Indacenodithiophene-based wide bandgap copolymers for high performance single-junction and tandem polymer solar cells

Ma, Yunlong; Chen, Shan‐Ci; Wang, Zaiyu; Ma, Wei; Wang, Jin-Yun; Yin, Zhigang; Tang, Changquan; Cai, Dongdong; Zheng, Qingdong

doi:10.1016/j.nanoen.2017.01.050

Cited by 54 publications

(34 citation statements)

References 65 publications

(6 reference statements)

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“…When blended with PC 70 BM, an efficiency of 11.3% was reported for a homo‐tandem device with this active layer despite the lack of complementarity in the absorption due to the use of the same absorber for both the front and back subcells . More groups reported similar efficiencies for tandem cells featuring this blend in one of the two subcells . Zheng et al combined the polythiophene PDCBT and the benzodithiophene‐based PBDT‐TS1, blended with PC 70 BM and PC 60 BM, respectively in a tandem device .…”

Section: Tandem Solar Cellsmentioning

confidence: 99%

Advances in Solution‐Processed Multijunction Organic Solar Cells

2018

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Single-junction solar cells are principally limited in performance by two factors (Figure 1a). Electrons excited by photons with energy higher than the bandgap relax to the band edges, releasing surplus energy as heat (thermalization loss). Photons with energy lower than the bandgap are not absorbed (transmission loss). These losses can be alleviated with two or more absorber layers. The first layer should feature a wide bandgap material to reduce the thermalization loss for high-energy photons. The second layer should have a lower bandgap to absorb the low-energy photons that pass the first layer. In such configuration a tandem cell provides less thermalization and less transmission losses than each of the corresponding single-junction cells. In the detailed-balance limit, a double-junction (tandem) cell can reach an efficiency of 42% and a triple-junction cell 49%. [6] To construct a tandem cell, the two complementary absorber layers must be stacked optically and electrically ( Figure 1b). The interconnecting layer (ICL) between the two subcells must pass light and sustain the photocurrent by providing an optically transparent electrical contact for recombination of electrons and holes from the adjacent photoactive layers. The Fermi level of the hole-transporting layer (HTL) and the electron-transporting layer (ETL) that jointly form the ICL must match the relevant highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels in the adjacent photoactive layers (Figure 1b). The ICL should not cause voltage losses and have low resistance. The open-circuit voltage (V OC ) of the tandem solar cell is ideally the sum of the V OC s of the subcells and the photocurrent is limited by the subcell generating less current. To overcome the intrinsic performance limits of single-junction cells, the subcells should absorb complementary regions of the solar spectrum and generate equal photocurrent.In the first organic tandem solar cells, materials were thermally evaporated. Initially only metal clusters were used to interconnect the subcells, [7][8][9] later complemented by p-and n-doped organic transport layers. [10,11] In 2007, the first fully solution-processed tandem polymer solar cells were reported by Gilot et al. [12] and Kim et al. [13] In both examples the ICL featured a layer of poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) as HTL, stacked on top of either a zinc oxide or a titanium oxide layer as ETL. Kim et al. achieved a PCE of 6.5%. Since then PCEs have steadily increased. Major improvements involved the use of more efficient photoactive blends that afford a high V OC relative to their optical bandgap The efficiency of organic solar cells can benefit from multijunction device architectures, in which energy losses are substantially reduced. Herein, recent developments in the field of solution-processed multijunction organic solar cells are described. Recently, various strategies have been investigated and implemented to improve the performance of these device...

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Section: Tandem Solar Cellsmentioning

confidence: 99%

Advances in Solution‐Processed Multijunction Organic Solar Cells

2018

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“…Che et al used thermally evaporated bathophenanthroline:C 60 (1:1) with an ultrathin Ag nanoparticle layer that allowed processing of acidic PEDOT:PSS on top. Other ICLs involving thermal evaporation are ZnO/Al/MoO 3 or a hybrid electron transport layer in combination with Al/MoO 3 . Ideally, a fully solution‐processable ETL with enough chemical stability to withstand the processing of acidic PEDOT:PSS would exist.…”

Section: Introductionmentioning

confidence: 99%

Solution‐Processed Tin Oxide‐PEDOT:PSS Interconnecting Layers for Efficient Inverted and Conventional Tandem Polymer Solar Cells

et al. 2019

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Tin oxide nanoparticles are employed as an electron transporting layer in solution‐processed polymer solar cells. Tin oxide based devices yield excellent performance and can interchangeably be used in conventional and inverted device configurations. In combination with poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) as a hole transporting layer, tin oxide forms an effective interconnecting layer (ICL) for tandem solar cells. Conventional and inverted tandem cells with this ICL provide efficiencies up to 10.4% in good agreement with optical‐electrical modeling simulations. The critical advantage of tin oxide in an ICL in a conventional tandem structure over the commonly used zinc oxide is that the latter requires the use of a pH‐neutral formulation of PEDOT:PSS to fabricate the ICL, limiting the open‐circuit voltage (VOC) because of its low work function. The SnO2/PEDOT:PSS ICL, on the other hand, provides a nearly loss‐free VOC.

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“…In recent years, several different combinations of materials have been proposed as ICL, involving either organic materials or transparent semiconducting metal oxides . For the selective extraction of holes from the photoactive layers poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) is widely used but also metal oxides such as MoO 3 , V 2 O 5 , and WO 3 , or graphene oxide (GO) can be used for the purpose.…”

Section: Introductionmentioning

confidence: 99%

A Universal Route to Fabricate n‐i‐p Multi‐Junction Polymer Solar Cells via Solution Processing

et al. 2018

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The interconnection layer (ICL) that connects adjacent subcells electrically and optically in solution‐processed multi‐junction polymer solar cells must meet functional requirements in terms of work functions, conductivity, and transparency, but also be compatible with the multiple layer stack in terms of processing and deposition conditions. Using a combination of poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate, diluted in near azeotropic water/n‐propanol dispersions as hole transport layer, and ZnO nanoparticles, dispersed in isoamyl alcohol as electron transport layer, a novel, versatile ICL has been developed for solution‐processed tandem and triple‐junction solar cells in an n‐i‐p architecture. The ICL has been incorporated in six different tandem cells and three different triple‐junction solar cells, employing a range of different polymer‐fullerene photoactive layers. The new ICL provided an essentially lossless contact in each case, without the need of adjusting the formulations or deposition conditions. The approach permitted realizing complex devices in good yields, providing a power conversion efficiency up to 10%.

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Indacenodithiophene-based wide bandgap copolymers for high performance single-junction and tandem polymer solar cells

Cited by 54 publications

References 65 publications

Advances in Solution‐Processed Multijunction Organic Solar Cells

Advances in Solution‐Processed Multijunction Organic Solar Cells

Solution‐Processed Tin Oxide‐PEDOT:PSS Interconnecting Layers for Efficient Inverted and Conventional Tandem Polymer Solar Cells

A Universal Route to Fabricate n‐i‐p Multi‐Junction Polymer Solar Cells via Solution Processing

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