Layer-by-layer assembled multilayer TiO(x) for efficient electron acceptor in polymer hybrid solar cells.

Area of Science:

• Materials Science
• Nanotechnology
• Renewable Energy

Background:

• Conventional titanium oxide (TiO(x)) films are crucial in photovoltaic cells.
• The sol-gel process is a common method for fabricating TiO(x) films.
• Improving the efficiency of photovoltaic cells remains a key challenge in renewable energy research.

Purpose of the Study:

• To investigate the impact of electrostatic layer-by-layer (LbL) assembly on TiO(x) nanocomposite film properties.
• To compare the photovoltaic performance of LbL-fabricated TiO(x) nanocomposite films with conventionally fabricated TiO(x) films.
• To elucidate the mechanisms behind efficiency improvements in hybrid solar cells utilizing LbL TiO(x) nanocomposites.

Main Methods:

• Fabrication of TiO(x) nanocomposite (TiO(x)NC) films using electrostatic layer-by-layer (LbL) assembly with titanium precursor/poly(allylamine hydrochloride) (PAH).
• Integration of LbL TiO(x)NC films into planar bilayer TiO(x)NC and poly(3-hexylthiophene) (P3HT) solar cells.
• Characterization of film composition and structure using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and grazing incidence wide-angle X-ray scattering (GIWAXS).

Main Results:

• LbL-assembled TiO(x)NC films significantly improved the power conversion efficiency of P3HT solar cells compared to sol-gel processed films.
• Enhanced efficiency was attributed to a higher Ti(3+)/Ti(4+) ratio and more reactive crystal facets in LbL TiO(x)NC films, improving electron transfer.
• GIWAXS revealed more highly oriented P3HT stacks parallel to the substrate on LbL TiO(x)NC films, potentially enhancing hole mobility and interfacial energy transfer.

Conclusions:

• Electrostatic layer-by-layer assembly is a promising method for fabricating TiO(x) nanocomposite films for high-efficiency photovoltaic applications.
• The LbL approach offers superior control over film chemistry and morphology, leading to enhanced photovoltaic performance.
• This study demonstrates a viable strategy for designing advanced hybrid solar cells with improved power conversion efficiency.