A bromine and chlorine concurrently functionalized end group for benzo[1,2-<i>b</i>:4,5-<i>b</i>′]diselenophene-based non-fluorinated acceptors: a new hybrid strategy to balance the crystallinity and miscibility of blend films for enabling highly efficient polymer solar cells

Wan, Shi‐Sheng; Xu, Xiaopeng; Jiang, Zhao; Yuan, Jian; Mahmood, Asif; Yuan, Guizhou; Liu, Kaikai; Ma, Wei; Peng, Qiang; Wang, Jinliang

doi:10.1039/c9ta14070k

Cited by 57 publications

(55 citation statements)

References 83 publications

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“…Chlorination represents another common strategy utilized in adjusting the energy levels and molecular packing of organic semiconductors and achieved many promising results. [37][38][39][40][41][42][43] Compared with fluorine, the electronegativity of chlorine is weaker, however, chlorination has a stronger ability in modifying the materials energy levels owing to its empty 3d orbital. [44] Furthermore, the introduction of chlorine could impact molecular packing and thermal properties differently than fluorination due to chlorine's bigger atomic radius.…”

Section: Furthermore Non-covalent Intermolecular Interactions Such Amentioning

confidence: 99%

The Role of Demixing and Crystallization Kinetics on the Stability of Non‐Fullerene Organic Solar Cells

et al. 2020

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Organic solar cells (OSCs) are one of the most promising cost-effective technologies for utilizing solar energy with a short energy payback time and in semitransparent applications. [1-3] Bulk heterojunction OSCs comprising a donor and acceptor blend as the photoactive layer have achieved impressive improvements in power conversion efficiencies (PCEs) over the past 25 years. [4-7] Owing to the rapid development of high-performance non-fullerene small molecular acceptors (SMAs), PCE of over 15-17% has been achieved in various systems. [8-12] These promising results make non-fullerene OSCs competitive with other types of next-generation solar technology. Among start-of-the-art non-fullerene SMAs, the fused-ring electron acceptor named ITIC, comprising a indacenodithieno[3,2-b]-thiophene core and 2-(3-oxo-2,3-dihydroinden-1-ylidene)malononitrile end-groups, represents the most extensively studied SMA that achieved high performance with various donor polymers. [13-15] A family of high-performance ITIC derivatives was then designed and synthesized to modify the energy levels, light absorption, and molecular packing of the materials, as well as the morphology of the devices, which significantly boosted the performance of non-fullerene OSCs. [16-18] Generally, design rules for modifying energy levels and optical properties exist, but design rules for miscibility and stability are largely missing, [19-22] yet they are of vital importance to guarantee a long operational lifetime. While some conceptual understanding exists that stability must be related to the glass transition of the SMA and the polymer, [19,23-25] the relation of molecular design to the glass transition and crystallization, in general, is unknown and complex, due in part to the complex amphiphilic nature of the materials. One of the most widely used chemical modification approaches to modulate non-fullerene SMA characteristics is the introduction of electron-withdrawing halogen atoms, which has generated a number of high-performance acceptors. [26,27] Given that fluorine has the highest electronegativity, fluorination can effectively modify the highest occupied molecular orbital of organic semiconductors without introducing undesirable steric hindrance like other, more bulky electron-deficient groups. [28-30]

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Section: Furthermore Non-covalent Intermolecular Interactions Such Amentioning

confidence: 99%

The Role of Demixing and Crystallization Kinetics on the Stability of Non‐Fullerene Organic Solar Cells

et al. 2020

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“…The synthetic routes of TSeIC4Cl and TSeIC4Br were shown in the Scheme and the detailed syntheses were provided in Supporting Information. TSeIC4Cl and TSeIC4Br were synthesized by the Knoevenagel condensation reaction between the central unit TSe‐2CHO [ 86 ] and dichloro‐substituted IC end group ( IC2Cl ) [ 87 ] or dibromo‐substituted IC end group ( IC2Br ) [ 77 ] with isolated yields of 91% and 85%, respectively. Their exact chemical structures are confirmed by 1 H NMR, 13 C NMR, and MALDI‐TOF‐MS, which were shown in support information.…”

Section: Resultsmentioning

confidence: 99%

Tetrabromination versus Tetrachlorination: A Molecular Terminal Engineering of Nonfluorinated Acceptors to Control Aggregation for Highly Efficient Polymer Solar Cells with Increased V_oc and Higher J_sc Simultaneously

et al. 2020

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Polymer solar cells (PSCs) have achieved a huge breakthrough in the past 5 years with the combinational contributions from the developments of nonfullerene acceptors (NFAs), polymeric donors, and kind of redundant of device engineering. [1-12] Compared with traditional fullerene acceptors, AD A framework nonfullerene small molecular acceptors (NF-SMAs) have significant advantages in broader absorption range, tunable molecular structure and energy levels, and diversified donor materials for matching. [13-23] Therefore, many such typed NF-SMAs have been synthesized and become the mainstream materials for the development of high-efficiency PSCs. [24-36] Recently, the power conversion efficiencies (PCEs) of NF-SMAs-based PSCs have been sharply increased over 16% in single-junction binary and ternary devices, indicating their great potentials for further practical application. [37-57] NF-SMAs, such as ITIC and Y6, typically comprise an electron-rich fused core, side chain group, and electron-deficient terminal groups, and all of which can be modified by introducing functional groups or atoms to better understand the structureproperty relationship and improve the device performance of ITIC or Y6 series-based PSCs. [58,59] Molecular engineering on ending groups of NF-SMAs, typically, is the last synthetic step in the synthesis of NF-SMAs and mainly contributed to the intermolecular packing, which played a vital role in optimizing the electronic and morphological properties as well as in enhancing charge transport and device performance. [60-65] Halogenation at the core unit or at the end group of the NF-SMAs with different number of halogen atoms or in different substituted position/aromatic groups is a significantly effective strategy to modulate molecular energy levels and absorption range and improve the blend morphology and device performance. [66-80] Compared with the popular fluorinated or chlorinated IC functionalized NF-SMAs, although brominated NF-SMAs show lower synthesis cost and are much easier for

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“…Thanks to their easily modified chemical structures, the electrochemical, optoelectronic, and physical properties of the molecules can be tuned and optimized to achieve efficient donor and acceptor materials. [ 17–26 ] To date, the OSCs based on nonfullerene SMAs and polymer donors have demonstrated efficiencies of over 17%. [ 27–39 ]…”

Section: Figurementioning

confidence: 99%

Altering the Positions of Chlorine and Bromine Substitution on the End Group Enables High‐Performance Acceptor and Efficient Organic Solar Cells

Luo

Chen

et al. 2020

Advanced Energy Materials

113

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Molecular design of organic semiconductors plays an important role in development of organic solar cell (OSC) materials and devices. [1-6] It is generally believed that subtle structural changes could lead to significant variations in the optoelectronic properties and photovoltaic performance of organic semiconductors. In particular, many of such examples have been demonstrated in the area of nonfullerene small-molecule acceptors (SMAs), [7-16] which has been a major revolution of the OSC field in the past few years. Thanks to their easily modified chemical structures, the electrochemical, optoelectronic, and physical properties of the molecules can be tuned and optimized to achieve efficient donor and acceptor materials. [17-26] To date, the OSCs based on nonfullerene SMAs and polymer donors have demonstrated efficiencies of over 17%. [27-39] It is widely recognized that subtle changes in the chemical structure of organic semiconductors can induce dramatic variations in their optoelectronic properties and device performance, especially for the nonfullerene small-molecule acceptors (SMAs). For instance, halogenation of the end groups in the acceptordonor-acceptor-type SMAs is an effective strategy to modulate the properties of the end group and thus the entire SMA. While previous position modulations have focused on only one substituent, this study shows the development of three isomeric SMAs (BTP-ClBr, BTP-ClBr1, and BTP-ClBr2) via manipulating the position of two halogen substituents (chlorine and bromine) on the terminal unit. BTP-ClBr exhibits a blueshifted absorption, a shallower lowest unoccupied molecular orbital energy level, and a weaker crystallization tendency relative to BTP-ClBr1 and BTP-ClBr2. A power conversion efficiency (16.82%) and an excellent fill factor (FF) (0.79) are realized in the optimal PM6:BTP-ClBr organic solar cell device. The higher FF is consistent with the results of the characterization including a longer charge recombination lifetime, a faster photocurrent decay, a weaker bimolecular recombination, and a more favorable domain size for PM6:BTP-ClBr, which all originate from a subtle change in the substitution sites that strongly influences the physicochemical properties of the SMA.

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A bromine and chlorine concurrently functionalized end group for benzo[1,2-b:4,5-b′]diselenophene-based non-fluorinated acceptors: a new hybrid strategy to balance the crystallinity and miscibility of blend films for enabling highly efficient polymer solar cells

Abstract: The hybrid IC functionalized BDSe-2(BrCl):PM7-based PSCs exhibit the impressive PCE of 14.54%, which is the highest value in hybrid IC-functionalized acceptor-based binary organic solar cells.

Cited by 57 publications

References 83 publications

The Role of Demixing and Crystallization Kinetics on the Stability of Non‐Fullerene Organic Solar Cells

The Role of Demixing and Crystallization Kinetics on the Stability of Non‐Fullerene Organic Solar Cells

Tetrabromination versus Tetrachlorination: A Molecular Terminal Engineering of Nonfluorinated Acceptors to Control Aggregation for Highly Efficient Polymer Solar Cells with Increased V_oc and Higher J_sc Simultaneously

Altering the Positions of Chlorine and Bromine Substitution on the End Group Enables High‐Performance Acceptor and Efficient Organic Solar Cells

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A bromine and chlorine concurrently functionalized end group for benzo[1,2-b:4,5-b′]diselenophene-based non-fluorinated acceptors: a new hybrid strategy to balance the crystallinity and miscibility of blend films for enabling highly efficient polymer solar cells

Abstract: The hybrid IC functionalized BDSe-2(BrCl):PM7-based PSCs exhibit the impressive PCE of 14.54%, which is the highest value in hybrid IC-functionalized acceptor-based binary organic solar cells.

Cited by 57 publications

References 83 publications

The Role of Demixing and Crystallization Kinetics on the Stability of Non‐Fullerene Organic Solar Cells

The Role of Demixing and Crystallization Kinetics on the Stability of Non‐Fullerene Organic Solar Cells

Tetrabromination versus Tetrachlorination: A Molecular Terminal Engineering of Nonfluorinated Acceptors to Control Aggregation for Highly Efficient Polymer Solar Cells with Increased Voc and Higher Jsc Simultaneously

Altering the Positions of Chlorine and Bromine Substitution on the End Group Enables High‐Performance Acceptor and Efficient Organic Solar Cells

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Product

Resources

About

Tetrabromination versus Tetrachlorination: A Molecular Terminal Engineering of Nonfluorinated Acceptors to Control Aggregation for Highly Efficient Polymer Solar Cells with Increased V_oc and Higher J_sc Simultaneously