Nanoco Technologies Ltd. v. Samsung Electronics Co., Ltd. et al

Filing 1

COMPLAINT against Samsung Advanced Institute of Technology, Samsung Display Co., Ltd., Samsung Electronics America, Inc., Samsung Electronics Co., Ltd., Samsung Electronics Co., Ltd. Visual Display Division ( Filing fee $ 400 receipt number 0540-7664317.), filed by Nanoco Technologies Ltd.. (Attachments: # 1 Civil Cover Sheet, # 2 Exhibit 1, # 3 Exhibit 2, # 4 Exhibit 3, # 5 Exhibit 4, # 6 Exhibit 5, # 7 Exhibit 6, # 8 Exhibit 7, # 9 Exhibit 8, # 10 Exhibit 9, # 11 Exhibit 10, # 12 Exhibit 11, # 13 Exhibit 12, # 14 Exhibit 13, # 15 Exhibit 14)(Henry, Claire)

Exhibit 5

USOO968.0068B2

(12) United States Patent

(10) Patent No.:

VO et al.

US 9,680,068 B2

(45) Date of Patent:

(54) QUANTUM DOT FILMS UTILIZING

Jun. 13, 2017

(2013.01); B32B 2307/7242 (2013.01); B82Y

MULT-PHASE RESNS

20/00 (2013.01); Y10T 156/10 (2015.01)

(71) Applicant: Nanoco Technologies, Ltd., Manchester

(58) Field of Classification Search
CPC ...... H01L 33/502: C09K11/703: C09K11/02
See application file for complete search history.

(72) Inventors: Cong-Duan Vo, Manchester (GB);

(56)

(GB)

References Cited

Imad Naasani, Manchester (GB);

Amilcar Pillay Narrainen, Manchester
(GB)

U.S. PATENT DOCUMENTS
2010, 0123155 A1*

(73) Assignee: Nanaco Technologies Ltd., Manchester

5, 2010 Pickett ................... B82Y 15.00

3f2011 Picket et al.
3/2011 Pickett et al.

2013, OO75692 A1

(*) Notice:

2011/0068321 A1
2011/0068322 A1

(GB)

3/2013 Naasani et al.

Subject to any disclaimer, the term of this

patent is extended or adjusted under 35

U.S.C. 154(b) by 312 days.

FOREIGN PATENT DOCUMENTS
EP

(21) Appl. No.: 14/460,008
(22) Filed:

O

2, 2009

Ramasamy et al. Materials Science in semiconductor Processing 42
O

2016) 334-343.

Prior Publication Data
US 2015/OO47765 A1

2028248 A1

OTHER PUBLICATIONS

Aug. 14, 2014

(65)

257/98

SAG. Male, 2007, 19, 6581.*

Feb. 19, 2015

Parlak et al. ACS Appl. Mater. Interfaces 2011, 3, 4306-4314.*
Supporting information of Parlak 2011.*
Wang et al. Langmuir 2005, 21, 2465-2473.*

Related U.S. Application Data

(60) Provisional application No. 61/865,692, filed on Aug.
14, 2013.

* cited by examiner
Primary Examiner — Mark Kaucher
(74) Attorney, Agent, or Firm — Blank Rome LLP

(51) Int. Cl.
B82. 20/00

(2011.01)

(57)

HOIL 33/50
B32B 37/24
C09K II/70
C09K II/02

(2010.01)
(2006.01)
(2006.01)
(2006.01)

Multi-phase polymer films containing quantum dots (QDS)
are described herein. The films have domains of primarily
hydrophobic polymer and domains of primarily hydrophilic
polymer. QDS, being generally more stable within a hydro

(52) U.S. Cl.
CPC ............ HOIL 33/504 (2013.01); B32B 37/24
(2013.01); C09K II/02 (2013.01); C09K
II/703 (2013.01); HOIL 33/502 (2013.01);
B32B 2037/243 (2013.01); B32B 2307/418

ABSTRACT

phobic matrix, are dispersed primarily within the hydropho
bic domains of the films. The hydrophilic domains tend to be
effective at excluding oxygen.
1 Claim, 4 Drawing Sheets

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U.S. Patent

Jun. 13, 2017

Sheet 1 of 4

US 9,680,068 B2

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U.S. Patent

Jun. 13, 2017

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U.S. Patent

Jun. 13, 2017

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larly, as phosphor films for down-converting light emitted

QUANTUM DOT FILMS UTILIZING

from a solid-state LED semiconductor material.

MULT-PHASE RESNS
FIELD OF THE INVENTION

The invention relates to materials comprising light emit
ting semiconductor quantum dots (QDs), and more specifi
cally, multi-phase polymer films incorporating QDS.
BACKGROUND

Light-emitting diodes (LEDs) are becoming more impor
tant to modern day life and it is envisaged that they will
become one of the major applications in many forms of
lighting such as automobile lights, traffic signals, general
lighting, liquid crystal display (LCD) backlighting and dis
play screens. Currently, LED devices are typically made
from inorganic solid-state semiconductor materials. The
material used to make the LED determines the color of light
produced by the LED. Each material emits light with a
particular wavelength spectrum, i.e., light having a particu
lar mix of colors. Common materials include AlGaAS (red),
AlGalnP (orange-yellow-green), and AlGalnN (green-blue).
LEDs that produce white light, which is a mixture of
fundamental colors (e.g., red, green and blue) or that pro
duce light not available using the usual LED semiconductor
materials are needed for many applications. Currently the
most usual method of color mixing to produce a required
color, such as white, is to use a combination of phospho
rescent materials that are placed on top of the Solid-state
LED whereby the light from the LED (the “primary light')
is absorbed by the phosphorescent material and then re
emitted at a different frequency (the “secondary light'). The
phosphorescent material “down converts” a portion of the
primary light.
Current phosphorescent materials used in down convert
ing applications typically absorb UV or blue light and
convert it to light having longer wavelengths, such as red or
green light. A lighting device having a blue primary light
Source. Such as a blue-emitting LED, combined with sec
ondary phosphors that emit red and green light, can be used
to produce white light.
The most common phosphor materials are solid-state
semiconductor materials, such as trivalent rare-earth doped
oxides or halophosphates. White emission can be obtained
by blending a blue light-emitting LED with a green phos

10

15

an emulsion. A film is formed of the emulsion, which can
then be cured to form a solid film.
25

30

35

40

45

phor such as, SrGaSa:Eu" and a red phosphor such as,
SrSisNis:Eu" or a UV light-emitting LED plus a yellow
phosphor such as, Sr.P.O., Eu"; Mu", and a blue-green

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing Summary as well as the following detailed
description will be better understood when read in conjunc
tion with the appended drawings. For the purpose of illus
tration only, there is shown in the drawings certain embodi
ments. It is understood, however, that the inventive concepts
disclosed herein are not limited to the precise arrangements
and instrumentalities shown in the drawings.
FIG. 1 is a schematic illustration of a prior art use of a film
containing QDs to down-convert light emitted by a LED.
FIG. 2 is a schematic illustration of a QD-containing
polymer sandwiched between transparent sheets.
FIG. 3 is a schematic illustration of a two-phase film
having a QD-compatible phase and an oxygen-excluding
phase.
FIG. 4 is a flowchart illustrating the steps of making a
two-phase film.
FIG. 5 is a plot of QD quantum yields in various films.
FIG. 6 illustrates stability studies of two-phase LMA/
epoxy films.
DESCRIPTION

phosphor. White LEDs can also be made by combining a
blue LED with a yellow phosphor.
Several problems are associated with solid-state down
converting phosphors. Color control and color rendering
may be poor (i.e., color rendering index (CRI)<75), resulting
in light that is unpleasant under many circumstances. Also,
it is difficult to adjust the hue of emitted light; because the
characteristic color emitted by any particular phosphor is a
function of the material the phosphor is made of. If a suitable
material does not exist, then certain hues may simply be

50

unavailable. There is thus a need in the art for down

60

There has been substantial interest in exploiting the
properties of compound semiconductor particles with
dimensions on the order of 2-50 nm, often referred to as

quantum dots (QDS) or nanocrystals. These materials are of
commercial interest due to their size-tunable electronic

properties that can be exploited in many commercial appli
55

converting phosphors having greater flexibility and better
color rendering than presently available.

cations.
The most studied of semiconductor materials have been

the chalcogenides II-VI materials namely ZnS, ZnSe, CdS,
CdSe, CdTe; especially CdSe due to its tunability over the
visible region of the spectrum. Reproducible methods for the
large-scale production of these materials have been devel
oped from “bottom up' techniques, whereby particles are
prepared atom-by-atom, i.e., from molecules to clusters to
particles, using 'wet' chemical procedures.
Two fundamental factors, both related to the size of the

SUMMARY
65

Films containing QDs are described herein. The films may
be used as components for LED lighting devices, particu

The films are formed from two or more polymer materi
als, for example, two or more polymer resins. The films at
least partially phase-separate. Such that some domains
within a film are primarily one of the polymer materials and
other domains within the film are primarily the polymer
material. One of the polymer materials is chosen to be highly
compatible with the QDs. Another of the polymer materials
is highly effective at excluding oxygen. As a result, the
multi-domain films include QD-rich domains of QDs dis
persed in the QD-compatible polymer, those domains being
Surrounded by QD-poor domains of the oxygen-excluding
polymer. Thus, the QDs are suspended in a medium with
which they are highly compatible and are protected from
oxygen by the oxygen-excluding domains.
Methods of making such films are also described herein.
According to some embodiments, QDS are suspended in a
Solution of a first polymer resin (i.e., a QD-compatible
resin). The QD suspension is then added to a solution of the
second polymer resin (the oxygen-excluding resin), yielding

individual semiconductor nanoparticles, are responsible for
their unique properties. The first is the large surface-to
volume ratio. As particles become smaller, the ratio of the

US 9,680,068 B2
3
number of Surface atoms to those in the interior increases.

This leads to the Surface properties playing an important role
in the overall properties of the material. The second factor is
a change in the electronic properties of the material when the
material is very small in size. At extremely small sizes
quantum confinement causes the materials band gap to
gradually increase as the size of the particles decrease. This
effect is a consequence of the confinement of an electron in
a box giving rise to discrete energy levels similar to those
observed in atoms and molecule rather than a continuous

band as observed in the corresponding bulk semiconductor
material. Thus, the “electron and hole' produced by the
absorption of electromagnetic radiation are closer together
than they would be in the corresponding macrocrystalline
material. This leads to a narrow bandwidth emission that

depends upon the particle size and composition of the
nanoparticle material. QDs therefore have higher kinetic
energy than the corresponding macrocrystalline material and
consequently the first excitonic transition (band gap)
increases in energy with decreasing particle diameter.
QD nanoparticles of a single semiconductor material tend
to have relatively low quantum efficiencies due to electron
hole recombination occurring at defects and dangling bonds
situated on the nanoparticle Surface, which may lead to

10

15

25

non-radiative electron-hole recombinations. One method to

eliminate Such defects and dangling bonds on the inorganic
Surface of the QD is to grow a second inorganic material,
having a wider band-gap and Small lattice mismatch to that
of the core material, epitaxially on the surface of the core
particle, producing a “core-shell particle. Core-shell par
ticles separate any carriers confined in the core from surface

30

states that would otherwise act as non-radiative recombina

tion centers. One example is QDS having a ZnS shell grown
on the surface of a CdSe core.

Rudimentary QD-based light-emitting devices have been
made by embedding colloidally produced QDs in an opti
cally clear LED encapsulation medium, typically a silicone
or an acrylate, which is then placed on top of a Solid-state
LED. The use of QDs potentially has some significant
advantages over the use of the more conventional phos
phors, such as the ability to tune the emission wavelength,
strong absorption properties, improved color rendering, and
low scattering.
For the commercial application of QDS in next-generation
light-emitting devices, the QDS are preferably incorporated
into the LED encapsulating material while remaining as
fully mono-dispersed as possible and without significant
loss of quantum efficiency. The methods developed to date
are problematic, not least because of the nature of current
LED encapsulants. QDS can agglomerate when formulated
into current LED encapsulants, thereby reducing the optical
performance of the QDs. Moreover, once the QDs are
incorporated into the LED encapsulant, oxygen can migrate
through the encapsulant to the surfaces of the QDs, which
can lead to photo-oxidation and, as a result, a drop in
quantum yield (QY).
One way of addressing the problem of oxygen migration
to the QDs has been to incorporate the QDs into a medium
with low oxygen permeability to form “beads of such a
material containing QDs dispersed within the bead. The
QD-containing beads can then be dispersed within an LED
encapsulant. Examples of such systems are described in U.S.
patent application Ser. No. 12/888,982, filed Sep. 23, 2010
(Pub. No.: 2011/0068322) and Ser. No. 12/622,012, filed
Nov. 19, 2009 (Pub. No.: 2010/0123155), the entire contents
of which are incorporated herein by reference.

35

40

45

50

55

60

65

4
Films containing QDs are described herein. FIG. 1 illus
trates a prior art embodiment 100, wherein a QD-containing
film 101 is disposed on a transparent substrate 102. Such a
film can be useful, for example, to down-convert primary
light 103 from a primary light source 104 by absorbing
primary light 103 and emitting secondary light 105. A
portion 106 of primary light may also be transmitted through
the film and Substrate so that the total light emanating from
the film and substrate is a mixture of the primary and
secondary light.
QD-containing films, such as film 101 in FIG. 1, may be
formed by dispersing QDS in a polymer resin material and
forming films of the material using generally any method of
preparing polymer films known in the art. It has been found
that QDs are generally more compatible with hydrophobic
resins, such as acrylates, compared to more hydrophilic
resins, such as epoxies. Thus, polymer films made of QDS
dispersed in acrylates tend to have higher initial quantum
yields (QYs) than QD films using hydrophilic resins such as
epoxy resins. However, acrylates tend to be permeable to
oxygen, while epoxy resin polymers and similar hydrophilic
polymers tend to be better at excluding oxygen.
One alternative for achieving high QY associated with
QD-containing hydrophobic films, while also maintaining
stability of the QY over time, is to insulate the film from
oxygen by Sandwiching the film between gas barrier sheets,
as illustrated in FIG. 2. FIG. 2 illustrates a panel 200 having
a polymer film 201 contained between gas barrier sheets 202
and 203. The polymer film 201 contains QDs dispersed
throughout. Gas barrier sheets 202 and 203 serve to prevent
oxygen from contacting the dispersed QDS. However, even
in an embodiment as illustrated in FIG. 2, oxygen can
permeate into the film at edges 204, resulting in a deterio
ration of the QY of the film.
One solution to this problem is to seal edges 204 with an
oxygen barrier. However, doing so adds cost to the produc
tion of panel 200. Another option is to use a polymer 201
that is less permeable to oxygen. But as explained above,
QDS are generally less compatible with Such polymer resins,
and therefore the optical properties of devices utilizing such
polymers are less than ideal.
Multi-phase films utilizing at least a first phase (phase 1)
resin that is compatible with the QD material and at least a
second phase (phase 2) resin that is efficient at rejecting O
are described herein. FIG. 3 illustrate a plan view of such a
film 300, wherein QDS 301 are dispersed in a first polymer
phase 302, which is typically a hydrophobic material such as
an acrylate resin. Regions of the first polymer phase are
dispersed throughout a second polymer phase 303, which is
typically an oxygen-impermeable material Such as epoxy.
The multi-phase films described herein overcome many of
the problems described above. The phase 1 resin is compat
ible with the QDs and therefore allows a high initial QY. The
phase 2 resin is impermeable to oxygen, and therefore
protects the QDs from oxidation without the need to seal the
edges of the panel. As used herein, the term “film' includes,
not only 2-dimensional (i.e. flat) sheets, as illustrated in
FIGS. 1-3, but can also include 3-dimensional shapes.
FIG. 4 is a flowchart illustrating steps of a method of
preparing multi-phase films as described herein. The QDs
are dispersed in a solution of the phase 1 resin (or resin
monomer) 401. As described above, the phase 1 resin is
generally a hydrophobic resin, such as acrylate resins.
Examples of Suitable phase 1 resins include, poly(methyl
(meth)acrylate), poly(ethyl(meth)acrylate), poly(n-propyl
(meth)acrylate), poly(butyl(meth)acrylate), poly(n-pentyl
(meth)acrylate),
poly(n-hexyl(meth)acrylate),
poly

US 9,680,068 B2
5
(cyclohexyl(meth)acrylate), poly(2-ethyl hexyl(meth)
acrylate), poly(octyl(meth)acrylate), poly(isooctyl(meth)
acrylate), poly(n-decyl(meth)acrylate), poly(isodecyl(meth)
acrylate), poly(lauryl(meth)acrylate), poly(hexadecyl(meth)
acrylate), poly(octadecyl(meth)acrylate), poly(isobornyl
(meth)acrylate), poly(isobutylene), polystyrene, poly
(divinyl benzene), polyvinyl acetate, polyisoprene,
polycarbonate, polyacrylonitrile, hydrophobic cellulose
based polymers like ethyl cellulose, silicone resins, poly
(dimethyl siloxane), poly(vinyl ethers), polyesters or any
hydrophobic host material Such as wax, paraffin, vegetable
oil, fatty acids and fatty acid esters.
Generally, the phase 1 resin can be any resin that is
compatible with the QDs. The phase 1 resin may or may not
be cross-linked or cross-linkable. The phase 1 resin may be
a curable resin, for example, curable using UV light. In
addition to the QDS and phase 1 resin (or resin monomer),
the solution of 401 may further include one or more of a
photoinitiator, a cross-linking agent, a polymerization cata
lyst, a refractive index modifier (either inorganic one such as
ZnS nanoparticles or organic one Such as high refractive
index monomers or poly(propylene Sulfide)), a filler Such as
fumed silica, a scattering agent Such as barium sulfate, a
Viscosity modifier, a Surfactant or emulsifying agent, or the

6
are incorporated herein by reference. The QDs were added
to a degassed vial, the toluene evaporated, and the resultant
Solid QD re-dispersed in degassed lauryl methacrylate
(LMA, 2.64 mL) containing IRG819/IRG651 (Igracure(R)
5 photoinitiators (9/18 mg). Trimethylolpropane trimethacry
late (TMPTM) crosslinker (0.32 mL) was added. The mix
ture was further stirred for 30 min under nitrogen affording
phase 1 resin. Films of QDs in phase 1 resin were laminated
between 3M gas barrier layers on an area limited by a 19
10 mmx 14 mmx0.051 mm plastic spacer. The film was cured
with a Mercury lamp for 1 min. Stability testing of the QY
of the QDS in phase 1 resin is represented by square data
points in the plot illustrated in FIG. 5.
15
Example 1B

Two-phase resin was prepared by mixing 148 microliters
of the phase 1 resin with 0.5 mL degassed epoxy (Epotek,
20 OG142) and the mixture was mechanically stirred for 3 min
at 100 rpm under nitrogen. 60 Microliters of the two-phase
resin was then laminated between 3M gas barrier layers on
an area limited by a 19 mmx 14 mmx0.051 mm plastic
spacer. The film was cured with a Mercury lamp for 1 min.
like.
25 Stability testing of the QY of the QDs in two-phase resin
The QD-phase 1 resin dispersion can then be mixed with comprising acrylate (phase 1) and epoxy (Epotek OG142,
a solution of the phase 2 resin (or resin monomer) 402. As phase 2) is represented by diamond-shaped data points in the
explained above, the phase 2 resin is a better oxygen barrier plot illustrated in FIG. 5.
than the phase 1 resin. The phase 2 resin is generally a
Example 2
hydrophilic resin. The phase 2 resin may or may not be 30
cross-linkable. The phase 2 resin may be a curable resin, for
example, curable using UV light. Examples of phase 2 resins
Green InP/ZnS QDs (120 Optical Density (OD)) were
include epoxy-based resins, polyurethanes-based resins, prepared as described in U.S. patent application Ser. No.
hydrophilic (meth)acrylate polymers, polyvinyl alcohol,
13/624,632, filed Sep. 23, 2011. The QDs were added to a
poly(ethylene-co-vinyl alcohol), polyvinyl dichloride, sili- 35 degassed vial and dispersed in degassed lauryl methacrylate
cones, polyimides, polyesters, polyvinyls, polyamides,
(LMA, 2.64 mL) containing IRG819/IRG651 photoinitia
enphenolics, cyanoacrylates, gelatin, water glass (sodium tors (9/18 mg). TMPTM crosslinker (0.32 mL) was added.
silicate), PVP (Kollidon). The solution of phase 2 resin may The mixture was further stirred for 30 min under nitrogen
also include one or more of a photoinitiator, a cross-linking affording phase 1 resin. Two-phase resin was prepared by
agent, a polymerization catalyst, a Surfactant or emulsifying 40 mixing 148 microliters of the phase 1 resin with 0.5 mL
degassed polyurethane acrylate (Dymax OP4-4-26032) and
agent, or the like.
According to some embodiments, the phase 1-phase 2 the mixture was mechanically stirred for 3 min at 100 rpm
mixture forms an emulsion 403, typically and emulsion of under nitrogen. 60 Microliters of the two-phase resin was
phase 1 resin Suspended in phase 2 resin. The emulsion then laminated between 3M gas barrier layers on an area
composition can be adjusted by adjusting the relative con- 45 limited by a 19 mmx14 mmx0.051 mm plastic spacer. The
centrations of phase 1 and phase 2 resins, the rate of Stirring film was cured with a Mercury lamp for 1-5 min. Stability
of the mixture, the relative hydrophobicity of the resins, and testing of the QY of the QDs in two-phase resin comprising
the like. One or more emulsifying agents, Surfactants, or acrylate (phase 1) and polyurethane acrylate (Dymax OP-4other compounds useful for Supporting stable emulsions 26032, phase 2) is represented by triangle-shaped data
may be used.
50 points in the plot illustrated in FIG. 5.
According to certain embodiments, such as the embodi
Example 3
ment illustrated in FIG. 2, the resin mixture is laminated
between gas barrier films 404. Examples of gas barrier films
Green InP/ZnS QDs (120 Optical Density (OD)) were
include FTB3-50 (available from 3M, St. Paul, Minn.) and
GX50W or GX25W (available from Toppan Printing Co., 55 prepared as described in U.S. patent application Ser. No.
13/624,632, filed Sep. 23, 2011. The QDs were re-dispersed
LT, Japan). Upon curing 405, the laminated resin film yields
a polymer film having regions of phase 1 polymer, contain in degassed lauryl methacrylate (LMA, 1.2 mL) by Stirring
ing QDS, dispersed throughout phase 2 polymer, as illus under nitrogen overnight. IRG819 photoinitiator (3 mg) was
trated in FIG. 3.
dissolved in 0.6 mL of the QD dispersion in LMA. TMPTM
60 crosslinker (0.073 mL) was then added. The mixture was
EXAMPLES
further stirred for 30 min under nitrogen, affording phase 1
resin with QD concentration at 89.2 OD/mL. Two-phase
Example 1A
resin was obtained by mixing 67 microliters of phase 1 resin
with 0.43 mL degassed epoxy (Epotek, OG142), upon which
Green InP/ZnS QDs (120 Optical Density (OD)) were 65 the mixture was mechanically stirred for 3 min at 100 rpm
prepared as described in U.S. patent application Ser. No. under nitrogen. 60 Microliters of the two-phase resin was
13/624,632, filed Sep. 23, 2011, the entire contents of which then laminated between 3M gas barrier layers on an area

US 9,680,068 B2
8

7
limited by a 19 mm x 14 mmx0.051 mm plastic spacer. The
films were cured with a Mercury lamp for 1 min.
Example 4
Green InP/ZnS QDs (120 Optical Density (OD)) were
prepared as described in U.S. patent application Ser. No.
13/624,632, filed Sep. 23, 2011. The QDs were dispersed in
degassed lauryl methacrylate (LMA, 2.64 mL) containing
IRG819/IRG651 photoinitiators (9/18 mg) by stirring under
nitrogen overnight. TMPTM crosslinker (0.32 mL) was

Effect of Refractive Index of Phase

2 Resin (RI of phase 1 resin = 1.47).
Sam Initial Initial Phase 2
5

1

60

69 Urethane

2-phase 2-phase
QY
EQE

1.47

60

72

1.55

S4

59

1.58

69 Urethane
10
69

acrylate
(Dymax OP4
4-26032)
Epoxy
(Epotek
OG142)

59

58

15

25

30

35

40

45

50

As shown in Table 1, when the RI of the first phase and
that of the second phase are matched, the initial QY and
EQE of the film is maximized. When there is mismatch
between the RIs of the first and second phase resins, the
initial QY and EQE of the film is reduced. Thus, it is
beneficial, where possible, to use first and second phase
resins that have closely matched RIs. According to some
embodiments, the RIs of the two resins differ by less than
about 5%. According to some embodiments, the RIs of the
two resins differ by less than about 1%.
Accordingly, additives such as Surfactants, viscosity
modifiers, monomers, light scattering agents, and other
inorganic Surface tension modifiers may be used to adjust the
RI of one or both phases so that the RIs match. Such
additives may also be used to minimize chemical interaction
between the phases. Moreover, chemical anti-oxidants (di
laurylthiodipropionate, octadecylsulfide, octadecanethiol,
cholesteryl palmitate, Zinvisible, ascorbic acid palmitate,
alpha tocopherol, BHA, BHT, octane thiol, lipoic acid,
gluthathion, sodium metabisulfite, trioctyl phosphine (TOP),
tetradecylphosphonic acids, polyphenols) may be added to
one or both phases to minimize the degradation of QDS
around the edges of the two-phase/gas barrier encapsulated
QD films.
The inventive concepts set forth herein are not limited in
their application to the construction details or component
arrangements set forth in the above description or illustrated
in the drawings. It should be understood that the phraseology
and terminology employed herein are merely for descriptive
purposes and should not be considered limiting. It should
further be understood that any one of the described features
may be used separately or in combination with other fea
tures. Other invented Systems, methods, features, and advan
tages will be or become apparent to one with skill in the art
upon examining the drawings and the detailed description
herein. It is intended that all such additional systems,
methods, features, and advantages be protected by the
accompanying claims.
What is claimed is:

55

and above T70 606 for at least 2000 hours.
Effect of Refractive Index of Phase 2 Resin

The phase 1 LMA resin used in the above Examples has
a refractive index (RI) of 1.47. Table 1 illustrates the effect
of the RI of the phase 2 resin effects the optical properties
of the two-phase films.

RI of cured
Phase 2 Resin

QY EQE Resin
acrylate (OP4
4-20639)

added. The mixture was further stirred for 30 min under

nitrogen affording phase 1 resin. Non-crosslinkable, non
Viscous acrylate phase 2 resin was prepared by dissolving
10.1 mg IRG819 in deoxygenated glycidyl methacrylate
(GMA, 1 mL). Non-crosslinkable, viscous acrylate phase 2
resin was prepared by dissolving polyvinylidene chloride
(PVDC, Saran F310, 1.5 g) in deoxygenated GMA/IRG819/
IRG651 (8.5 mL/57.5 mg/115.3 mg) solution. Two-phase
resin was obtained by mixing 148 microliters of the phase 1
resin with 0.5 mL degassed phase 2 resin and the mixture
was mechanically stirred for 3 min at 100 rpm under
nitrogen. 60 microliters of the two-phase resin was then
either added to the well of a 19 mmx14 mm glass plate or
laminated between 3M gas barrier layers on an area limited
by a 19 mmx14mmx0.051 mm plastic spacer. The film was
finally cured with Mercury lamp for 5 min.
Stability of Resin Films
FIG. 5 is a plot illustrating the quantum yield of resin
films of QDs upon exposure to a blue backlight unit (BLU)
for amounts of time (time, in days, denoted on the X-axis).
The QY of green QDs in a single-phase LMA resin, as
prepared in Example la above, is represented by Square data
points 501. The single-phase resin film has an initial QY of
about 60%, but the QY drops substantially during the first
week of exposure.
Diamond-shaped data points 502 represent the QY of a
two-phase film of LMA/epoxy resin containing QDS pre
pared as describe in Example 1b above. The initial QY of the
LMA/epoxy two-phase film is also about 60%, but unlike
that of the single-phase film, the QY of the two-phase film
remains constant over the time period of the experiment. The
stability of the QY indicates that the two-phase film effec
tively prevents oxidation of the QDs.
Triangle-shaped data points 503 represent QY a two
phase film of QDs in LMA/polyurethane acrylate, as pre
pared in Example 2 above. The initial QY of the LMA/
polyurethane acrylate film is about 45% and remains stable
for over three months. FIG. 6 illustrates stability studies of
the two-phase LMA/epoxy film prepared in Example 1b.
LED intensity 601, efficacy 602, photoluminescence inten
sity 603, QD/LED ratio 604, and % EQE 605 remain stable

ple

60

1. A method of preparing a film, the method comprising:
forming an emulsion comprising a first phase that com
prises a first polymer and quantum dots and a second
phase that comprises a second polymer;
depositing the emulsion between gas barrier sheets to
form a film; and

curing the first and second polymers.
k

k

k

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