The work reported outlines the synthesis, film formation and application of NIR-absorbing metal dithiolene and metal diimine molecules suitable for film formation with varying ligands and central metals. Formation of an electroactive film on conducting glass or mesoporous TiO<sub>2</sub> support can be achieved through electropolymerisation, electrodeposition, spin/drop coating or chemical attachment. In this context, we will outline the synthesis, characterisation and properties of a new family of NIR-absorbing aromatic metal diimine complexes. These complexes are shown to give rise to planar, delocalised structures with small HOMO-LUMO gaps, through the use of extended non-innocent ligands <i>o</i>-semibenzoquinonediimines. Herein we report the synthesis of a series of metal diimine complexes, modified to extend the electronic conjugation and shift the intense low-energy absorption from the visible to the NIR region. This study extends the range of available NIR absorping metal-complex chromophores and opens up new possibilities for wavelength tuning and application.
Lanthanide based dyes belong to one of the most promising fields of photovoltaic research,
combining high quantum yields and large spectral shift. However, many challenges are faced when
working with lanthanide dyes for spectral conversion: their thermal and chemical stability, which
can greatly influence the shelf-life of the dyes; the absorption band position, which depends on the
organic part of the dye, the so called "antenna"; self-quenching mechanisms, which lead to a
photoluminescence emission loss. The chemical composition of the surrounding environment of the
dyes has a fundamental role in their properties. In this paper, the optical and PLQY
(photoluminescence quantum yield) properties of an europium-based dye embedded in a silica
matrix are reported. The in-house synthesized dye consists of a bis(2-
(diphenylphosphino)phenyl)ether oxide (DPEPO) ligand and three hexafluoroacetylacetonate (hfac)
co-ligands coordinating a central europium ion. The dye has been included in porous core-shell
particles, to study its optical properties once embedded in a solid dielectric matrix. The optical
properties of the resulting samples have been characterized by photoluminescence emission and
PLQY measurements. The results have been compared with data obtained from a commercially
available dye (BASF Lumogen family) in similar conditions.