The progress and prospects of non-fullerene acceptors in ternary blend organic solar cells

Xu, Weidong; Gao, Feng

doi:10.1039/c7mh00958e

Cited by 126 publications

(84 citation statements)

References 125 publications

(163 reference statements)

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“…The highest occupied molecular orbital (HOMO) level and the lowest unoccupied molecular orbital level of DRCN5T are −5.32 and −3.64 eV, respectively, [51] which forms an energy cascade with PTB7-Th and PC 70 BM benefiting for charge separation and collection. [29] It is observed that DRCN5T displays complementary absorption with PTB7-Th and PC 70 BM from 450 to 700 nm. Hoping to investigate the impact of DRCN5T on the absorption behaviors, the binary PTB7-Th:DRCN5T and ternary PTB7-Th:DRCN5T:PC 70 BM blend films with different DRCN5T ratio are analyzed, as shown in Figure 1d and Figure S1 in the Supporting Information.…”

Section: Resultsmentioning

confidence: 94%

“…Besides understanding the internal mechanism of binary OSCs deeply, more and more efforts were paid to improve the performance of OSCs via tuning absorption and energy level of novel donor [4][5][6][7][8][9][10][11][12] and acceptor [13][14][15] materials, optimizing processing methods, [16][17][18][19] interfacial engineering, [20] and innovative device architectures. [28][29][30] Up to now, the best performance of ternary OSCs has been reported to be over 14%. The third component is usually combined with the host single-junction system to provide complementary absorption, tune recombination behavior, and optimize the morphology of active layer.…”

Section: Introductionmentioning

confidence: 99%

“…[25] Although both ternary OSCs and tandem OSCs could improve the power conversion efficiency (PCE) value to about 15%, the ternary strategy possessing simplicity of processing active layer exhibits great potential in R2R technology. [29] Especially, many researchers have realized the importance of miscibility in ternary OSCs, [28,[35][36][37] such as the appearance of Förster resonance energy transfer, [38] distribution of third additive on the interfaces of donor and acceptor, [39] formation of alloy with donor or acceptor, [36,37,40] etc. [6,[32][33][34] Unfortunately, most of the research work about how to select appropriate third additive is based on the trial and error strategy, which is a process of labor and time consumption.…”

Section: Introductionmentioning

confidence: 99%

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Miscibility Tuning for Optimizing Phase Separation and Vertical Distribution toward Highly Efficient Organic Solar Cells

et al. 2019

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Blending multidonor or multiacceptor organic materials as ternary devices has been recognized as an efficient and potential method to improve the power conversion efficiency of bulk heterojunction devices or single‐junction components in tandem design. In this work, a highly crystalline molecule, DRCN5T, is involved into a PTB7‐Th:PC 70 BM system to fabricate large‐area organic solar cells (OSCs) whose blend film thickness is up to 270 nm, achieving an impressive performance of 11.1%. The significant improvement of OSCs after adding DRCN5T is due to the formation of an interconnected fibrous network with decreased π–π stacking and enhanced domain purity, in addition to the optimized vertical distribution of PTB7‐Th and PC 70 BM, producing more effective charge separation, transport, and collection. The optimized morphology and performance are actually determined by the miscibility in different components, which can be quantitatively described by the Flory–Huggins interaction parameter of −0.80 and 2.94 in DRCN5T:PTB7‐Th and DRCN5T:PC 70 BM blends, respectively. The findings in this work can potentially guide the selection of an appropriate third additive for high‐performance OSCs for the sake of large‐area printing and roll‐to‐roll fabrication from the view of miscibility.

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Section: Resultsmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Miscibility Tuning for Optimizing Phase Separation and Vertical Distribution toward Highly Efficient Organic Solar Cells

et al. 2019

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“…However, such a quenched morphology is far from the binodal composition as shown in Figure 7a, and therefore its evolution toward the binodal is a spontaneous process that drives the system to a metastable equilibrium state. [73,74] This is a significant structural challenge. The aged samples also exhibited the formation of aggregation/crystals of IEICO-4F at room temperature as revealed in the GIWAXS data ( Figure 4).…”

Section: Discussionmentioning

confidence: 99%

Rational Strategy to Stabilize an Unstable High‐Efficiency Binary Nonfullerene Organic Solar Cells with a Third Component

Zhu

Gadisa

Peng

et al. 2019

Advanced Energy Materials

141

143

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decades, heuristic approaches have been successfully used to enhance the performance of OSCs, including synthesis of new donor and acceptor molecules, [5][6][7][8][9][10] optimization of the interface and morphology, [11][12][13][14][15] ternary blending, [16][17][18][19] and device engineering. [20][21][22][23] As a result, power conversion efficiency (PCE) of OSCs has surpassed 15% for single-layer bulkheterojunction systems. [24,25] As the PCE of OSCs is getting closer to the requirements for commercial applications and competing technology, the most efficient OSCs also need to perform consistently or maintain low efficiency loss throughout their lifetimes. [26][27][28] To make organic photovoltaics commercially viable and competitive, researchers have been making efforts on characterizing, understanding, and rationally engineering the long-term stability of OSC devices. [26,[29][30][31][32][33][34][35][36][37][38] Generally, the performance degradation of OSCs comes from the oxidation of electrodes, degradation of the interface layers, and changes in the morphology of the active layer. Among these factors, the oxidation of electrodes and the degradation of the interface layers are attributed to exposure to oxygen and moisture, [39,40] and these drawbacks can be largely prevented by encapsulation. [41,42] However, the intrinsic instability of active layer morphology driven by light, temperature, and thermodynamics cannot be prevented by encapsulation. In-depth studies were carried out to understand the stability of the active layers under multiple stresses. [43] For instance, McGehee and co-workers [29] reported that solar cells based on amorphous materials would suffer from open-circuit voltage (V OC ) burnin degradation resulted from the impact of light-induced traps, and this degradation can be reduced by using materials with high degree of crystallinity. Brabec group [33] demonstrated that the light-induced [6,6]-phenyl-C 61 -butyric acid methyl ester (PCBM) dimerization would lead to the short-circuit current density (J SC ) loss after aging, while this dimerization can be inhibited by a high degree of polymer-fullerene mixing and it can also be reduced via increasing the crystallization of the fullerene domains. Brabec and co-workers [34] found that burnin degradation driven by low miscibility is the major short-time Long device lifetime is still a missing key requirement in the commercialization of nonfullerene acceptor (NFA) organic solar cell technology. Understanding thermodynamic factors driving morphology degradation or stabilization is correspondingly lacking. In this report, thermodynamics is combined with morphology to elucidate the instability of highly efficient PTB7-Th:IEICO-4F binary solar cells and to rationally use PC 71 BM in ternary solar cells to reduce the loss in the power conversion efficiency from ≈35% to <10% after storage for 90 days and at the same time improve performance. The hypomiscibility observed for IEICO-4F in PTB7-Th (below the percolation threshold) leads to overpurific...

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“…On the contrary, the V OC of P2 ternary system hardly changes with the content of NCBDT‐4Cl, which could be correlated with the cascade structure model (see Tables S1 and S2 in the Supporting Information). [ 21,53–56 ] Obviously, the P1 and P2 binary PSCs exhibit comparable device performance and P2:LA1 even shows a higher PCE than P1:LA1, which indicates that biphenyl side group could be a good candidate for constructing high performance binary PSC than phenyl side group. However, distinct device performance of P1 and P2 based ternary PSCs were observed, which could be attributed to the disturbed micromorphology induced by the extended entanglement of polymer chains.…”

Section: Resultsmentioning

confidence: 99%

Significantly Enhanced Molecular Stacking in Ternary Bulk Heterojunctions Enabled by an Appropriate Side Group on Donor Polymer

Jiang

Wang

et al. 2020

Advanced Science

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Ternary strategy is a promising approach to broaden the photoresponse of polymer solar cells (PSCs) by adopting combinatory photoactive blends. However, it could lead to a more complicated situation in manipulating the bulk morphology. Achieving an ideal morphology that enhances the charge transport and light absorption simultaneously is an essential avenue to promote the device performance. Herein, two polymers with different lengths of side groups (P1 is based on phenyl side group and P2 is based on biphenyl side group) are adopted in the dual‐acceptor ternary systems to evaluate the relationship between conjugated side group and crystalline behavior in the ternary system. The P1 ternary system delivers a greatly improved power conversion efficiency (PCE) of 13.06%, which could be attributed to the intense and broad photoresponse and improved charge transport originating from the improved crystallinity. Inversely, the P2 ternary device only exhibits a poor PCE of 8.97%, where the decreased device performance could mainly be ascribed to the disturbed molecular stacking of the components originating from the overlong conjugated side group. The results demonstrate a conjugated side group could greatly determine the device performance by tuning the crystallinity of components in ternary systems.

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The progress and prospects of non-fullerene acceptors in ternary blend organic solar cells

Abstract: This review summarizes the advantages of non-fullerene acceptors and their applications in ternary blend organic solar cells.

Cited by 126 publications

References 125 publications

Miscibility Tuning for Optimizing Phase Separation and Vertical Distribution toward Highly Efficient Organic Solar Cells

Miscibility Tuning for Optimizing Phase Separation and Vertical Distribution toward Highly Efficient Organic Solar Cells

Rational Strategy to Stabilize an Unstable High‐Efficiency Binary Nonfullerene Organic Solar Cells with a Third Component

Significantly Enhanced Molecular Stacking in Ternary Bulk Heterojunctions Enabled by an Appropriate Side Group on Donor Polymer

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