Aluminum oxides as alternative building blocks for efficient layer-by-layer blocking layers in dye-sensitized solar cells

Lucas L Nascimento; Jessica G Brussasco; Igor A Garcia; Leonardo F Paula; A S Polo; Antonio Otavio T Patrocinio

doi:10.1088/1361-648X/abc30e

Aluminum oxides as alternative building blocks for efficient layer-by-layer blocking layers in dye-sensitized solar cells

J Phys Condens Matter. 2020 Nov 5;33(5). doi: 10.1088/1361-648X/abc30e.

Authors

Lucas L Nascimento¹, Jessica G Brussasco¹, Igor A Garcia¹, Leonardo F Paula¹, A S Polo², Antonio Otavio T Patrocinio¹

Affiliations

¹ Laboratory of Photochemistry and Materials Science-LAFOT-CM, Instituto de Química, Universidade Federal de Uberlândia, 38400-902 Uberlândia, MG, Brazil.
² Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, 09210-580 Santo André, São Paulo, Brazil.

PMID: 33080580
DOI: 10.1088/1361-648X/abc30e

Abstract

All inorganic layer-by-layer (LbL) thin films composed by TiO₂nanoparticles and [Al(OH)₄]^-anions (TiO₂/AlO_x) as well as Al₂O₃and Nb₂O₅nanoparticles (Al₂O₃/Nb₂O₅) have been deposited to fluorine-doped tin-oxide coated glass (FTO) surfaces and applied as blocking layers in dye-sensitized solar cells (DSCs). Structural and morphological characterization of the LbL films by different techniques reveal that inTiO₂/AlO_xassembly, aluminate anions undergo condensation reactions on the TiO₂surface leading to the formation of highly homogeneous films with unique optical properties. After 25 depositions transmittance losses below 10% in relation to the bare FTO substrate are observed. Electrochemical impedance spectroscopy shows thatTiO₂/AlO_xlayers impose an effective barrier for the charge recombination at FTO/electrolyte interface with an electron exchange time constant 50-fold higher than that for bare FTO. As a result, an improvement of 85% in the overall conversion efficiency of DSCs was observed with the employment of TiO₂/AlO_xblocking layers.Al₂O₃/Nb₂O₅LbL films can also work as blocking layers in DSCs but not as efficient, which is associated with the poor homogeneity of the film and its capacitive behavior. The production of cost-effective blocking layers with a low light scattering in the visible region is an important feature toward the application of DSC in other Building-integrated photovoltaic applications.

Keywords: building-integrated photovoltaics; interfacial charge recombination; metal oxide semiconductors; solar energy conversion; surface engineering.