Efficient Polymer Solar Cells Based on Non-fullerene Acceptors with Potential Device Lifetime Approaching 10 Years

Du, Xiaoyan; Heumueller, Thomas; Gruber, Wolfgang; Classen, Andrej; Unruh, Tobias; Li, Ning; Brabec, Christoph J.

doi:10.1016/j.joule.2018.09.001

Cited by 403 publications

(417 citation statements)

References 39 publications

Supporting

Mentioning

386

Contrasting

Unclassified

Order By: Relevance

“…These observations from the R-SoXS and GIWAXS measurements, as well as the shape of the degradation graphs suggest that indeed demixing and crystallization occur at the same time. [59,75] We speculate that the good stability may result from either of two reasons: (i) The system is ideal-miscible, the initial optimized blend has mixed domains that are locally at thermodynamic equilibrium determined by the ideal miscibility, and crystal-free; (ii) The blend is vitrified. Given that the demixing is not extensive and still far from the thermodynamic limit, and that we also see deterioration in FF (to be discussed more fully below), we conclude that crystallization is a strong contributing factor.…”

Section: Discussionmentioning

confidence: 99%

“…[17,53,54] This nucleation would enhance growth of crystals due to the extra chemical potential of the SMA crystals, thus forming large crystals over time by depleting the mixed domains. [59] Nevertheless, as new systems are developed for higher efficiency, it is not clear if higher lifetime can also be achieved and any new hypomiscible polymer:nonfullerene SMA (NF-SMA) systems may suffer from the morphology instability driven by thermodynamics. [47] It has been reported that some nonfullerene acceptors exhibit higher thermal and oxidative stability than the widely explored fullerene acceptors.…”

mentioning

confidence: 99%

See 1 more Smart Citation

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

View full text Add to dashboard Cite

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...

show abstract

Section: Discussionmentioning

confidence: 99%

mentioning

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

View full text Add to dashboard Cite

show abstract

“…Organic solar cells (OSCs) are considered as the third generation photovoltaic technology with the advantages of light weight, low‐cost solution processing and mechanical flexibility . Benefitting from the rapid development of photoactive layer materials, the power conversion efficiency (PCE) of single‐junction OSC has exceeded 15%, showing great potential for the practical use of OSCs .…”

Section: Optical Properties and Electrochemical Properties Of The Cilmentioning

confidence: 99%

Tailoring and Modifying an Organic Electron Acceptor toward the Cathode Interlayer for Highly Efficient Organic Solar Cells

et al. 2019

View full text Add to dashboard Cite

With the rapid advance of organic photovoltaic materials, the energy level structure, active layer morphology, and fabrication procedure of organic solar cells (OSCs) are changed significantly. Thus, the photoelectronic properties of many traditional electrode interlayers have become unsuitable for modifying new active layers; this limits the further enhancement in OSC efficiencies. Herein, a new design strategy of tailoring the end‐capping unit, ITIC, to develop a cathode interlayer (CIL) material for achieving high power conversion efficiency (PCE) in OSCs is demonstrated. The excellent electron accepting capacity, suitable energy level, and good film‐forming ability endow the S‐3 molecule with an outstanding electron extraction property. A device with S‐3 shows a PCE of 16.6%, which is among the top values in the field of OSCs. More importantly, it is demonstrated that the electrostatic potential difference between the CIL molecule and the polymer donor plays a crucial role in promoting exciton dissociation at the CIL/active layer interface, contributing to additional charge generation; this is crucial for enhancement of the current density. The results of this work not only develop a new design strategy for high‐performance CIL, but also demonstrate a reliable approach of density functional theory (DFT) calculation to predict the effect of the CIL chemical structure on exciton dissociation in OSCs.

show abstract

“…The ITIC‐DM NFA with methyl group substitution showed an obviously increased charge recombination order after aging, while the ITIC‐2F with fluorine substitution showed a slight recombination order charge. The various charge recombination is caused by the different morphological defects or trap‐related recombination in active layer after aging because of their different chemical stability originating from the substitution effect . Recently, Chen et al constructed tandem OSC‐selecting PBDB‐T:F‐M and PTB7‐Th:O6T‐4F:PC 71 BM as the active layers of front and rear cells, respectively (molecular structure as shown in Scheme ).…”

Section: Stability Of Active Layer Materialsmentioning

confidence: 99%

Challenges to the Stability of Active Layer Materials in Organic Solar Cells

Wang

2020

Macromol. Rapid Commun.

View full text Add to dashboard Cite

In the past 20 years, organic solar cells (OSCs) have made great progress in pursuing high power‐conversion efficiencies, reaching the application threshold. Instead, device stability is becoming particularly important toward commercialization. There are many factors influencing the stability of OSCs, such as light, heat, humidity, oxygen, as well as device structure. Active layer materials, as the most critical functional layer in the devices, are greatly affected by these factors in terms of both efficiency and stability. Herein, it is desirable and urgent to summarize methods for obtaining active layer materials with long‐term stability, mainly focusing on the chemical structure and blending morphology. Meanwhile, the corresponding degraded mechanism of OSCs is concluded and analyzed. In this outlook, challenges for developing high‐performance and stable OSCs are discussed.

show abstract

Efficient Polymer Solar Cells Based on Non-fullerene Acceptors with Potential Device Lifetime Approaching 10 Years

Cited by 403 publications

References 39 publications

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

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

Tailoring and Modifying an Organic Electron Acceptor toward the Cathode Interlayer for Highly Efficient Organic Solar Cells

Challenges to the Stability of Active Layer Materials in Organic Solar Cells

Contact Info

Product

Resources

About