Nanotechnology - LED

1. Presented By –
Mr. Chetan D. Gandate
M.Sc-II (Physics)
Guided By –
Dr. S. J. Dhoble
Mr. Yatish R. Parauha
DEPT. OF PHYSICS

2.  Introduction
 Importance to study of Energy Saving Lighting Devices
 Synthesis Methods
 Recently Reported Color Tunable Phosphors
 Scope of Lighting Devices
 Future Challenges to Lighting Devices
 Concluding Remark
 References

3.  In a last few years, the consumption of energy of light sources
concerning with biasing of light source became one of the major
problem for the entire world.
 The main demand of the world economy and the global
environment is to saving energy and also reduction in the carbon
emission.
 The main lighting sources are incandescent and fluorescent lights.
Due to the very low luminous efficacy, they are not enough source for
energy saving purposes.
 The fluorescent light is more efficient but they are fragile and
bulky in form.
 The compact fluorescent lamps (CLF) replaces the incandescent
lamps or bulb. But CFL required high starting input current.

4.  Noble prize in physics (2014) honours the researchers (I. Akasaki, H.
Amano, S. Nakamura) of high efficient blue LEDs.
 This offers not only energy saving lighting source but also accrete the
interest of researchers toward LEDs lighting and also leads to the white
light sources.
Invention Of LEDs : Noble Prize 2014

5.  Due to the unique characteristics of LEDs, they are very beneficial in a
many applications. Their characteristics are –
 Compact size and long-life
 Good performance in cold temperature
 Lack of unwanted emission
 Ease of maintenances
 It is very interesting to note that the replacement of 110 million peoples
one 60W bulb by 15W of CFL save energy equivalent to removing 1.3
million cars of the road then option of 9WLED lamp save more twice.
 In such a way, the enhancement of the LEDs in recent years which are
superior over the incandescent and florescent lamps contributes a lion’s
share in the various fields especially for the energy saving purposes.

6.  The low energy requirements of LEDs is the key factor for making
them suitable for renewable lighting solutions.
 It’s always observed that, a large portion of your electricity bills goes
directly toward the paying for the lighting that has been consumed by
you.
 Data provided by the Department of Energy Saving, US; it has been
concluded that around 6% of the household energy has been consumed
by the lighting sources.
 You need to be very careful about your energy consumption because
one careless move by you can destroy lots of energy.

7.  Several physical, chemical methods have been developed to upgrade
the performance of nanomaterials displaying improved properties.
The aim for the various synthesis method is to have a better control over
the particle size and structure.
 Luminescent and non-luminescent nano materials are used today in a
various lighting applications.
 The main and conventional synthesis methods are -
 Solid-State Reaction Method
 Sol Gel Method
 Combustion Method
 Chemical Vapor Deposition (CVD)
Synthesis methods

8. Solid-State Reaction Method
 Solid state reaction method (SSR) is generally most popular and
effective method for synthesis of materials.
 In this method solid precursors are used as a starting materials. This
method is suitable for mass production of materials such as oxides,
(oxy) fluorides, (oxy) chlorides and (oxy) nitrides.
 The main advantage of SSR method is product quality like
homogeneity of phase,high crystallinity, grain size of phosphors, and
luminescence properties.
 In the last decades numerous papers are reported by SSR method.
The main disadvantage of this method is expensive machineries for
high heat treatment.

9. Sol Gel Method
 The sol-gel method is an adaptable process used for the synthesizing
various oxide materials.
 This synthetic method generally allows control of the texture and the
morphological properties of the solid.
 This method has main advantage over the other methods, such as
allowing precipitation, which can be used to introduce dopants.
 The major advantages of the sol-gel technique includes molecular
scale mixing, high purity of the precursors.
 Also significant as homogeneity of the sol-gel products with a high
purity of physical, morphological and chemical properties.

10.  Combustion synthesis process is also known as self-propagating
high-temperature synthesis (SHS). This method is use for the
production of both organic and inorganic by exothermic
combustion reactions in solids of different nature.
 Reactions can occur between a solid reactant coupled with either a
gas, liquid, or other solid.
 If the reactants, intermediates, and products are all solids then it’s
known as a solid flame. If the reaction occurs between a solid reactant
and a gas phase reactant then it’s called infiltration combustion.
 The method of combustion synthesis is a green synthesis technique
that is highly energy efficient, using little if any toxic solvents
Combustion Method

11.  This method of synthesis is often used in the semiconductor
industry for the production of high-purity, high-performance thin
films.
 In a typical chemical vapor deposition (CVD) process, the substrate
is exposed to volatile precursors, which react and decompose on the
substrate surface to produce the desired film.
 The various factors affecting on the quality of the deposited
materials are temperature, the reaction rate, and the concentration of
the precursors.
 The important advantages of this method include the uniform
coating of the nanoparticles or nano film.
Chemical Vapor Deposition (CVD)

12.  Yatish R. Parauha, R.S. Yadav, S.J. Dhoble reported Eu3+ doped
La2(MoO4)3 down conversion phosphors by solid-state reaction method.
 In this research paper, the authors have tried to increase the
photoluminescence intensity through doping of phosphate, sulfate, and
vanadate ions.
 In this work authors are observed 467nm excitation wavelength in the
Eu3+ doped La2(MoO4)3 phosphor.
 This synthesized phosphors also represents intense red color at 614 nm
monitored under 467nm excitation wavelength, which is attributed due to
the 5D0 → 7F2 transition of Eu3+ ion.
 It was also seen that maximum intensity observed at 1 mol %
concentration of Eu3+ ions.

13. It is clear from the figure, the enhancement in PL intensity at 535nm
emission wavelength has minimum and at 614nm emission wavelength
has maximum.
Reportedly, it was observed that the increase in PL intensity is near
about two times to its original intensity.
Fig. A comparison of photoluminescence intensities

14.  A R. Kadam studied energy transfer mechanism in Ce3+, Eu2+
doped/co-doped BaSiF6 phosphor, which is synthesized by solution
combustion method.
 In this work, temperature during synthesis is low at 500 ± 20ᵒC and
urea is used as a fuel material.
 In the investigation, crystal structure, phase purity, morphological,
structural and luminescence properties were studied.
 Under 300nm excitation, Ce3+ activated BaSiF6 phosphor gives broad
emission band in the UV region peaking at 325 nm, 344 nm and 377
nm, which can be attributed to the 4f-5d transition of Ce3+ ions.

15. Fig. (A) PL emission spectra of BaSiF6:0.7mol%Ce3+, xmol%Eu2+
phosphor under 362nm excitation (B) Energy level Ce3+ and Eu2+
 The intensity of the blue emission is increased by about 5.8-fold
compared to the individual Eu2 + blue emission which confirms the
energy transferred from Ce3+ to Eu2+
 Further, PL emission spectra realized blue-red tunable color emission
monitored under 321nm UV excitation.

16.  The innovation of smart lighting technology gives a particular scope
with respect to the energy effectiveness, accommodation and security.
 Lighting is the conscious use of light to accomplish some stylish or
handy impact). It incorporates task lighting, complement lighting, and
general lighting etc.
 The lighting control system serves to give the perfect measure of light
where it is required and expanded luminescence to better accomplish a
particular action.
 The main advantages of a lighting control system over the
independent lighting controls are the ability to control individual.
 The major satisfaction of lighting control system is decrease in the
energy utilization.

17. Future Challenges to Lighting Devices
 The various research reports have been shown that lighting have a
significant impact on concentration, creativity, collaboration, and
ultimately productivity, which has accelerated its adoption in commercial
real estate.
 Human-centric lighting has been around for five years or more but its
definition is still unclear.
 Before introducing new lighting systems, businesses should focus on
increasing the level of natural light in the work environment using
windows or an improved office format.
 At a time when natural light is unimaginable, LEDs provide ideal
qualities compared to the other options and Effectiveness, cost-effective
and ecological benefits of LEDs are evident.

18.  The efficiency of light energy is one of the waves of the future. To
provide the illumination so people can see and also safely navigate the
room.
 With the lighting applications, we are able to creating an atmosphere
and mood as well.
 The lighting application is a not only large but also the rapidly
growing source of energy demand and greenhouse gas emissions.
 LEDs are seen as a future light source for developing as well as
developed countries.
 The low energy requirements of LEDs is the key factor to making
them suitable for endurable lighting solutions for most developing
countries which are still out of reach of electrical networks.

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of phosphate, sulphate and vanadate ions in Eu3+ doped La2(MoO4)3 downconversion
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