Layer-by-Layer-Processed Ternary Organic Solar Cells Using

Subscriber access provided by CORNELL UNIVERSITY LIBRARY

Article

Layer-by-Layer Processed Ternary Organic Solar Cells Using Perylene Bisimide as a Morphology-Inducing Component Na Zhu, Wenqiang Zhang, Qingwu Yin, Linlin Liu, Xiao-Fang Jiang, Zengqi Xie, and Yuguang Ma ACS Appl. Mater. Interfaces, Just Accepted Manuscript • Publication Date (Web): 04 May 2017 Downloaded from http://pubs.acs.org on May 6, 2017

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

ACS Applied Materials & Interfaces is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 20

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Applied Materials & Interfaces

Layer-by-Layer Processed Ternary Organic Solar Cells Using Perylene Bisimide as a MorphologyInducing Component Na Zhu,a,† Wenqiang Zhang,b,† Qingwu Yina, Linlin Liua, Xiaofang Jianga, Zengqi Xie,a,* Yuguang Ma a a

Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of

Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, P. R. China. b

State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Changchun

130012, P. R. China. †

These authors contributed equally to this work.

KEYWORDS: layer-by-layer, ternary, perylene bisimide, non-fullerene, morphology

ABSTRACT: A perylene bisimide (PBI-C4) with strong self-aggregation ability was used with PTB7 to form an under-lying morphology-inducing layer in organic solar cells. The PTB7:PC71BM spin coated atop of the preprocessed morphology-inducing thin layer showed enhanced domain size with better phase separation compared to conventional spin-coated on ZnO directly. The active layer’s proper aggregation morphology shows higher electrical

ACS Paragon Plus Environment

1


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 2 of 20

properties, results in 14% improvement in PCE (8.96% vs 7.85%). After replace the ZnO cathode interlayer with a photoconductive interlayer (ZnO:PBI-H), a maximum PCE of 9.47% is obtained, which is among the best device performance based on PTB7:PC71BM system.

INTRODUCTION Bulk heterojunction (BHJ) organic solar cells (OSCs) have emerged as a promising strategy for superiority in both outstanding power conversion efficiency (PCE) and industrialized lower cost for large-scale manufacturing. Great efforts have been earnestly spent to elevate the PCE of OSCs, such as optimize synthesis methods to new materials,1-8 developing novel device configuration, applying interfacial materials,9-14 and improving preparation technologies.15-16 OSCs with high performance are normally fabricated with appropriate morphology of the active layer to gain excellent electrical properties. Morphology control of the phase separation is critically important to good performance as nanoscale interpenetrating networks with appropriate aggregation, domain size, and interfacial area.17-20 It was demonstrated that introduce a certain ratio of small molecule with high crystallinity to active layer can vary the morphology of the active layer effectively.21 Recently, ternary blend BHJ OSCs containing either a third donor or a third acceptor are rising as a competitive candidate to break the PCE limitation by improving the light absorption range or strength of the final active layer.22-29 The classical way to prepare active layer of ternary OSCs at present is spin coating the mixed solution of three components directly. However, the morphology control with different ratio of the third component in the ternary system is a great challenge. An alternative layer-by-layer (LBL) solution-processed method has been reported, which possesses obvious advantages like easily controlled phase separation and component ratios as well as simple procession method.15-16


2

Page 3 of 20

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Up to now, various types of the third components have been used in ternary OSCs, such as polymers, fullerene derivatives and nano-crystals. Among them, perylene bisimide (PBI) derivatives show outstanding characteristics of high electron mobility, strong absorption ability, and high environmental / thermal stability, strong tendency to form ordered aggregation and also low-lying frontier energy levels, which have been reported as an important class of electron acceptor materials in binary OSCs.30-33 In recent years, three dimensional molecules by connecting two, three or four PBI units either on the bay-positions or on the imide-positions have been attracted much attention in order to develop high performance electron acceptors.34 The essential idea is to reduce the aggregation ability of PBI molecules to achieve nano-sized phase separation when blends with conjugated polymers. The PCE of the PBI based OSCs grows rapidly and is already up to 8.4%, similar or even higher than fullerene derivatives based OSCs.8 Herein, we report LBL processed highly efficient ternary OSCs, using a thin layer of PBI (PBI-C4): PTB7 (polythieno[3,4-b]-thiophene/benzodithiophene) as the under-lying morphology inducing layer in device. PBI-C4 possesses rather strong self-aggregation ability, which enables the active layer, PTB7: PC71BM ([6,6]-phenyl C71 butyric acid methyl ester) spin-coated atop of the preprocessed layer, showed enhanced domain size with better phase separation compared with it spin-coated on the ZnO directly. The proper aggregation morphology of the final active layer results in improved electrical properties. As a result, the LBL ternary OSC obtained 14% improvement in PCE relative to that of the binary OSC (8.96% vs 7.85%). When using a photoconductive cathode interlayer (ZnO:PBI-H) in device, a maximum PCE of 9.47% was obtained for PTB7:PC71BM based device. RESULTS AND DISCUSSION


3


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 4 of 20

The chemical structures of materials used in this work are shown in Chart 1, and the device configuration is shown in Figure 1a. The PTB7: PBI-C4 thin layer was fabricated on sol-gel derived ZnO thin film by spin-coating method from the dilute mixed solution (PTB7 of 1 mg/mL, PBI-C4 of 1.5 mg/mL). After thermal annealing at 150℃ for ten minutes, the PTB7:PC71BM active layer was spin coated atop of PTB7: PBI-C4 thin layer. The thickness of the binary active layer was 100 nm and the total thickness of PTB7:PC71BM and PTB7: PBI-C4 was 110 nm, so the thickness of PTB7: PBI-C4 thin layer was estimated to be around 10 nm in the LBL ternary system.

Chart 1. Chemical structures of PBI-C4, PTB7 and PC71BM.


4

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(b)

1.2

Normalized Absorption

Page 5 of 20

1.0

PBI-C4 solution PBI-C4 film PTB7 film PTB7:PBI-C4 film

0.8 0.6 0.4 0.2 0.0 400

500

600

700

800

Wavelength (nm)

Figure 1. (a) Device configuration of the LBL ternary OSC. (b) UV-Vis absorption spectra of PBI-C4 in solution, and the spin-coated PTB7, PBI-C4, PTB7: PBI-C4 films. UV-vis absorption of pure PBI-C4 in solution and the solid film was shown in Figure 1b. The absorption in thin film of PBI-C4 (λmax = 603nm) showed obvious bathochromic shift with respect to the momomeric state in solution (λmax = 578nm), which is attributed to the selfaggregation of PBI-C4 molecules promoted by intermolecular π-π stacking interactions. The absorption band of the aggregates (603 nm) keeps almost the same in the blending film of PTB7: PBI-C4 when spin-coated at the same conditions (Figure 1b), which clearly indicates the rather strong aggregation ability of PBI-C4. Indeed, it was possible to get large size single crystal of PBI-C4. Thus, the PTB7: PBI-C4 thin film was further used as the morphology inducer to form an ideal morphology of the active layer in the following work.


5


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 6 of 20

Figure 2. (a, b) AFM phase images of (a) binary and (b) LBL ternary blend films spin-coated on ITO/ZnO substrates. The scan size is 5um×5um. (c, d) TEM images of blends in (c) binary and (d) LBL ternary blend films, respectively.

The morphologies of PTB7:PC71BM active layer films spin-coated on ZnO and on ZnO/PTB7:PBI-C4 were investigated by atomic force microscope (AFM). As shown in Figure 2a and 2b, the PTB7:PC71BM layer on PTB7: PBI-C4 (LBL ternary blend) showed relatively larger phase separation when compared with that spin-coated on ZnO directly. This implied that, the underlying layer of PTB7:PBI-C4 accelerated the phase separation of PTB7:PC71BM. Transmission electron microscope(TEM) results further proved the microstructure inside the bulk thin film, which agreed well with the AFM results. As shown in Figure 2c and 2d, the bright regions relate to PTB7 domain and the dark regions related to acceptors–rich domains. The LBL


6

Page 7 of 20

ternary blends showed larger domain size compared with that of the binary film, which helps to improve the electrical properties. As shown in Figure S4, the PTB7:PC71BM layer spin-coated on PTB7: PBI-C4 showed decreased surface roughness relative to the control binary blend (rootmean-square roughness decreased from 2.01nm to 1.95nm), which optimized the interface contact between active layer and the anode. Indeed, the water contact angle increased from 47.03° for ZnO to 97.10° for PTB7: PBI-C4 (Figure S6), and thus the more hydrophobic surface help the PTB7:PC71BM solution to spread easier during procession and gain enhanced surface uniformity. The cross section of the ternary active layer was investigated by the scanning electron microscope (SEM). As shown in Figure S5, an integral layer was observed. XPS measurements were used to further evaluate the vertical distribution of the composition in LBL processed ternary active layer, and the results showed that PBI-C4 is rich near ZnO layer (Figure S8).

2

(b) 1000

0

Binary LBL Ternary

-3

100

Binary LBL Ternary

2

Current Density (mA/cm )

(a)

Current Density (mA/cm )

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


-6 -9 -12 -15

10 1 0.1 0.01 1E-3 1E-4 1E-5 1E-6

-18 0.0

0.2

0.4

0.6

0.8

-2

-1

0

1

2

Voltage (V)

Voltage (V)


7


(c) 80

60

EQE (%)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 8 of 20

40

Binary LBL Ternary

20

0 300

400

500

600

700

800

Wavelength (nm)

Figure 3. (a) Current density-voltage (J-V) characteristics of binary and LBL ternary blend solar cells under 1000 W / m2 AM 1.5G illumination. (b) J-V curves in the dark. (c) EQE curves.

Table 1. Photovoltaic Parameters of the Binary and LBL Ternary Blend OSCs. Solar cells

Voc (V)

Jsc (mA·cm-2)

FF (%)

PCE(%) a)

Binary

0.75±0.01

15.51±0.24

67.46±0.76

7.85±0.13 (8.07)

LBL Ternary

0.76±0.01

16.21±0.22

72.72±0.79

8.96±0.11 (9.18)

a)

The best PCEs are given in the brackets. b) The value in the table were achieved from 15 devices for each condition. The LBL ternary blend OSCs were fabricated with an inverted configuration of ITO/ZnO (30 nm)/PTB7: PBI-C4 (10 nm)/PTB7:PC71BM (100 m)/MoO3 (10 nm)/Al (100 nm) (Figure 2a). As references, device of ITO/ZnO (30 nm)/PTB7:PC71BM (100 m)/MoO3 (10 nm)/Al (100 nm) was also fabricated. The ratio between PTB7 and PBI-C4 in solution was 1:1.5 (w/w), which was used to prepare the morphology inducing layer. The concentration of PTB7:PC71BM was 10:15 mg/ml, which is the optimized weight radio for PTB7:PC71BM system. The corresponding photovoltaic performance parameters including open circuit voltage (Voc), short circuit current (Jsc), fill factor (FF) and PCE are summarized in Table 1. The representative current density versus voltage (J-V) characteristics of the inverted devices under AM 1.5G irradiation at


8

Page 9 of 20

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


1000W/m2 and in the dark are shown in Figure 3a and 3b. The corresponding external quantum efficiency (EQE) is given in Figure 3c. The LBL ternary blend solar cells exhibited an average PCE of 8.96% with a Voc of 0.76V, a Jsc of 16.21 mA·cm-2 and a FF of 72.72%, which is significantly better than the value of the reference binary device that showed typical PCE of 7.85% (VOC of 0.75V, JSC of 15.51 mA·cm-2 and FF of 67.46%). All the device parameters were improved by incorporating the PTB7: PBI-C4 morphology inducing layer. It should be noted that the FF value of the LBL ternary device was significantly increased to 72.72% relative to that of binary device (FF of 67.46%) that was probably due to the enhanced charge carriers transferring and extracting properties, which will be discuss below. The Jsc of the LBL ternary device was also increased due to the reduced recombination in the active layer that will be discussed below, and also might related to the enhanced light absorption of the active layer by the incorporation of the PTB7: PBI-C4 layer (Figure S7). The Voc in LBL ternary device is slightly increased than that of the binary device that is attributed the relatively higher LUMO level of PBI-C4 (-3.8 eV determined by cyclic voltammetry, Figure S3). We also fabricated devices using pre-processed thin layers of either PTB7:PC71BM or pristine PBI-C4 to replace the thin layer of PTB7: PBI-C4, and the device results are given in Figure S9 and Table S1. There is only slight difference for the performance between the devices using PTB7:PC71BM as the underlying layer (LBL binary device) and the control binary device, which come from the difference in thickness of the active layer. When using the pristine PBI-C4 thin layer as the underlying layer, the device performance is enhanced but lower than that obtained in the PTB7: PBI-C4 morphology inducing layer based LBL ternary device. The ternary solar cells were fabricated in classical way as reference by blending the three components with different ratios. The related photovoltaic performance are given in Figure S10


9


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 10 of 20

and Table S2. Device with 10% PBI-C4 gave the best performance, showing a VOC of 0.77V, a JSC of 16.66 mA·cm-2, a FF of 68.10% and a PCE of 8.73%. With the increased doping concentration of PBI-C4, the morphology of active layer changed a lot and very large size domains was observed when the doping concentration was over 50%. Compared with the conventional ternary device, our LBL fabrication method reported here is simple especially for the morphology optimization of the active layer.

Figure 4. J-V characteristics under dark of (a) electron-only device in configuration of ITO/ZnO/PTB7: PBI-C4 (0 or 10nm)/PTB7:PC71BM/PFN/Al, and (b) hole-only device in configuration of ITO/PEDOT: PSS/PTB7: PBI-C4 (0 or 10nm)/PTB7:PC71BM/Au in LBL ternary and binary OSC, respectively.

The charge carrier transport characteristics were calculated according to the Mott-Gurney law by the space charge limited current method. As shown in Figure 4, the LBL ternary blend based device showed a relatively higher charge carrier mobility (µe = 5.54 × 10-4 cm2 V-1 s-1, µh = 6.02 × 10-4 cm2 V-1 s-1) compared to the binary device (µe = 2.05 × 10-4 cm2 V-1 s-1, µh= 5.74 × 104

cm2 V-1 s-1). Charge transport is enhanced by the higher carrier mobility, which is attributed to

the optimized morphology of PTB7:PC71BM layer, and also PBI-C4 aggregates might provide


10

Page 11 of 20

channels for electronic transportation, leads to a more balanced charge transport and helps to improve the device fill factor. (b) Binary S=0.85 LBL Ternary S=0.96

-2

Current density (mA.cm )

(a)

Binary α=1.69 LBL Ternary α=1.35

0.75

Voc (V)

10

0.70

0.65 1 10

10

100

-2

Light density(mW.cm )

(c)

-2 Light density(mW.cm )

100

(d) 1.0

1.0

Binary LBL Ternary

0.8

Jsc (Normalized)

Voc (Normalized)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


0.6 0.4 0.2 0.0

Binary LBL Ternary

0.8 0.6 0.4 0.2 0.0

0

10

20

30

40

50

0

1

2

3

Time (us)

Time (us)

Figure 5. (a, b) Steady-state Jsc and Voc of the binary and LBL ternary blend solar cells against light intensity. (c, d) Transient photovoltage and photocurrent dependence on time of the binary and LBL ternary blend solar cells.

To understand why the LBL ternary devices showed better photovoltaic performance, the dependence of Jsc and Voc on light-intensity was investigated. In general, Jsc exhibits nearlinear dependence upon light intensity for the relationship of “Jsc∝(Plight)S ”, where Plight is light intensity and S is the exponential factor ( recombination parameter).36-38 The S can be related to


11


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 12 of 20

bimolecular recombination in the photo active layer and S value closer to 1 leads to the less bimolecular recombination. Figure 5a showed the Jsc - Plight relationship based on LBL ternary and binary devices, and the corresponding extracted S values are 0.96 and 0.85, respectively. The results indicated that the LBL ternary system has a lower bimolecular recombination, which corresponds well to the higher Jsc and FF in LBL ternary device. Figure 5b showed the relationship between Voc and Plight in LBL ternary and binary devices. The degree of trap-assisted recombination can be determined for the relationship following “Voc=αkBT/q.ln Plight + constant”, where kB is Boltzmann’s constant, T is temperature and q is elementary charge. In organic solar cells, α was observed to be 1 when bimolecular recombination occurs majorly and was concluded to be 2 when trap-assisted recombination takes the leading position.36-39 Our results show that the α of binary device was 1.69, while the α of LBL ternary device shows much smaller value of 1.35. The results indicated that less trapassisted recombination occurred in the LBL ternary system, which is clearly related to the incorporation of PTB7: PBI-C4 layer. The optimized morphology of the active layer reduced trap densities in LBL ternary OSCs. Transient photovoltage (TPV) and photocurrent (TPC) measurements in LBL ternary and binary devices were used to investigate more intrinsic characters of the charge recombination kinemics and charge extraction process. Figure 5c shows the TPV analysis. The LBL ternary OSCs show increased charge carrier lifetime relative to that in the control binary devices from 6.37 to 9.76 µs. The increased carrier decay time indicated that the suppressed recombination was obtained in device as discussed above. The transient photocurrent analysis are shown in Figure 5d, the charge extraction time was reduced for the LBL ternary device relative to the binary device from 0.63 to 0.51 µs. The enhanced charge extraction efficiency and increased


12

Page 13 of 20

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


carrier decay time contributes to the significantly improvement of FF and PCE in LBL ternary device. To investigate the best performance of the LBL ternary system, we used PBI-H to modify ZnO (photoconductive cathode interlayer) which was prepared in the same way of our previous report.11 As a result, a maximum PCE up to 9.47% (Voc of 0.76V, Jsc of 16.99 mA.cm-2 and FF of 73.89%) was achieved for the device based on the LBL ternary blend OSC. Figure S11 and Table S3 shows the corresponding performance of LBL ternary OSCs with photoconductive cathode interlayer. CONCLUSIONS In this work, LBL processed highly efficient ternary OSCs, using a thin layer of PTB7: PBIC4 as an under-lying morphology inducing layer was report. PBI-C4 possesses rather strong selfaggregation ability even blending with PTB7, which induce the active layer spin-coated atop it to form an ideal morphology with an increased charge separation and transport properties. A significantly enhanced PCE up to 9.47% was obtained after interface engineering, which is really high based on PTB7:PC71BM system. This work demonstrates a new promising way to fabricate high efficient ternary OSCs to introduce a morphology-inducing layer by LBL procession with a skillfully choose of the third component with proper aggregation ability.

ASSOCIATED CONTENT Supporting Information. Detailed experimental sections, cyclic voltammogram curves of PBIC4, structural characterization of PBI-C4, AFM of active layer, cross section SEM image of the ternary active layer, water contact angle images, UV-Vis absorption spectra, XPS information of LBL ternary active layer, J-V curves of device with different morphology inducing layer, J-V


13


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 14 of 20

curves of device with photoconductive cathode interlayer and ZnO, J-V curves of conventional ternary device. This material is available free of charge via the Internet at http://pubs.acs.org. AUTHOR INFORMATION Corresponding Author * E-mail: [email protected] Notes The authors declare no competing financial interest. ACKNOWLEDGMENT We thank the financial supported by National Natural Science Foundation of China (51373054, 51573055, 51521002), the National Basic Research Program of China (973 Program) (2014CB643504), Fundamental Research Funds for the Central Universities and Key Program of Guangzhou Scientific Research Special Project (201707020024). REFERENCES (1) Cui, C.; Guo, X.; Min, J.; Guo, B.; Cheng, X.; Zhang, M.; Brabec, C. J.; Li, Y., HighPerformance Organic Solar Cells Based on a Small Molecule with Alkylthio-Thienyl-Conjugated Side Chains without Extra Treatments. Adv. Mater. 2015, 27, 7469-7475. (2) Huo, L.; Liu, T.; Sun, X.; Cai, Y.; Heeger, A. J.; Sun, Y., Single-junction Organic Solar Cells Based on a Novel Wide-bandgap Polymer with Efficiency of 9.7%. Adv. Mater. 2015, 27, 2938-2944.


14

Page 15 of 20

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(3) Li, S.; Ye, L.; Zhao, W.; Zhang, S.; Mukherjee, S.; Ade, H.; Hou, J., Energy-Level Modulation of Small-Molecule Electron Acceptors to Achieve over 12% Efficiency in Polymer Solar Cells. Adv. Mater. 2016, 28, 9423-9429. (4) Zhou, Y.; Kurosawa, T.; Ma, W.; Guo, Y.; Fang, L.; Vandewal, K.; Diao, Y.; Wang, C.; Yan, Q.; Reinspach, J.; Mei, J.; Appleton, A. L.; Koleilat, G. I.; Gao, Y.; Mannsfeld, S. C.; Salleo, A.; Ade, H.; Zhao, D.; Bao, Z., High Performance All-polymer Solar Cell via Polymer Side-chain Engineering. Adv. Mater. 2014, 26, 3767-3772. (5)

Tang, A.; Zhan, C.; Yao, J., Comparative Study of Effects of Terminal Non-Alkyl

Aromatic and Alkyl Groups on Small-Molecule Solar Cell Performance. Adv. Energy Mater. 2015, 5, 1500059. (6) Zhang, Q.; Kan, B.; Liu, F.; Long, G.; Wan, X.; Chen, X.; Zuo, Y.; Ni, W.; Zhang, H.; Li, M.; Hu, Z.; Huang, F.; Cao, Y.; Liang, Z.; Zhang, M.; Russell, T. P.; Chen, Y., Small-molecule Solar Cells with Efficiency over 9%. Nat. Photonics 2014, 9, 35-41. (7) Li, H.; Earmme, T.; Ren, G.; Saeki, A.; Yoshikawa, S.; Murari, N. M.; Subramaniyan, S.; Crane, M. J.; Seki, S.; Jenekhe, S. A., Beyond Fullerenes: Design of Nonfullerene Acceptors for Efficient Organic Photovoltaics. J. Am. Chem. Soc. 2014, 136, 14589-14597. (8) Meng, D.; Sun, D.; Zhong, C.; Liu, T.; Fan, B.; Huo, L.; Li, Y.; Jiang, W.; Choi, H.; Kim, T.; Kim, J. Y.; Sun, Y.; Wang, Z.; Heeger, A. J., High-Performance Solution-Processed NonFullerene Organic Solar Cells Based on Selenophene-Containing Perylene Bisimide Acceptor. J. Am. Chem. Soc. 2016, 138, 375-380. (9) Liao, S. H.; Jhuo, H. J.; Cheng, Y. S.; Chen, S. A., Fullerene Derivative-doped Zinc Oxide Nanofilm as the Cathode of Inverted Polymer Solar Cells with Low-bandgap Polymer (PTB7Th) for High Performance. Adv. Mater. 2013, 25, 4766-4771.


15


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 16 of 20

(10) Nian, L.; Zhang, W.; Wu, S.; Qin, L.; Liu, L.; Xie, Z.; Wu, H.; Ma, Y. Perylene Bisimide as a Promising Zinc Oxide Surface Modifier: Enhanced Interfacial Compatibility for Highly Efficient Inverted Polymer Solar Cells. ACS Appl. Mater. Interfaces 2015, 7, 25821−25827. (11)

Nian, L.; Zhang, W.; Zhu, N.; Liu, L.; Xie, Z.; Wu, H.; Wurthner, F.; Ma, Y.,

Photoconductive Cathode Interlayer for Highly Efficient Inverted Polymer Solar Cells. J. Am. Chem. Soc. 2015, 137, 6995-6998. (12)

He, Z.; Zhong, C.; Su, S.; Xu, M.; Wu, H.; Cao, Y., Enhanced Power-conversion

Efficiency in Polymer Solar Cells Using an Inverted Device Structure. Nat. Photonics 2012, 6, 593-597. (13) Nian, L.; Zhou, J.; Zeng, K.; Wu, X.; Liu, L.; Xie, Z.; Huang, F.; Ma, Y., The Effect of Interfacial Diffusion on Device Performance of Polymer Solar Cells: a Quantitative View by Active-layer Doping. Sci. China Chem. 2015, 58, 317-322. (14) Tan, W.-Y.; Wang, R.; Li, M.; Liu, G.; Chen, P.; Li, X.-C.; Lu, S.-M.; Zhu, H. L.; Peng, Q.-M.; Zhu, X.-H.; Chen, W.; Choy, W. C. H.; Li, F.; Peng, J.; Cao, Y., Lending Triarylphosphine Oxide to Phenanthroline: a Facile Approach to High-Performance Organic Small-Molecule Cathode Interfacial Material for Organic Photovoltaics utilizing Air-Stable Cathodes. Adv. Funct. Mater. 2014, 24, 6540-6547. (15) Cheng, P.; Hou, J.; Li, Y.; Zhan, X., Layer-by-Layer Solution-Processed Low-Bandgap Polymer-PC61BM Solar Cells with High Efficiency. Adv. Energy Mater. 2014, 4, 1301349. (16) Lin, Y.; Ma, L.; Li, Y.; Liu, Y.; Zhu, D.; Zhan, X., Small-Molecule Solar Cells with Fill Factors up to 0.75 via a Layer-by-Layer Solution Process. Adv. Energy Mater. 2014, 4, 1300626.


16

Page 17 of 20

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(17) Zhou, E.; Cong, J.; Hashimoto, K.; Tajima, K., Control of Miscibility and Aggregation via the Material Design and Coating Process for High-performance Polymer Blend Solar Cells. Adv. Mater. 2013, 25, 6991-6996. (18)

Chen, D.; Liu, F.; Wang, C.; Nakahara, A.; Russell, T. P., Bulk Heterojunction

Photovoltaic Active Layers via Bilayer Interdiffusion. Nano Lett. 2011, 11, 2071-2078. (19) Huang, Y.; Kramer, E. J.; Heeger, A. J.; Bazan, G. C., Bulk Heterojunction Solar Cells: Morphology and Performance Relationships. Chem. Rev. 2014, 114, 7006-7043. (20)

Wang, Z.; Zhang, Y.; Zhang, J.; Wei, Z.; Ma, W., Optimized “Alloy-Parallel”

Morphology of Ternary Organic Solar Cells. Adv. Energy Mater. 2016, 6, 1502456. (21) Zhang, Y.; Deng, D.; Lu, K.; Zhang, J.; Xia, B.; Zhao, Y.; Fang, J.; Wei, Z., Synergistic Effect of Polymer and Small Molecules for High-performance Ternary Organic Solar Cells. Adv. Mater. 2015, 27, 1071-1076. (22) Savoie, B. M.; Dunaisky, S.; Marks, T. J.; Ratner, M. A., The Scope and Limitations of Ternary Blend Organic Photovoltaics. Adv. Energy Mater. 2015, 5, 1400891. (23) Ameri, T.; Khoram, P.; Min, J.; Brabec, C. J., Organic Ternary Solar Cells: A Review. Adv. Mater. 2013, 25, 4245-4266. (24)

Lu, L.; Kelly, M. A.; You, W.; Yu, L., Status and Prospects for Ternary Organic

Photovoltaics. Nat. Photonics 2015, 9, 491-500. (25) Nian, L.; Gao, K.; Liu, F.; Kan, Y.; Jiang, X.; Liu, L.; Xie, Z.; Peng, X.; Russell. T. P.; Ma, Y. 11% Efficient Ternary Organic Solar Cells with High Composition Tolerance via Integrated Near-IR Sensitization and Interface Engineering. Adv. Mater. 2016, 28, 8184–8190. (26) Liu, T.; Guo, Y.; Yi, Y.; Huo, L.; Xue, X.; Sun, X.; Fu, H.; Xiong, W.; Meng, D.; Wang, Z.; Liu, F.; Russell, T. P.; Sun, Y., Ternary Organic Solar Cells Based on Two Compatible


17


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 18 of 20

Nonfullerene Acceptors with Power Conversion Efficiency >10%. Adv. Mater. 2016, 28, 1000810015. (27) Baran, D.; Ashraf, R. S.; Hanifi, D. A.; Abdelsamie, M.; Gasparini, N.; Rohr, J. A.; Holliday, S.; Wadsworth, A.; Lockett, S.; Neophytou, M.; Emmott, C. J.; Nelson, J.; Brabec, C. J.; Amassian, A.; Salleo, A.; Kirchartz, T.; Durrant, J. R.; McCulloch, I., Reducing the Efficiency-stability-cost Gap of Organic Photovoltaics with Highly Efficient and Stable Small Molecule Acceptor Ternary Solar Cells. Nat. Mater. 2016, doi: 10.1038/nmat4797. (28) Gasparini, N.; Jiao, X.; Heumueller, T.; Baran, D.; Matt, G. J.; Fladischer, S.; Spiecker, E.; Ade, H.; Brabec, C. J.; Ameri, T., Designing Ternary Blend Bulk Heterojunction Solar Cells with Reduced Carrier Recombination and a Fill Factor of 77%. Nat. Energy 2016, 1, 16118. (29) Lu, L.; Xu, T.; Chen, W.; Landry, E. S.; Yu, L., Ternary Blend Polymer Solar Cells with Enhanced Power Conversion Efficiency. Nat. Photonics 2014, 8, 716-722. (30) Hartnett, P. E.; Timalsina, A.; Matte, H. S.; Zhou, N.; Guo, X.; Zhao, W.; Facchetti, A.; Chang, R. P.; Hersam, M. C.; Wasielewski, M. R.; Marks, T. J., Slip-stacked Perylenediimides as an Alternative Strategy for High Efficiency Nonfullerene Acceptors in Organic Photovoltaics. J. Am. Chem. Soc. 2014, 136, 16345-16356. (31) Liu, S. Y.; Wu, C. H.; Li, C. Z.; Liu, S. Q.; Wei, K. H.; Chen, H. Z.; Jen, A. K., A Tetraperylene Diimides Based 3D Nonfullerene Acceptor for Efficient Organic Photovoltaics. Adv. Sci. 2015, 2, 1500014. (32) Sharenko, A.; Proctor, C. M.; van der Poll, T. S.; Henson, Z. B.; Nguyen, T. Q.; Bazan, G. C.,

A

High-performing

Solution-processed

Small

Molecule:Perylene

Diimide

Bulk

Heterojunction Solar Cell. Adv. Mater. 2013, 25, 4403-4406.


18

Page 19 of 20

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(33) Lin, Y.; Wang, Y.; Wang, J.; Hou, J.; Li, Y.; Zhu, D.; Zhan, X., A Star-shaped Perylene Diimide Electron Acceptor for High-performance Organic Solar Cells. Adv. Mater. 2014, 26, 5137-5142. (34) Liu, Y.; Lai, J. Y. L.; Chen, S.; Li, Y.; Jiang, K.; Zhao, J.; Li, Z.; Hu, H.; Ma, T.; Lin, H.; Liu, J.; Zhang, J.; Huang, F.; Yu, D.; Yan, H., Efficient Non-fullerene Polymer Solar Cells Enabled by Tetrahedron-shaped Core Based 3D-structure Small-molecular Electron Acceptors. J. Mater. Chem. A 2015, 3, 13632-13636. (35) Xie, Z.; Stepanenko, V.; Fimmel, B.; Würthner, F., An Organogelator Design without Solubilizing Side Chains by Backbone Contortion of a Perylene Bisimide Pigment. Mater. Horiz. 2014, 1, 355-359. (36)

Cowan, S. R.; Roy, A.; Heeger, A. J., Recombination in Polymer-fullerene Bulk

Heterojunction Solar Cells. Phys. Rev. B 2010, 82, 245207. (37) Deibel, C.; Wagenpfahl, A.; Dyakonov, V., Origin of Reduced Polaron Recombination in Organic Semiconductor Devices. Phys. Rev. B 2009, 80, 075203. (38) Riedel, I.; Parisi, J.; Dyakonov, V.; Lutsen, L.; Vanderzande, D.; Hummelen, J. C., Effect of Temperature and Illumination on the Electrical Characteristics of Polymer–Fullerene BulkHeterojunction Solar Cells. Adv. Funct. Mater. 2004, 14, 38-44. (39) Koster, L. J. A.; Mihailetchi, V. D.; Ramaker, R.; Blom, P. W. M., Light Intensity Dependence of Open-circuit Voltage of Polymer:Fullerene Solar Cells. Appl. Phys. Lett. 2005, 86, 123509.


19


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 20 of 20

TOC GRAPHICS


20

Layer-by-Layer-Processed Ternary Organic Solar Cells Using

Recommend Documents