Tailoring Ordered Mesoporous Titania Films via Introducing Germanium Nanocrystals for Enhanced Electron Transfer Photoanodes for Photovoltaic Applications

• Based on a diblock-copolymer templated sol–gel synthesis, germanium nanocrystals (GeNCs) are introduced to tailor mesoporous titania (TiO2) films for obtaining more efficient anodes for photovoltaic applications. After thermal annealing in air, the hybrid films with different GeNC content are investigated and compared with films undergoing an argon atmosphere annealing. The surface and inner morphologies of the TiO2/GeOx nanocomposite films are probed via scanning electron microscopy and grazing-incidence small-angle X-ray scattering. The crystal phase, chemical composition, and optical properties of the nanocomposite films are examined with transmission electron microscopy, X-ray photoelectron spectroscopy, and ultraviolet–visible spectroscopy. Special focus is set on the air-annealed nanocomposite films since they hold greater promise for photovoltaics. Specifically, the charge–carrier dynamics of these air-annealed nanocomposite films are studied, and it is found that, compared with pristine TiO2 photoanodes, the GeNC addition enhances the electron transfer, yielding an increase in the short-circuit photocurrent density of exemplary perovskite solar cells and thus, an enhanced device efficiency as well as a significantly reduced hysteresis. 

Subject headings

NATURVETENSKAP  -- Kemi -- Materialkemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Materials Chemistry (hsv//eng)

Keyword

enhanced electron transfer

germanium nanocrystals

ordered mesoporous nanostructures

photoanodes

titania

Annealing

Electron transitions

Electron transport properties

Germanium

Germanium compounds

High resolution transmission electron microscopy

Nanocomposites

Nanocrystals

Optical properties

Perovskite

Perovskite solar cells

Photocurrents

Scanning electron microscopy

Sols

TiO2 nanoparticles

Titanium dioxide

X ray photoelectron spectroscopy

X ray scattering

Chemical compositions

Grazing incidence small-angle X-ray scattering

Mesoporous titania

Ordered mesoporous

Photovoltaic applications

Short-circuit photocurrent densities

Visible spectroscopy

Nanocomposite films

Publication and Content Type

ref (subject category)

art (subject category)