U.S. patent application number 13/158045 was filed with the patent office on 2012-10-11 for power-generating module with solar cell and method for fabricating the same.
Invention is credited to Bau-Tong Dai, Jung Y. Huang, Wen-Hsien Huang, Hao-Chung Kuo, Chang-Hong Shen, Jia-Min SHIEH.
Application Number | 20120256181 13/158045 |
Document ID | / |
Family ID | 46965390 |
Filed Date | 2012-10-11 |
United States Patent
Application |
20120256181 |
Kind Code |
A1 |
SHIEH; Jia-Min ; et
al. |
October 11, 2012 |
POWER-GENERATING MODULE WITH SOLAR CELL AND METHOD FOR FABRICATING
THE SAME
Abstract
The invention discloses a power-generating module with solar
cell and method for fabricating the same. The power-generating
module includes a flexible substrate, a circuit and a solar cell.
Both of the circuit and the solar cell are formed on the flexible
substrate and are connected with each other, such that the solar
cell is capable of providing the power needed by the circuit for
operation.
Inventors: |
SHIEH; Jia-Min; (Hsinchu,
TW) ; Shen; Chang-Hong; (Hsinchu, TW) ; Huang;
Wen-Hsien; (Hsinchu, TW) ; Dai; Bau-Tong;
(Hsinchu, TW) ; Huang; Jung Y.; (Hsinchu, TW)
; Kuo; Hao-Chung; (Hsinchu, TW) |
Family ID: |
46965390 |
Appl. No.: |
13/158045 |
Filed: |
June 10, 2011 |
Current U.S.
Class: |
257/57 ;
257/E31.002; 438/59 |
Current CPC
Class: |
H01L 27/142 20130101;
Y02E 10/548 20130101; H01L 31/03926 20130101; H01L 31/18 20130101;
H01L 31/075 20130101 |
Class at
Publication: |
257/57 ; 438/59;
257/E31.002 |
International
Class: |
H01L 31/0248 20060101
H01L031/0248; H01L 31/18 20060101 H01L031/18 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 11, 2011 |
TW |
100112482 |
Claims
1. A power-generating module with solar cell, comprising: a
flexible substrate; a circuit unit, formed on the flexible
substrate; and a solar cell unit, formed on the flexible substrate
and coupled to the circuit unit, so as to provide the power needed
for the operation of the circuit unit.
2. The power-generating module with solar cell of claim 1, wherein
the flexible substrate is a PEN substrate, a PET substrate or a
polyimide substrate.
3. The power-generating module with solar cell of claim 1, wherein
the circuit unit is a thin film transistor.
4. The power-generating module with solar cell of claim 3, wherein
the thin film transistor further comprises: an active layer, formed
on the flexible substrate; a source electrode structure, formed on
the active layer; a drain electrode structure, formed on the active
layer; and a gate electrode structure, formed in between the source
electrode structure and the drain electrode structure.
5. The power-generating module with solar cell of claim 3, wherein
the electron mobility of the thin film transistor is about 1.1
cm.sup.2/V-s.
6. The power-generating module with solar cell of claim 1, wherein
the solar cell unit further comprises: a metallic layer, formed on
the flexible substrate; a first oxide layer, formed on the metallic
layer; a p-i-n multi-layer structure, formed on the first oxide
layer; a second oxide layer, formed on the p-i-n multi-layer
structure; a first conductive layer, formed on the second oxide
layer; and a second conductive layer, formed on the first oxide
layer.
7. The power-generating module with solar cell of claim 6, wherein
the first oxide layer is formed of transparent conducting oxide
(TCO), and the second oxide layer is formed of Indium Tin Oxide
(ITO).
8. The power-generating module with solar cell of claim 6, wherein
the p-i-n multi-layer structure is an hydrogenated amorphous
silicon structure.
9. The power-generating module with solar cell of claim 1, wherein
the photovoltaic conversion efficiency of the solar cell unit is
about 9.6%.
10. A method for fabricating a power-generating module with solar
cell, comprising the following steps of: providing a flexible
substrate; forming a solar cell unit on the flexible substrate by
using a high density plasma at a temperature lower than about
150.degree. C.; and forming a circuit unit on the flexible
substrate; wherein the solar cell unit is coupled to the circuit
unit, so as to provide the power needed for the operation of the
circuit unit.
11. The method of claim 10, wherein forming the solar cell unit
further comprises the following steps of: (a) forming a metallic
layer on the flexible substrate; (b) forming a first oxide layer on
the metallic layer; (c) forming a p-i-n multi-layer structure on
the first oxide layer by using the high density plasma at a
temperature lower than 150.degree. C.; (d) forming a second oxide
layer on the p-i-n multi-layer structure; (e) forming a first
conductive layer on the second oxide layer; and (f) forming a
second conductive layer on the first oxide layer.
12. The method of claim 11, wherein the p-i-n multi-layer structure
is a hydrogenated amorphous silicon structure.
13. The method of claim 11, further comprising the following steps
in between step (e) and step (f): (e') etching the p-i-n
multi-layer structure to expose at least a part of the first oxide
layer, and the second conductive layer of step (f) is formed on the
exposed part of the first oxide layer.
14. The method of claim 11, wherein step (c) further comprises the
following steps of: (c1) forming a n-type layer on the first oxide
layer under a first process condition, wherein the first process
condition comprises a process pressure between 600 and 1200 mTorr,
a process power between 30 and 60 W and a deposition rate between 2
and 4 A/s; (c2) forming an i-type layer on the n-type layer under a
second process condition, wherein the second process condition
comprises a process pressure between 600 and 1200 mTorr, a process
power between 15 and 40 W and a deposition rate between 1 and 2.5
A/s; and (c3) forming a p-type layer on the i-type layer under a
third process condition, wherein the third process condition
comprises a process pressure between 600 and 1200 mTorr, a process
power between 30 and 60 W and a deposition rate between 2 and 5
A/s.
15. The method of claim 14, wherein in step (c1), the n-type layer
is formed of a first reaction gas mixture, which comprises
SiH.sub.4, H.sub.2, PH.sub.3 and Ar, wherein the flow rate of
SiH.sub.4 is between 6 and 15 sccm, the flow rate of H.sub.2 is
between 100 and 250 sccm, the flow rate of PH.sub.3 is between 0.5
and 1.5 sccm, and the flow rate of Ar is between 100 and 200
sccm.
16. The method of claim 14, wherein in step (c2), the i-type layer
is formed of a second reaction gas mixture, which comprises
SiH.sub.4, H.sub.2 and Ar, wherein the flow rate of SiH.sub.4 is
between 10 and 20 sccm, the flow rate of H.sub.2 is between 100 and
250 sccm, and the flow rate of Ar is between 100 and 200 sccm.
17. The method of claim 14, wherein in step (c3), the p-type layer
is formed of a third reaction gas mixture, which comprises
SiH.sub.4, H.sub.2, B.sub.2H.sub.6 and Ar, wherein the flow rate of
SiH.sub.4 is between 6 and 15 sccm, the flow rate of H.sub.2 is
between 100 and 250 sccm, the flow rate of B.sub.2H.sub.6 is
between 0.5 and 1.5 sccm, and the flow rate of Ar is between 100
and 200 sccm.
18. The method of claim 11, wherein the first oxide layer is formed
of transparent conducting oxide (TCO), and the second oxide layer
is formed of Indium Tin Oxide (ITO).
19. The method of claim 10, wherein the flexible substrate is a PEN
substrate, a PET substrate or a polyimide substrate.
20. The method of claim 10, wherein the circuit unit is made of
inductive coupling plasma technology.
Description
FIELD OF THE INVENTION
[0001] The present invention is related to a power-generating
module with solar cell and method for fabricating the same, and
more particularly, the invention to a power-generating module that
integrates thin film solar cell and circuit unit and method for
fabricating the same.
BACKGROUND OF THE INVENTION
[0002] In highly e-oriented era, all the tools needed in human life
and work have integrated with some kinds of electronic components.
For example, computer, cellular phone, camera, automobile and
motorcycle, a variety of household appliance and manufacturing
equipment, etc. Although e-oriented life has brought great
convenience to human, due to the need of continuous power supply
for the operation of electronic components, use of electrical
power, such as battery or home/industrial level of DC or AC power
is also increased accordingly.
[0003] Under the situation of limited traditional energy and easy
generation of pollution, there is a need for new pollution-free
energy. Therefore, many related organizations have devoted to the
development of wind energy, tidal energy and solar energy.
Therefore, many kinds of related power generating products have
been developed, among them, the application in solar energy field
is the most eye-catching one. With the development of semiconductor
technology, a light and compact solar cell is now available in the
market, in the mean time, it is integrated with some electronic
products to provide the power needed for the operation of the
electronic products.
[0004] In addition, in order to simplify the process of electronic
product, reduce the manufacturing cost and expand the application
scope, flexible substrate has been gradually introduced into the
electronic product to replace traditional substrate. For example,
plastic substrate has been used to replace the glass substrate in
liquid crystal display to manufacture flexible display such as
electronic paper. Due to the limited volume of such electronic
products, if thin solar cells can be integrated therein, it will be
helpful to improve the entire design structure and extending the
utilization time.
[0005] However, the glass transition temperatures of the frequently
used flexible substrate today, such as poly ethylene naphthalate
(PEN) and poly ethylene terephthalate (PET) are 80.degree. C. and
120.degree. C. respectively.
[0006] This makes it difficult to take the high temperature in the
process of plasma-enhanced chemical vapor deposition (PECVD) for
the fabrication of solar cells. In addition, if the temperature of
the process of PECVD is reduced, for example, lower than
150.degree. C., then the photovoltaic conversion efficiency of the
solar cell will be very poor.
SUMMARY OF THE INVENTION
[0007] Accordingly, the scope of the invention is to provide a
power-generating module with solar cell to solve the
above-mentioned problems of the prior art.
[0008] In an aspect of the invention, the power-generating module
with solar cell includes: a flexible substrate, a circuit unit and
a solar cell unit. Wherein, both of the circuit unit and the solar
cell unit are formed on the flexible substrate and coupled to one
another, so that the solar cell unit can provide the power needed
for the operation of the circuit unit.
[0009] In one embodiment, the flexible substrate is polyethylene
naphthalate (PEN) substrate, polyethylene terephthalate (PET)
substrate or polyimide substrate. In one embodiment, the circuit
unit can be thin film transistor made by inductive coupling plasma
technology, and the electron mobility thereof can be about 1.1
cm.sup.2/V-s.
[0010] In one embodiment, the solar cell unit further comprises: a
first oxide layer, a p-i-n multi-layer structure, a second oxide
layer, a first conductive layer and a second conductive layer.
Wherein, the p-i-n multi-layer structure is formed on the first
oxide layer; the second oxide layer is formed on the p-i-n
multi-layer structure; the first conductive layer is formed on the
second oxide layer; and the second conductive layer is formed on
the first oxide layer.
[0011] In one embodiment, the first oxide layer is formed of
transparent conducting oxide (TCO), and the second oxide layer is
formed of Indium Tin Oxide (ITO). In one embodiment, the first
conductive layer and the second conductive layer are formed of
Aluminum. In one embodiment, the photovoltaic conversion efficiency
of the solar cell unit is about 9.6%.
[0012] Another scope of the invention is to provide a method for
fabricating a power-generating module with solar cell to solve the
above-mentioned problems of the prior art.
[0013] In an aspect of the invention, the method includes the
following steps of: providing a flexible substrate; forming a solar
cell unit on the flexible substrate by using a high density plasma
at a temperature lower than 150.degree. C.; and forming a circuit
unit on the flexible substrate; wherein the solar cell unit is
coupled to circuit unit to provide the power needed for the
operation of the circuit unit.
[0014] In one embodiment, the steps of forming the solar cell unit
include the steps of forming a p-type layer, an i-type layer and a
n-type layer sequentially, so as to form a p-i-n multi-layer
structure. In practice, the process condition of the p-type layer
includes a process pressure between 600 and 1200 mTorr, a process
power between 30 and 60 W and a deposition rate between 2 and 5
A/s. In addition, the reaction gas to form the p-type layer
includes SiH.sub.4 having a flow rate between 6 and 15 sccm;
H.sub.2 having a flow rate between 100 and 250 sccm; B.sub.2H.sub.6
having a flow rate between 0.5 and 1.5 sccm; and Ar having a flow
rate between 100 and 200 sccm.
[0015] In practice, the process condition of the i-type layer
include a process pressure between 600 and 1200 mTorr, a process
power between 15 and 40 W and a deposition rate between 1 and 2.5
A/s. In addition, the reaction gas to form the i-type layer
includes SiH.sub.4 having a flow rate between 10 and 20 sccm;
H.sub.2 having a flow rate between 100 and 250 sccm, and Ar having
a flow rate between 100 and 200 sccm.
[0016] In practice, the process condition of the n-type layer
includes a process pressure between 600 and 1200 mTorr, a process
power between 30 and 60 W and a deposition rate between 2 and 4
A/s. In addition, the reaction gas to form the n-type layer
includes SiH.sub.4 having a flow rate between 6 and 15 sccm;
H.sub.2 having a flow rate between 100 and 250 sccm; PH.sub.3
having a flow rate between 0.5 and 1.5 sccm, and Ar having a flow
rate between 100 and 200 sccm.
[0017] By using the high density plasma technology to form the
power-generating module with solar cell, the invention has the
following advantages of: low temperature growth, low ion
bombardment, high deposition rate and enlargement of the area of
the solar cell. Accordingly, the power-generating module with solar
cell of the invention can be successfully formed on the flexible
substrate to show high conversion efficiency and high electron
mobility.
[0018] For the advantages and spirit regarding the present
invention, further understanding can be achieved through the
following detailed description and attached drawings of the present
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 illustrates a cross-sectional view of the
power-generating module with solar cell according to one embodiment
of the invention.
[0020] FIG. 2 illustrates a flow chart of the method of fabricating
the power-generating module with solar cell based on one embodiment
of the invention.
[0021] FIG. 3 illustrates the flow chart of step S400 in FIG.
2.
[0022] FIGS. 4A, 4B and 4C illustrate respectively charts made
based on the p-type layer, i-type layer and n-type layer of one
embodiment of the invention.
[0023] FIGS. 5A and 5B illustrate the voltage, current density,
wavelength and quantum efficiency of the amorphous silicon thin
film solar cell unit of one embodiment of the invention, the solar
cell unit is formed by using high density plasma technology at a
process temperature of 140.degree. C.
DETAILED DESCRIPTION OF THE INVENTION
[0024] The invention provides a power-generating module with solar
cell and a method for fabricating the same. In the followings, the
embodiments and practical applications of the invention are
described in detail, so as to explain the features, spirit and
advantages of the invention.
[0025] Please refer to FIG. 1, which illustrates the
cross-sectional view of one embodiment of the power-generating
module with solar cell of the current invention. As shown in the
figure, the power-generating module with solar cell 1 of the
invention mainly includes a flexible substrate 10, a thin film
transistor 12 and a solar cell unit 14.
[0026] Wherein, both of the thin film transistor 12 and the solar
cell unit 14 are formed on the flexible substrate 10. In practice,
the flexible substrate 10 can be, but not limited to PEN substrate,
PET substrate or polyimide substrate. In addition, the thin film
transistor 12 of the embodiment can be replaced with any other
suitable circuit unit, such as an electronic sensor and an
electronic label, etc.
[0027] As shown in the figure, the thin film transistor 12 includes
an active layer 120, a source electrode structure 122, a drain
electrode structure 124, a gate electrode structure 126 and an
insulating structure 128. The active layer 120 is formed on the
flexible substrate 10; the source electrode structure 122 and the
drain electrode structure 124 are all formed on the active layer
120; and the gate electrode structure 126 is formed in between the
source electrode structure 122 and the drain electrode structure
124. The insulating structure 128 encloses the active layer 120,
the source electrode structure 122, the drain electrode structure
124 and the gate electrode structure 126. In addition, the thin
film transistor 12 can include several contact structures (not
shown), which are formed on the source electrode structure 122, the
drain electrode structure 124 and the gate electrode structure 126
respectively, and exposed out of the insulating structure 128. In
practice, the insulating structure 128 can be made of SiO.sub.2 or
other suitable material.
[0028] As shown in the figure, the solar cell unit 14 includes: a
metallic layer 140, a first oxide layer 142, a p-i-n multi-layer
structure 144, a second oxide layer 146, a first conductive layer
148a and a second conductive layer 148b.
[0029] Wherein, the metallic layer 140 is formed on the flexible
substrate 10, and the metallic layer 140 can be made of Aluminum or
other suitable material. The first oxide layer 142 is formed on the
metallic layer 140, and the first oxide layer 142 can be made of
transparent conducting oxide (TCO) or other suitable material.
[0030] The p-i-n multi-layer structure 144 is formed on the first
oxide layer 142. In addition, the p-i-n multi-layer structure 144
includes a n-type layer 144a, an i-type layer 144b and a p-type
layer 144c. In practice, the n-type layer 144a, the i-type layer
144b and the p-type layer 144c can be hydrogenated amorphous
silicon (a-Si:H) or other suitable material.
[0031] Second oxide layer 146 is formed on the p-i-n multi-layer
structure 144, and the second oxide layer 146 can be made of Indium
Tin Oxide (ITO) or other suitable material. In addition, the first
conductive layer 148a is formed on the second oxide layer 146, and
second conductive layer 148b is formed on the first oxide layer
142. In practice, the first conductive layer 148a and the second
conductive layer 148b can be made of Aluminum or other suitable
material.
[0032] Additionally, in practice, the solar cell unit 14 can be
coupled to the thin film transistor 12 through circuit (not shown).
The circuit can be a voltage and current control circuit, or other
suitable circuit.
[0033] Please refer to FIG. 2, which shows a flow chart of the
method of fabricating the power-generating module with solar cell
according to one preferred embodiment of the invention. As shown in
the figure, the method includes the following steps:
[0034] Step S300, providing a flexible substrate, which can be PET,
PEN, polyimide or other suitable substrate, as described above.
Step S400, forming a solar cell unit on the flexible substrate by
using a high density plasma at a temperature lower than 150.degree.
C. Step S500, forming a circuit unit on the flexible substrate, as
described above, the circuit unit can be thin film transistor or
other suitable circuit units. Step S600, coupling the solar cell
unit to the circuit unit, so that the solar cell unit can provide
the power needed for the operation of the circuit unit. Please note
that, in practice, the order of the above-mentioned steps can be
optionally changed, and is not limited to the embodiment.
[0035] Please refer to FIG. 3, which further illustrates a flow
chart of S400 of FIG. 2. As shown in the figure, step S400 can
further includes the following steps of:
[0036] Step S401, forming a metallic layer on the flexible
substrate. Step S402 forming a first oxide layer on the metallic
layer. In practice, the first oxide layer can be formed by
sputtering or other suitable method. Step 403, forming a n-type
layer, an i-type layer and a p-type layer on the first oxide layer
sequentially by using high density plasma at a temperature lower
than 150.degree. C., to form a p-i-n multi-layer structure.
[0037] Step 404, forming a second oxide layer on the p-i-n
multi-layer structure. In practice, the second oxide layer can be
formed by sputtering or other methods. Step S405, forming a first
conductive layer on the second oxide layer. Step S406, etching the
p-i-n multi-layer structure so as to expose at least a part of the
first oxide layer. Step S407, forming a second conductive layer
above the exposed part of the first oxide layer.
[0038] Please note that, step S406 can be carried out optionally,
or be replaced with other step(s). Additionally, in practice, the
first conductive layer and the second conductive layer can be
formed by electron gun or other suitable method.
[0039] The process conditions of the above steps will be described
in more detail as follows.
[0040] Please refer to table 1, which lists the process parameters
of the p-i-n multi-layer structure of the solar cell.
[0041] The process conditions of the n-type layer include a process
pressure between 600 and 1200 mTorr, a process power between 30 and
60 W, a process temperature between 60 and 150.degree. C., and a
deposition rate between 2 and 4 A/s. Meanwhile, in one embodiment,
the n-type layer can be formed of a reaction gas mixture including
SiH.sub.4, H.sub.2, PH.sub.3 and Ar, wherein the flow rate of
SiH.sub.4 is between 6 and 15 sccm, the flow rate of H.sub.2 is
between 100 and 250 sccm, the flow rate of PH.sub.3 is between 0.5
and 1.5 sccm, and the flow rate of Ar is between 100 and 200
sccm.
[0042] The process conditions of the i-type layer include a process
pressure between 600 and 1200 mTorr, a process power between 15 and
40 W, a process temperature between 60 and 150.degree. C. and a
deposition rate between 1 and 2.5 A/s. Meanwhile, in one
embodiment, the i-type layer can be formed of a reaction gas
mixture including SiH.sub.4, H.sub.2 and Ar, wherein the flow rate
of SiH.sub.4 is between 10 and 20 sccm, the flow rate of H.sub.2 is
between 100 and 250 sccm, and the flow rate of Ar is between 100
and 200 sccm.
[0043] The process conditions of the p-type layer include a process
pressure between 600 and 1200 mTorr, a process power between 30 and
60 W, a process temperature between 60 and 150.degree. C. and a
deposition rate between 2 and 5 A/s. Meanwhile, in one embodiment,
the p-type layer can be formed of a mixture of reaction gas
including SiH.sub.4, H.sub.2, B.sub.2H.sub.6 and Ar, wherein the
flow rate of SiH.sub.4 is between 6 and 15 sccm, the flow rate of
H.sub.2 is between 100 and 250 sccm, the flow rate of
B.sub.2H.sub.6 is between 0.5 and 1.5 sccm, and the flow rate of Ar
is between 100 and 200 sccm.
TABLE-US-00001 TABLE 1 Doping gas/flow SiH4:H2 rate Ar Pressure
Dep. rate Layer (sccm) (sccm) (sccm) (mTorr) power Thickness (A/s)
p 10:200 B2H6/1.3 200 900 52 12 3.1 i 15:150 -- 100 700 18 400 1.3
n 10:200 PH3/0.5 200 900 45 20 1.73
[0044] The characteristics of layers formed are illustrated
sequentially in FIG. 4A (p-type layer), FIG. 4B (i-type layer) and
FIG. 4C (n-type layer).
[0045] The process conditions of the second oxide layer include a
process pressure between 50 and 80 mTorr, a process power between
200 and 500 W, a process temperature between 80 and 150.degree. C.,
and a deposition rate between 1 and 2 A/s. In addition, the etching
conditions of step 406 include a process pressure between 5 and 30
mTorr, and CF.sub.4 with a flow rate between 150 and 200 sccm and
Ar with a flow rate between 50 and 100 sccm is used.
[0046] Please refer to FIGS. 5A and 5B, which shows, based on an
embodiment of the invention, the voltage, current density,
wavelength and quantum efficiency of an amorphous silicon thin film
solar cell unit (with p-i-n multi-layer structure having a
thickness of 400 nm) deposited by using high density plasma
technology at a process temperature of 140.degree. C. In addition,
the photovoltaic conversion efficiency of the amorphous silicon
thin film solar cell unit is measured as 9.6%.
[0047] In another embodiment, when the amorphous silicon solar cell
with the p-i-n multi-layer structure having a thickness of 300 nm
is fabricated under process temperatures of 140.degree. C.,
90.degree. C. and 60.degree. C. respectively, the photovoltaic
conversion efficiencies of the solar cell are 9.6%, 6.9% and 4.6%
respectively. In addition, from related experiments, the open
circuit voltage, fill factor, conversion efficiency and efficiency
spectrum of the solar cell are all shown to tend to be optimized
with the rising of temperature.
[0048] In addition, even if the process temperature is lowered to
60.degree. C., the dark saturation current of the amorphous silicon
thin film deposited by using inductive plasma coupling technology
can still be lower than 6.times.10.sup.-8 A/cm.sup.2. This proves
that even under low temperature, the defect density of the
amorphous thin film fabricated in the invention is still very
low.
[0049] Through the confirmation of experiment, the Si thin film
deposited by using the method of the invention can be evenly
deposited no matter on planarized or roughening substrate, and no
discontinuity or vacancy will be generated on the interface between
Si thin film and transparent conductive layer, so as to reach a
extreme broad band quantum efficiency spectrum (300 to 750 nm).
[0050] In practice, the thin film transistor of the invention can
be formed, at a process temperature of 140.degree. C., by using
inductive coupling plasma technology. The electron mobility of the
thin film transistor is measured to be about 1.1 cm2/V-s, and the
thin film transistor can have a very high driving current. In
addition, the thin film transistor can have a very low dangling
bond density, which results in a low sub-threshold swing and low
off-state current.
[0051] To sum up, because the power-generating module with solar
cell of the invention is formed by using high density plasma
technology, it has advantages such as low temperature growth, low
ion bombardment, high deposition rate and enlargement of the area
of the solar cell. Therefore, the power-generating module with
solar cell of the invention can be successfully formed on the
flexible substrate with characteristics such as high conversion
efficiency and high electron mobility.
[0052] While the foregoing is directed to embodiments of the
present invention, other and further embodiments of the invention
may be devised without departing from the basic scope thereof, and
the scope thereof is determined by the claims that follow.
* * * * *