TWI844057B - Photovoltaic device - Google Patents

Abstract

A photovoltaic device is disclosed and comprises a substrate, a firs electrode, a second electrode and an active layer. The first electrode is disposed on the substrate. The second electrode is disposed opposite to the first electrode. In addition, the active layer is disposed between the first electrode and the second electrode, and comprises an additive represented by the following formula (I). Moreover, on the basis of the total weight of the active layer, the content of the additive is ranged from 0.1 wt% to 10 wt%.

Wherein, R is defined in the specification.

Description

Photovoltaic installations

This disclosure relates to an additive, particularly an additive suitable for photovoltaic devices.

At present, the structure of most photovoltaic devices from bottom to top is substrate/anode/hole transport layer/active layer/electron transport layer/cathode, which is a traditional structure. Because the materials of the electron transport layer and the cathode are easily oxidized, ultraviolet curing glue is required for packaging, which greatly increases the production cost.

On the other hand, the most common photovoltaic device is the PM6:Y6 system, where PM6 is the donor material and Y6 is the acceptor material, but its efficiency and stability still need to be further improved; and affected by the booming development of personal devices in recent years, the demand for photovoltaic devices using indoor light sources (Indoor photovoltaics, IPVs) has also increased significantly, but its photoelectric conversion efficiency and stability still need to be improved.

Therefore, it is urgent to propose an improved additive and a photovoltaic device containing the same to eliminate or alleviate the above problems.

In view of this, the present disclosure proposes an additive and a photovoltaic device containing the same, by using an open cage fullerene material as an additive and improving the structure of the photovoltaic device to an inverted structure to enhance its photoelectric conversion efficiency and stability. Here, the inverted structure of the photovoltaic device refers to a structure of substrate/cathode/electron transport layer/active layer/hole transport layer/anode in order from bottom to top.

The photovoltaic device disclosed herein includes a substrate, a first electrode, a second electrode and an active layer, wherein the first electrode is disposed on the substrate, the second electrode is disposed opposite to the first electrode, the active layer is disposed between the first electrode and the second electrode and includes an additive as shown in the following formula (I), and compared with the total weight of the active layer, the content of the additive is between 0.1wt% and 10wt%:

Wherein R is H or C _1-6 alkyl.

In one embodiment of the present disclosure, R may be a C _1-4 alkyl group (eg, a C _1-3 alkyl group, a C _1-2 alkyl group). In one embodiment of the present disclosure, R may be a methyl group. However, the present disclosure is not limited thereto.

、 In one embodiment of the present disclosure, the active layer may further include an active layer material, wherein the active layer material may include at least one selected free

,

(PC₇₁BM)或

所組成之群 組，例如主動層材料可包括PM6：Y6、PM7：Y6、P3HT：PC₆₁BM、PM6：Y6：PC₆₁BM、PM6：IT-4F、PM6：IT-4F：PC₆₁BM、PM6：IT-4F：PC₇₁BM、PM6：PC₆₁BM、PM6：PC₇₁BM、PM7：IT-4F、PM7：IT-4F：PC₆₁BM、PM7：IT-4F：PC₇₁BM、PM7：PC₆₁BM、或PM7：PC₇₁BM。於本揭露的一實施例中，主動層材料可包括PM6及Y6。然而，本揭露不限於此。

(PC ₇₁ BM) or

The group formed, for example, active layer materials may include PM6:Y6, PM7:Y6, P3HT:PC ₆₁ BM, PM6:Y6:PC ₆₁ BM, PM6:IT-4F, PM6:IT-4F:PC ₆₁ BM, PM6:IT-4F:PC ₇₁ BM, PM6:PC ₆₁ BM, PM6:PC ₇₁ BM, PM7:IT-4F, PM7:IT-4F:PC ₆₁ BM, PM7:IT-4F:PC ₇₁ BM, PM7:PC ₆₁ BM, or PM7:PC ₇₁ BM. In one embodiment of the present disclosure, the active layer materials may include PM6 and Y6. However, the present disclosure is not limited thereto.

In one embodiment of the present disclosure, the content of the additive may be between 0.5wt% and 3wt%, preferably between 0.8wt% and 1.2wt%, more preferably between 0.9wt% and 1.1wt%, and most preferably about 1wt%, compared to the total weight of the active layer, but the present disclosure is not limited thereto.

In one embodiment of the present disclosure, the photovoltaic device may further include an electron transport layer, wherein the electron transport layer may be disposed between the substrate and the active layer. The material of the electron transport layer may include fullerene derivatives, titanium dioxide (TiO ₂ ), zinc oxide (ZnO), indium tin oxide (InSnO _x ), copper oxide (CuO _x ), aluminum oxide (Al ₂ O ₃ ), zirconium oxide (ZrO ₂ ), tin oxide (SnO ₂ ), tungsten oxide (WO ₃ ), niobium oxide (Nb ₂ O ₅ ), cadmium sulfide (CdS), cadmium selenide (CdSe), cadmium telluride (CdTe), bismuth sulfide (Bi ₂ S ₃ ), lead sulfide (PbS), indium phosphide (InP) or a combination thereof, but the present disclosure is not limited thereto.

In one embodiment of the present disclosure, the photovoltaic device may further include a hole transport layer, wherein the hole transport layer may be disposed between the active layer and the second electrode. The material of the hole transport layer may include molybdenum trioxide (MoO ₃ ), 2,2',7,7'-tetrakis-(N,N-di-p-methoxyphenylethylamine)9,9-spirobifluorene (spiro-OMeTAD), poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) (PEDOT-PSS), N,N'-di(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (TPD), polytrihexylpolythiophene (P3HT) or a combination thereof, but the present disclosure is not limited thereto.

In one embodiment of the present disclosure, the material of the first electrode may be a conductive transparent metal oxide, such as indium tin oxide (ITO), fluorine doped tin oxide (FTO), antimony doped tin oxide (ATO), aluminum doped zinc oxide (AZO), indium zinc oxide (IZO), gallium zinc oxide (GZO), indium tin zinc oxide (ITZO), indium gallium zinc oxide (IGZO) or a combination thereof.

In one embodiment of the present disclosure, the material of the second electrode may be a metal, such as gold, silver, copper, aluminum, palladium, nickel, titanium, chromium, molybdenum, alloys thereof, or combinations thereof.

In the present disclosure, the so-called "alkyl" includes linear and branched alkyl groups, for example, linear and branched _C1-6 alkyl groups, _C1-5 alkyl groups, _C1-4 alkyl groups, _C1-3 alkyl groups or _C1-2 alkyl groups; and specific examples thereof include, but are not limited to: methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, neopentyl, and hexyl.

The following will be accompanied by drawings and detailed descriptions to make other purposes, advantages, and novel features of the present invention more obvious.

1: Photovoltaic device

10: Substrate

11: First electrode

12: Second electrode

13: Active layer

14:Electron transmission layer

15: Hole transport layer

Figure 1 is a schematic diagram of a photovoltaic device according to an embodiment of the present disclosure.

Figure 2 shows the normalized efficiency of the photovoltaic devices of the comparison example and Examples 1 to 3 at room temperature.

Figure 3 shows the normalized efficiency of the photovoltaic devices of the comparison example and Examples 1 to 3 after annealing at 80°C.

Figure 4 shows the current density-voltage curves of the photovoltaic devices of the comparison example and embodiments 1 to 3.

FIG. 5 is a comparison of the current density and voltage (J _sc -V) characteristic curves under different lighting conditions.

FIG. 6 is a characteristic curve of current density and voltage (J _sc -V) of Example 2 under different lighting conditions.

Different embodiments of the present invention are provided below. These embodiments are used to illustrate the technical content of the present invention, rather than to limit the scope of the present invention. A feature of an embodiment can be applied to other embodiments through appropriate modification, replacement, combination, and separation.

It should be noted that, in this document, unless otherwise specified, "having an element" is not limited to having a single element, but may have one or more elements.

In addition, in this article, unless otherwise specified, ordinal numbers such as "first" and "second" are only used to distinguish multiple components with the same name, and do not indicate the existence of a hierarchy, level, execution order, or process order between them. A "first" component and a "second" component may appear together in the same component, or appear separately in different components. The existence of a component with a larger ordinal number does not necessarily indicate the existence of another component with a smaller ordinal number.

In this document, unless otherwise specified, the so-called feature A "or" or "and/or" feature B means that A exists alone, B exists alone, or A and B exist at the same time; the so-called feature A "and" or "and" or "and" feature B means that A and B exist at the same time; the so-called "include", "include", "have", "contain" means including but not limited to these.

In addition, in this article, the terms "upper", "lower", "left", "right", "front", "back", or "between" are only used to describe the relative positions between multiple components, and the interpretation can be extended to include translation, rotation, or mirroring.

In addition, in this document, unless otherwise specified, "an element is on another element" or similar descriptions do not necessarily mean that the element contacts the other element.

In addition, in this article, "preferable" or "better" is used to describe optional or additional elements or features, that is, these elements or features are not necessary and may be omitted.

In addition, in this document, unless otherwise specified, a numerical value may cover a range of ±10% of the numerical value, in particular, a range of ±5% of the numerical value. Unless otherwise specified, a numerical range is composed of multiple sub-ranges defined by the lower end point, the lower quartile, the median, the upper quartile, and the upper end point.

Preparation method of open cage fullerene 8OC ₆₀ Me

[Reaction 1]

Take 0.714g of 3,6-di(thiophene-2-yl)-1,2,4,5-tetrazine 1 and 0.492g of 5-hexenoic acid methyl ester 2 and dissolve them in 30mL of o-xylene, place them in a high pressure tube, heat to 140℃ and react for 24 hours. Inject oxygen into the light orange liquid after the reaction for 15 minutes, and heat to react for another 24 hours. Use silica gel with hexane/ethyl acetate (1/1) as the eluent to purify the crude product after the above reaction by column chromatography to obtain 739mg of light yellow solid (yield 74%) compound 3, with a melting point between 57℃ and 60℃.

The hydrogen spectrum data of compound 3 are as follows: 19.4-2.04 (m, 2H), 2.42 (t, J = 7.1 Hz, 2H), 2.91 (t, J = 8.1 Hz, 2H), 3.68 (s, 3H), 7.07-7.14 (m, 2H), 7.48-7.63 (m, 5H)

The carbon spectrum data of compound 3 are as follows: 23.6, 31.9, 33.3, 51.8, 122.5, 126.0, 127.8, 127.9, 128.0, 128.6, 128.8, 137.1, 140.2, 140.3, 152.9, 153.1, 172.5

The IR spectrum of compound 3 is as follows: 1731cm ^-1

The mass spectrum of compound 3 is as follows: 344.0649

Next, 728.6 mg of carbon 60 and 420 mg of the above compound 3 were dissolved in 50 mL of 1-chloronaphthalene, heated to 270°C under argon and refluxed for 48 hours. The purple-red crude product after the above reaction was purified by rapid column chromatography using silica gel and toluene/n-hexane (2/1) as the eluent to obtain 330 mg of unreacted carbon 60. Next, toluene was used as the eluent to obtain brown solid (yield 45%) open cage fullerene 8OC ₆₀ Me.

The hydrogen spectrum of 8OC ₆₀ Me is as follows: 1.69-1.89 (m, 2H), 1.95-2.09 (b, 2H), 2.31 (t, J = 7.5Hz, 2H), 3.64 (s, 3H), 6.18 (s, 1H), 7.11 (dd, J = 3.5Hz, 5.1Hz, 2H), 7.42-7.55 (m, 4H)

The carbon spectrum data of 8OC ₆₀ Me are as follows: 23.1, 32.2, 33.5, 51.5, 51.9, 54.1, 124.5, 125.0, 125.5, 125.6, 125.8, 126.2, 126.3, 126.4, 126.6, 126.8, 127.0, 127.5, 127.7, 128.1, 129.7, 130.2, 134.7, 134.8, 135.3, 135.8, 136.9, 137.1, 137.5, 137.8, 138.1, 138.3, 140.2, 140.3, 140.4, 140. 6,140.7,140.81,140.84,140.89,142.1,142.4,143.2,143.6,143.7,143.8,143.9,144.1,144.11,144.13,144.19,144.21,144.3,144.39,144.42,144.59,144.61,144.8,144.9,145.0,145.4,145.6,145.87,145.91,149.1,149.3,150.2,151.8,153.8,173.5

The IR spectrum of 8OC ₆₀ Me is as follows: 1714cm ^-1

The mass spectrum of 8OC ₆₀ Me is as follows: 1036.44

Structure of photovoltaic device

Figure 1 is a schematic diagram of a photovoltaic device according to an embodiment of the present disclosure.

As shown in FIG. 1 , the present disclosure provides a photovoltaic device 1, comprising a substrate 10, a first electrode 11, a second electrode 12, an active layer 13, an electron transport layer 14 and a hole transport layer 15, wherein the first electrode 11 is disposed on the substrate 10, the second electrode 12 is disposed opposite to the first electrode 11, the active layer 13 is disposed between the first electrode 11 and the second electrode 12, the electron transport layer 14 is disposed between the first electrode 11 and the active layer 13, and the hole transport layer 15 is disposed between the active layer 13 and the second electrode 12.

Preparation method of photovoltaic device

In an ultrasonic water bath, the patterned indium tin oxide (ITO) glass substrate (i.e., the first electrode 11 disposed on the substrate 10) is cleaned with warm detergent, deionized water, acetone, and isopropyl alcohol for 20 minutes. The thickness of ITO is 260±20 nanometers. Then, the indium tin oxide (ITO) glass substrate is treated with ultraviolet ozone for 5 minutes. A zinc oxide nanoparticle (ZnO nanoparticle) solution is dropped onto the substrate and coated by rotation at a speed of 3000 rpm for 30 seconds. Subsequently, the glass substrate coated with the zinc oxide layer is baked at 180°C on a heating plate for 20 minutes to form a zinc oxide (ZnO) layer (i.e., the electron transport layer 14). The thickness of the electron transport layer 14 is 30 nm. The mixed active solution, PM6:Y6 (D/A 1:1.2), was dissolved in chloroform (16 mg/mL) containing a solvent additive 1-chloronaphthalene (CN) (0.5% v/v) and different proportions of 8OC ₆₀ Me prepared according to the above method, and then dropped onto the zinc oxide layer and spin-casted at 3000 rpm for 30 seconds to form the active layer 13. The thickness of the active layer 13 is 100 nm. Finally, 3 nm of molybdenum oxide (MoO ₃ ) was thermally evaporated in a vacuum chamber at a basic pressure of 3×10 ^-7 Torr as the hole transport layer 15, and 100 nm of metal silver (Ag) was thermally evaporated as the second electrode 12. The effective area of the device is 0.10 cm ² .

Implementation Example 1

In this embodiment, a photovoltaic device 1 is prepared according to the above preparation method, wherein the first electrode 11 of the photovoltaic device 1 is ITO, the electron transport layer 14 is zinc oxide, the active layer 13 is PM6:Y6 containing 0.5wt% 8OC ₆₀ Me, the hole transport layer 15 is molybdenum oxide and the second electrode 12 is metallic silver.

Example 2

This embodiment is similar to Embodiment 1, except that the active layer 13 is PM6:Y6 containing 1 wt% 8OC ₆₀ Me.

Example 3

This embodiment is similar to Embodiment 1, except that the active layer 13 is PM6:Y6 containing 3 wt % 8OC ₆₀ Me.

Comparison example

This comparative example is similar to the embodiment 1, except that the active layer 13 only includes PM6:Y6 but does not include 8OC ₆₀ Me.

Efficacy

Figure 2 shows the normalized efficiency of the photovoltaic devices of the comparative example and Examples 1 to 3 at room temperature. Figure 3 shows the normalized efficiency of the photovoltaic devices of the comparative example and Examples 1 to 3 after annealing at 80°C.

As shown in Figure 2, the normalized efficiency of photovoltaic devices with different active layers at room temperature is compared. Compared with the comparative example, it can be found that the photovoltaic devices of Examples 1 to 3 have significantly improved stability. At room temperature, the normalized efficiency (Normalized PCE) of the comparative example dropped to 90% within 50 hours of testing, and dropped to 80% within 500 hours of testing. However, the normalized efficiency of the photovoltaic devices of Examples 1 to 3 remained above 92% within 500 hours of testing, and the normalized efficiency of the photovoltaic device of Example 2 remained at 99.4% under the same test conditions.

In addition, as shown in FIG3, the normalized efficiency of photovoltaic devices with different active layers at an annealing temperature of 80°C is compared. When the annealing temperature is 80°C, the normalized efficiency of the photovoltaic device of the comparative example drops to 89.5% within 3 hours of testing, and drops to 73.5% within 45 hours of testing; however, the normalized efficiency of the photovoltaic devices of Examples 1 to 3 is maintained at more than 85% within 45 hours of testing, and the normalized efficiency of the photovoltaic device of Example 2 is maintained at 91.7% within 20 hours of testing, and maintained at 91.0% within 45 hours of testing. It can be seen that, compared with the comparative example, Examples 1 to 3 of the present disclosure have significantly improved thermal stability. More specifically, adding open cage fullerene 8OC ₆₀ Me to PM6:Y6 can effectively improve the thermal stability of photovoltaic devices.

On the other hand, as shown in Table 1 below, please refer to Figure 4, which compares the device parameters of photovoltaic devices with different active layers under AM 1.5G (100mW cm ^-2 ) illumination. Compared with the comparative example, it can be found that the photovoltaic device of Example 2 has better power conversion efficiency. The PCE _max of Example 2 is 16.5%, the PCE is 16.2%, _{the Jsc} is 27.3mA/ ^cm2 , and the fill factor (FF) is 70.4%. The PCE _max of Example 2 is about 10% higher than the PCE _max of the comparative example. In addition, _the Jsc value of Example 2 is also higher than that of the comparative example. It can be seen that adding 1wt% 8OC ₆₀ Me to PM6:Y6 helps to improve the power conversion efficiency of the photovoltaic device.

Table 1 Device parameters of the photovoltaic devices of the comparative example and embodiments 1 to 3.

As shown in Tables 2 and 3 below, please refer to Figures 5 and 6, which compare the device performance of photovoltaic devices with different active layers under different indoor light sources. It can be found that when the light intensity increases from 200 lux to 2000 lux, J _sc , V _oc and fill factor (FF) will increase, thereby helping to improve the PCE of the photovoltaic device. Among them, the PCE _max of the photovoltaic device of Example 2 at 1600 lux is 30.0%, which is higher than the PCE _max of the comparison example under the same conditions (PCE _max is 23.5%). It can be seen that the photovoltaic device made by adding open cage fullerene 8OC ₆₀ Me as an additive in the active layer has considerable application potential in building integrated solar (BIPV) systems or indoor photovoltaic devices (IPV).

Table 2 Device performance of the PM6:Y6 system photovoltaic device (comparison example) under different lighting conditions.

Table 3 Device performance of the photovoltaic device of PM6:Y6 containing 1 wt % 8OC ₆₀ Me (Example 2) under different illumination conditions.

In summary, the present disclosure uses the open cage fullerene 8OC ₆₀ Me as an additive to improve the photoelectric conversion efficiency and thermal stability, and can provide excellent photoelectric conversion efficiency in an indoor light source environment. Therefore, the present disclosure uses the open cage fullerene 8OC ₆₀ Me as an additive in the active layer to make a photovoltaic device with considerable potential for use in building integrated solar (BIPV) systems or indoor photovoltaic devices (IPV) that are applied to general sunlight or indoor light sources, and can greatly expand the application field of photovoltaic devices.

Although the present invention has been described through a number of embodiments, it should be understood that many other possible modifications and changes may be made without departing from the spirit of the present invention and the scope of the patent application.

1: Photovoltaic device

10: Substrate

11: First electrode

12: Second electrode

13: Active layer

14:Electron transmission layer

15: Hole transport layer

Claims (10)

A photovoltaic device comprises: a substrate; a first electrode disposed on the substrate; a second electrode disposed opposite to the first electrode; and an active layer disposed between the first electrode and the second electrode and comprising an additive as shown in the following formula (I), wherein the content of the additive is between 0.1wt% and 10wt% compared to the total weight of the active layer:

Wherein R is H or C _1-6 alkyl. The photovoltaic device as described in claim 1, wherein R is a C _1-4 alkyl group. A photovoltaic device as described in claim 1, wherein R is a methyl group. The photovoltaic device as described in claim 1, wherein the active layer further comprises an active layer material, and the active layer material comprises at least one selected from the group consisting of PM6, PM7, Y6, P3HT, PC ₆₁ BM, PC ₇₁ BM or IT-4F. A photovoltaic device as described in claim 4, wherein the active layer material includes PM6 and Y6. A photovoltaic device as described in claim 1, wherein the content of the additive is between 0.5wt% and 3wt% compared to the total weight of the active layer. A photovoltaic device as described in claim 6, wherein the content of the additive is between 0.8wt% and 1.2wt% compared to the total weight of the active layer. The photovoltaic device as described in claim 1 further includes an electron transport layer, wherein the electron transport layer is disposed between the substrate and the active layer. The photovoltaic device as described in claim 1, wherein the material of the first electrode includes ITO, FTO, ATO, AZO, IZO, GZO, ITZO, IGZO or a combination thereof. The photovoltaic device as described in claim 1, wherein the material of the second electrode includes gold, silver, copper, aluminum, palladium, nickel, titanium, chromium, molybdenum, alloys thereof or combinations thereof.

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