An Easily Accessible Isoindigo-Based Polymer for High-Performance Polymer Solar Cells

Wang, Ergang; Ma, Zaifei; Zhang, Zhen; Vandewal, Koen; Henriksson, Patrik; Inganäs, Olle; Zhang, Fengling; Andersson, Mats R.

doi:10.1021/ja206610u

Cited by 366 publications

(323 citation statements)

References 42 publications

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“…, which more than compensated for a decrease in V oc to 0.70 V. 9,21 Evidently, despite the similar chemical structures a very different photovoltaic performance is obtained, which necessitates an in-depth investigation of relevant structure-property relationships of these oligothiophene-isoindigo polymers.…”

Section: à2mentioning

confidence: 99%

Structure–property relationships of oligothiophene–isoindigo polymers for efficient bulk-heterojunction solar cells

Sun

Himmelberger

et al. 2014

Energy Environ. Sci.

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110

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A series of alternating oligothiophene (nT)-isoindigo (I) copolymers (PnTI) were synthesized to investigate the influence of the oligothiophene block length on the photovoltaic (PV) properties of PnTI:PCBM bulkheterojunction blends. Our study indicates that the number of thiophene rings (n) in the repeating unit alters both polymer crystallinity and polymer-fullerene interfacial energetics, which results in a decreasing open-circuit voltage (V oc ) of the solar cells with increasing n. The short-circuit current density (J sc ) of P1TI:PCBM devices is limited by the absence of a significant driving force for electron transfer. Instead, blends based on P5TI and P6TI feature large polymer domains, which limit charge generation and thus J sc . The best PV performance with a power conversion efficiency of up to 6.9% was achieved with devices based on P3TI, where a combination of a favorable morphology and an optimal interfacial energy level offset ensures efficient exciton separation and charge generation. The structureproperty relationship demonstrated in this work would be a valuable guideline for the design of high performance polymers with small energy losses during the charge generation process, allowing for the fabrication of efficient solar cells that combine a minimal loss in V oc with a high J sc . Broader contextPolymer solar cells (PSCs) have emerged as promising candidates for low-cost, environmentally friendly energy conversion. However, a low power conversion efficiency (PCE) is still the main bottleneck for their commercial applications. In order to further improve their PCE, a detailed understanding of the underlying structure-property relationships that govern these materials is crucial. In this work, a series of alternating oligothiophene (nT)-isoindigo (I) copolymers (PnTI) were synthesized to investigate the inuence of the oligothiophene block length on the photovoltaic (PV) properties of PnTI:PCBM bulk-heterojunction blends. The driving force for the PSCs can be ne-tuned in a small range of 0-0.1 eV by changing the conjugated length of the oligothiophene block. This is a valuable guideline for polymer design to achieve high-efficiency PSCs with optimum photovoltage and photocurrent.

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Section: à2mentioning

confidence: 99%

Structure–property relationships of oligothiophene–isoindigo polymers for efficient bulk-heterojunction solar cells

Sun

Himmelberger

et al. 2014

Energy Environ. Sci.

Self Cite

110

118

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“…59,74,75 It has been hypothesized that such a morphology can not only facilitate exciton dissociation and but can also provide an easier route to percolation of the charge-carriers to their respective electrodes, 59 which can improve the J SC , without significantly affecting the V OC . 5,74 Moreover, due to the simplicity of the process compared to thermal or solvent annealing, 42,72 the incorporation of solvent additives is emerging as a popular route for improving the organic solar cell device performance.…”

Section: Tuning the Morphology: Effect Of Additivesmentioning

confidence: 99%

“…6.3%). 5 Amb et al reported BHJ devices based on dithienogermole-based polymers P-Si and P-Ge as donors and PC 71 BM as an acceptor. 17 TEM images of the devices revealed a dramatic difference in the extent of polymer-fullerene phase segregation and grain boundaries for devices processed with and without additives, with large PC 71 BM domains of dimensions 100-350 nm (lateral) and 45-65 nm (vertical) clearly seen for devices processed in the absence of additives (Fig.…”

Section: Tuning the Morphology: Effect Of Additivesmentioning

confidence: 99%

Incremental optimization in donor polymers for bulk heterojunction organic solar cells exhibiting high performance

Mayukh

Jung

et al. 2012

J Polym Sci B Polym Phys

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The power conversion efficiency of an organic solar cell has now exceeded the 10% mark, which is a significant improvement in the last decade. This has been made possible due to the development of low-band-gap polymers with tunable electron affinity, ionization potential, solubility, and miscibility with the fullerene acceptor, and the improved understanding of the factors affecting the critical device parameters such as the V OC and the J SC . This review examines the latest strategies, results, and trends that have evolved in the design of solar cells with better efficiency and durability.

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“…1). Extending these structures with dimers of thiophenes moves absorption into the infrared, but does not improve efficiency at first (Wang et al 2010b) but with improved processing comes to better than 6% (Wang et al 2011).…”

Section: Designer Polymersmentioning

confidence: 99%

Alternating Copolymers and Alternative Device Geometries for Organic Photovoltaics

Inganäs

Zhang

Andersson

2012

AMBIO

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The efficiency of conversion of light to electrical energy with the help of conjugated polymers and molecules is rapidly improving. The optical absorption properties of these materials can be designed, and implemented via molecular engineering. Full coverage of the solar spectrum is thus feasible. Narrow absorption spectra allow construction of tandem solar cells. The poor transport properties of these materials require thin devices, which limits optical absorption. Alternative device geometries for these flexible materials compensate for the optical absorption by light trapping, and allow tandem cells.

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An Easily Accessible Isoindigo-Based Polymer for High-Performance Polymer Solar Cells

Cited by 366 publications

References 42 publications

Structure–property relationships of oligothiophene–isoindigo polymers for efficient bulk-heterojunction solar cells

Structure–property relationships of oligothiophene–isoindigo polymers for efficient bulk-heterojunction solar cells

Incremental optimization in donor polymers for bulk heterojunction organic solar cells exhibiting high performance

Alternating Copolymers and Alternative Device Geometries for Organic Photovoltaics

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