The Raelian Movement
for those who are not afraid of the future : http://www.rael.org
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Artificial White Light Becomes Eye-Friendly
http://www.sciencedaily.com/releases/2010/10/101006085456.htm
ScienceDaily (Oct. 11, 2010) — A new class of organic substances --
discovered by scientists from the Institute of Physical Chemistry of
the Polish Academy of Sciences and the Faculty of Chemistry of the
University of Warsaw -- emits white light with continuous spectrum.
This achievement provides experimental evidence that only a single
component luminophore will be necessary to construct eye-friendly
light sources and displays.
Tired eyes and the impression that white is artificial are known to
everyone who spends time in places lighted by popular non-thermal
sources like fluorescent lamps or LEDs. Scientists from laboratories
all over the world have been trying to eliminate these unpleasant side
effects for years in their search for methods to recreate sunlight,
which is the most natural light for humans. In the Institute of
Physical Chemistry of the Polish Academy of Sciences (IPC PAS), it was
shown that this objective could be achieved. "We have discovered a
class of organic molecules emitting white light with continuous
spectrum covering almost the entire visible range," says Dr Jerzy
Karpiuk from the IPC PAS who heads the research team. It is also
important that the emission of the white light was obtained from one
chemical compound with a very simple structure.
White is a special colour which is created as a result of mixing light
of all wavelengths in the visual range -- i.e., from approximately 420
to 730 nanometres (one nanometer is one billionth part of a meter).
The white colour of fluorescent lamps and similar artificial sources
is created by the mixture of three colours only: red, green and blue,
which come mainly from the non-continuous emissions of various
inorganic (halophosphate or triphosphate) luminophores. The light
obtained in this way is devoid of many colour components, and it is
this effect that is responsible for the unpleasant visual sensations.
In addition, the need to use several substances lowers the energetic
efficiency of light sources and complicates their manufacturing
technology.
The research team composed of Jerzy Karpiuk (IPC PAS), Ewelina Karolak
(IPC PAS) and Jacek Nowacki (Faculty of Chemistry of the University of
Warsaw) observed white light emission continuously covering virtually
the entire visible range. Its source is crystal violet lactone (CVL),
a substance produced in mass quantities and commonly used in copy
paper as the so-called dye precursor. A CVL molecule has two
fluorophores embedded in its structure and responsible for the
emission of light: one for blue and the other one for orange. The
contribution of each of them to CVL's dual fluorescence heavily
depends on the environment of the molecule which modifies the
energetics of their excited states. "By properly adjusting the
molecule's surrounding, it is possible to control the parameters of
the emission spectrum, and consequently, to change the colour or shade
of the white light obtained," says Ewelina Karolak, a PhD student from
the IPC PAS.
"The deeper significance of our research lies in the discovery that
white fluorescence is a general property of CVL type molecules. The
dependence of excited state energetics on molecular structure allows
to predict the width, shape and other parameters of the dual
fluorescence spectrum, and so enables the engineering and customised
design of white fluorophores," adds Dr Karpiuk. It turns out that even
very small molecules can emit continuous white light. This fact opens
up a new perspective for the construction of innovative eye-friendly
light sources.
The emission of white light by molecular structures as simple as CVL
is highly desired and wanted phenomenon, mainly because of its
potential use in organic light-emitting diodes. However, it is still a
long way before it can be used in practice because crystal violate
lactone emits light of low intensity and CVL-based light sources would
not be efficient enough to be manufactured on a mass scale. "However,
the most important thing is that we managed to show that a certain
concept works in practice. Now we are sure that it is only a matter of
time before light sources recreating natural white light will be
constructed," Dr Karpiuk sums up the discovery.
An article on the discovery of white fluorescence was published in
Physical Chemistry Chemical Physics journal.
Story Source:
The above story is reprinted (with editorial adaptations by
ScienceDaily staff) from materials provided by Institute of Physical
Chemistry of the Polish Academy of Sciences, via AlphaGalileo.
Journal Reference:
1. Jerzy Karpiuk, Ewelina Karolak, Jacek Nowacki. Tuneable white
fluorescence from intramolecular exciplexes. Physical Chemistry
Chemical Physics, 2010; 12 (31): 8804 DOI: 10.1039/B927232A
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"Ethics" is simply a last-gasp attempt by deist conservatives and
orthodox dogmatics to keep humanity in ignorance and obscurantism,
through the well tried fermentation of fear, the fear of science and
new technologies.
There is nothing glorious about what our ancestors call history,
it is simply a succession of mistakes, intolerances and violations.
On the contrary, let us embrace Science and the new technologies
unfettered, for it is these which will liberate mankind from the
myth of god, and free us from our age old fears, from disease,
death and the sweat of labour.
Rael
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