müller and Bruno Martín Aramburu-Trošelj and Rachel E. Bangle and Jenny Schneider and Renato N. Sampaio and André Sarto Polo and Gerald J. Meyer},

url = {https://pubs.acs.org/doi/abs/10.1021/acsami.3c05483},

doi = {10.1021/acsami.3c05483},

issn = {1944-8252},

year  = {2023},

date = {2023-07-19},

urldate = {2023-07-19},

journal = {ACS Appl. Mater. Interfaces},

volume = {15},

number = {28},

pages = {34249--34262},

publisher = {American Chemical Society (ACS)},

abstract = {Molecular dyes, called sensitizers, with a cis-[Ru(LL)(dcb)(NCS)2] structure, where dcb is 4,4′-(CO2H)2-2,2′-bipyridine and LL is dcb or a different diimine ligand, are among the most optimal for application in dye-sensitized solar cells (DSSCs). Herein, a series of five sensitizers, three bearing two dcb ligands and two bearing one dcb ligand, were anchored to mesoporous thin films of conducting tin-doped indium oxide (ITO) or semiconducting TiO2 nanocrystallites. The number of dcb ligands impacts the surface orientation of the sensitizer; density functional theory (DFT) calculations revealed an ∼1.6 Å smaller distance between the oxide surface and the Ru metal center for sensitizers with two dcb ligands. Interfacial electron transfer kinetics from the oxide material to the oxidized sensitizer were measured as a function of the thermodynamic driving force. Analysis of the kinetic data with Marcus–Gerischer theory indicated that the electron coupling matrix element, Hab, was sensitive to distance and ranged from Hab = 0.23 to 0.70 cm–1, indicative of nonadiabatic electron transfer. The reorganization energies, λ, were also sensitive to the sensitizer location within the electric double layer and were smaller, with one exception, for sensitizers bearing two dcb ligands λ = 0.40–0.55 eV relative to those with one λ = 0.63–0.66 eV, in agreement with dielectric continuum theory. Electron transfer from the oxide to the photoexcited sensitizer was observed when the diimine ligand was more easily reduced than the dcb ligand. Lateral self-exchange “hole hopping” electron transfer between surface-anchored sensitizers was found to be absent for sensitizers with two dcb ligands, while those with only one were found to hop with rates similar to those previously reported in the literature, khh = 47–89 μs–1. Collectively, the kinetic data and analysis reveal that interfacial kinetics are highly sensitive to the surface orientation and sensitizers bearing two dcb ligands are most optimal for practical applications of DSSCs.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Müller2021,

title = {Interfacial Electron Transfer in Dye-Sensitized TiO2 Devices for Solar Energy Conversion},

author = {Andressa Müller and Wendel Wierzba and Mariana Pastorelli and André Sarto Polo},

url = {https://www.scielo.br/j/jbchs/a/7LPqbMpwLvtXbmbjhQGqpzn/},

doi = {10.21577/0103-5053.20210083},

issn = {0103-5053},

year  = {2021},

date = {2021-09-01},

urldate = {2021-09-01},

journal = {J. Braz. Chem. Soc.},

publisher = {Sociedade Brasileira de Quimica (SBQ)},

abstract = {The development of cost-effective molecular devices that efficiently capture and convert sunlight into other useful forms of energy is a promising approach to meet the world’s increasing energy demands. These devices are designed through a successful combination of materials and molecules that work synergistically to promote light-driven chemical reactions. Light absorption by a surface-bound chromophore triggers a sequence of interfacial electron transfer processes. The efficiencies of the devices are governed by the dynamic balance between the electron transfer reactions that promote energy conversion and undesirable side reactions. Therefore, it is necessary to understand and control these processes to optimize the design of the components of the devices and to achieve higher energy conversion efficiencies. In this context, this review discusses general aspects of interfacial electron transfer reactions in dye-sensitized TiO2 molecular devices for solar energy conversion. A theoretical background on the Marcus-Gerischer theory for interfacial electron transfer and theoretical models for electron transport within TiO2 films are provided. An overview of dye-sensitized solar cells (DSSCs) and dye-sensitized photoelectrosynthesis cells (DSPECs) is presented, and the electron transfer and transport processes that occur in both classes of devices are emphasized and detailed. Finally, the main spectroscopic, electrochemical and photoelectrochemical experimental techniques that are employed to elucidate the kinetics of the electron transfer reactions discussed in this review are presented.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Veiga2021,

title = {Compact TiO2 blocking-layer prepared by LbL for perovskite solar cells},

author = {Elaine Teixeira Veiga and Silvia Letícia Fernandes and Carlos Frederico de Oliveira Graeff and André Sarto Polo},

url = {https://www.sciencedirect.com/science/article/abs/pii/S0038092X20311798},

doi = {10.1016/j.solener.2020.11.024},

issn = {0038-092X},

year  = {2021},

date = {2021-01-15},

urldate = {2021-01-00},

journal = {Solar Energy},

volume = {214},

pages = {510--516},

publisher = {Elsevier BV},

abstract = {Blocking-layer are very important for the overall efficiency improvement in perovskite solar cells, PSCs. This layer must be thin enough to allow the light to reach the perovskite layer and have low electrical resistance for electron flow to the external circuit and, at the same time, inhibit recombination processes on the FTO surface. In this work, the preparation of the TiO2 compact layer by the Layer-by-Layer technique for the use in PSCs is presented. Evaluation of layers having different thickness by several techniques demonstrated that these layers have an optimum thickness and a balance between their electrical resistance and electron recombination is responsible for the improvement in the performance of the cells.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Mamud2021,

title = {Z to E light-activated isomerization of α-pyridyl-N-arylnitrone ligands sensitized by rhenium(I) polypyridyl complexes},

author = {Julia F. Mamud and Giovanna Biazolla and Caroline S. Marques and Giselle Cerchiaro and Thiago B. de Queiroz and Artur F. Keppler and André Sarto Polo},

url = {https://www.sciencedirect.com/science/article/abs/pii/S0020169320312093},

doi = {10.1016/j.ica.2020.120009},

issn = {0020-1693},

year  = {2021},

date = {2021-01-00},

urldate = {2021-01-00},

journal = {Inorganica Chimica Acta},

volume = {514},

publisher = {Elsevier BV},

abstract = {A series of rhenium(I) polypyridyl compounds, bearing photoisomerizable nitrones as ligands, was synthesized and characterized by several techniques. The photochemical and photophysical behaviors of the compounds were investigated. Upon irradiation, acetonitrile solutions of the nitrones, or their respective complexes, exhibit changes in absorption, emission, and FTIR spectra. FTIR revealed the formation of the respective anilide as the photoproducts of irradiation of the uncoordinated nitrones, while irradiation of the complexes resulted in Z → E due to the photosensitized isomerization of the coordinated ligand, also confirmed by HPLC-MS and 1H NMR. The photoisomerization quantum yields are dependent on the nature of the nitrone substituent, which changes the energy of the 3ILZ-NitX excited state, which is populated by photosensitization. 3MLCT becomes the lowest-lying excited state in the E-product and results in an increase in emission intensity. The changes in spectroscopic properties of the Z or E coordinated nitrones can be exploited for molecular devices such as photosensors.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}