1 research outputs found
Enhanced Lifetime of Cyanine Salts in Dilute Matrix Luminescent Solar Concentrators via Counterion Tuning
Organic
luminophores offer great potential for energy harvesting
and light emission due to tunable spectral properties, strong luminescence,
high solubility, and excellent wavelength selectivity. To realize
their full potential, the lifetimes of luminophores must extend to
many years under illumination. Many organic luminophores, however,
have a tendency to degrade and undergo rapid photobleaching, leading
to the perception of intrinsic instability of organic molecules. In
this work, we demonstrate that by exchanging the counterion of a heptamethine
cyanine salt the photostability and corresponding lifetime of dilute
cyanine salts can be enhanced by orders of magnitude from 10 h to
an extrapolated lifetime of greater than 65,000 h under illumination.
To help correlate and comprehend the underlying mechanism behind this
phenomenon, the water contact angle and binding energy of each pairing
were measured and calculated. We find that increased water contact
angle, and therefore increasing hydrophobicity, generally correlates
to improved lifetimes. Similarly, a lower absolute binding energy
between cation and anion correlates to increased lifetimes. Utilizing
the binding energy formalism, we predict the stability of a new anion
and experimentally verify it with good consistency. Moving forward,
these factors could be used to rapidly screen and identify highly
photostable organic luminophore salt systems for a range of energy
harvesting and light-emitting applications