High‐Efficiency Polymer Homo‐Tandem Solar Cells with Carbon Quantum‐Dot‐Doped Tunnel Junction Intermediate Layer

Kang, Rakwon; Park, Sujung; Jung, Yun Kyung; Lim, Dong Chan; Joo, Myung; Seo, Jung Hwa; Cho, Shinuk

doi:10.1002/aenm.201702165

Cited by 37 publications

(19 citation statements)

References 44 publications

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“…Raïssi et al showed an ICL consisting of PEDOT:PSS, on top of which they deposited an ETL made from a mixture of single‐walled carbon nanotubes (SWNT) and a phthalocyanine derivative (TSCuPc), and the sole phthalocyanine . Another form of carbon for the ICL is carbon quantum dots (CQDs), mixed with PEI as described by Kang et al CQDs were synthesized by a microwave reaction starting from citric acid and β‐alanine, resulting in particles with a size of ≈3 nm. A thin layer of the CQDs/PEIE composite on top of PEDOT:PSS was reported to provide an efficient tunneling junction for the recombination of charges in the ICL, affording a best efficiency of 12.1%.…”

Section: Tandem Solar Cellsmentioning

confidence: 99%

“…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%

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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%

Section: Tandem Solar Cellsmentioning

confidence: 99%

Advances in Solution‐Processed Multijunction Organic Solar Cells

2018

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“…[32] www.advmat.de www.advancedsciencenews.com Adv. The LED (λ = 635 nm) provided both the DC and AC components of the illumination, where the modulation depth of the AC component superimposed on the DC light was 10%.…”

Section: Methodsmentioning

confidence: 99%

Highly Efficient and Stable Inverted Perovskite Solar Cell Obtained via Treatment by Semiconducting Chemical Additive

et al. 2018

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Solar energy is widely regarded as a highly efficient and sustainable source for future energy harvesting. In particular, organicinorganic hybrid perovskite solar cells (PeSCs), which exhibit remarkable power conversion efficiencies (PCEs) exceeding 22% [1] and unique optoelectronic properties, [1c,2] have attracted considerable interest as the most promising materials for large-scale solar energy conversion. [3] In general, the morphology and crystallinity of organic-inorganic halide perovskite films are considered to be crucial to both the efficiency and the stability of PeSCs. [4] Large-sized, highly crystallized, and preferentially oriented perovskite grains provide good surface coverage and a small grain boundary area, which effectively minimize not only the presence of pinholes but also the trapping and recombination of charge carriers. [5] In this respect, considerable effort has been devoted toward preparing high-quality perovskite films with large-sized grains for significantly improving the device performance of PeSCs. [6] Among the various approaches for increasing the perovskite grain size, the addition of chemical additives, such as hypophosphorous acid, [7] methylammonium chloride, [8] 1,8-diiodooctane, [9] urea, [10] and lead thiocyanate (Pb(SCN) 2 ), [11] is widely adopted as it can exploit simple low-temperature processes (typically <150 °C) desirable for effective continuous processing. [12] Although such additive engineering remarkably increases the perovskite grain size to the micrometer scale under extremely mild conditions, the inherent insulating property of the additives prevents the efficient extraction and transport of charge carriers in the perovskite layers, [13] thereby limiting the applicability of this approach.In this paper, we report a semiconducting organic conjugated molecule (SA-1) as a novel chemical additive that increases the grain size of perovskite films without hindering the charge transport and thus improves the device performance considerably (Figure 1a-c). Experimental and analytical investigations revealed that the addition of SA-1 remarkably increased the perovskite grain size through a Lewis acid-base interaction and facilitated charge transport and extraction in the perovskite layer owing to suitable energy level matching and high charge The addition of chemical additives is considered as a promising approach for obtaining high-quality perovskite films under mild conditions, which is essential for both the efficiency and the stability of organic-inorganic hybrid perovskite solar cells (PeSCs). Although such additive engineering yields high-quality films, the inherent insulating property of the chemical additives prevents the efficient transport and extraction of charge carriers, thereby limiting the applicability of this approach. Here, it is shown that organic conjugated molecules having rhodanine moieties (i.e., SA-1 and SA-2) can be used as semiconducting chemical additives that simultaneously yield large-sized perovskite grains and improve the charge extr...

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“…[25] To get rid of this obstacle, an interlayer between the electrodes and organic layers is applied to facilitate the transfer of charges in organic devices. [31,32] Among different interlayer materials used so far, zwitterionic materials have been proved Zwitterions, a class of materials that contain covalently bonded cations and anions, have been extensively studied in the past decades owing to their special features, such as excellent solubility in polar solvents, for solution processing and dipole formation for the transfer of carriers and ions. While in the case of OSCs and PVSCs, apart from the enhancement in charge injection, they also play an important role to increase the built-in electric field across the active layer, ensuring efficient extraction of photogenerated charge carriers.…”

Section: Doi: 101002/aenm201803354mentioning

confidence: 99%

mentioning

confidence: 99%

Zwitterions for Organic/Perovskite Solar Cells, Light‐Emitting Devices, and Lithium Ion Batteries: Recent Progress and Perspectives

Islam

Pervaiz

et al. 2019

Advanced Energy Materials

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are covalently bonded and their unique characteristics enable them to demonstrate special performance in applications and distinguish them from other conventional organic salts. [12][13][14] Recently, a significant attention has been paid to the use of zwitterions owing to their solubility in polar solvents for solution processing, [15][16][17] and dipole formation for the transfer of carriers [18][19][20] and ions. [21][22][23] Zwitterions have emerged as alternatives to the widely used building blocks such as conventional ionic groups, for developing new functional materials. The presence of both negative and positive ions in the same molecule enables zwitterions to develop interfacial dipole. The ability of zwitterions to develop interfacial dipole provides a new pathway to utilize them as interfacial layer in optoelectronic devices, including organic solar cells (OSCs), perovskite solar cells (PVSCs), and organic light-emitting devices (OLEDs), as well as electrolyte additives for energy devices such as lithium ion batteries (LIBs).It is well known that the ability to transport the charge carriers between the electrodes and organic layers is very crucial to obtain highly efficient electronic devices. [24] A mismatch between the energy levels of organic layers and inorganic electrodes leads to the generation of an energy barrier that hampers the extraction or injection of charge carriers. [25] To get rid of this obstacle, an interlayer between the electrodes and organic layers is applied to facilitate the transfer of charges in organic devices. In OLEDs, interlayers are used to enhance charge injection and reduce the height of Schottky barrier. While in the case of OSCs and PVSCs, apart from the enhancement in charge injection, they also play an important role to increase the built-in electric field across the active layer, ensuring efficient extraction of photogenerated charge carriers. [26][27][28][29][30] Therefore, the design and development of effective interlayer materials for interfacial modification are crucial for high-performance electronic devices. Recently, some significant advances have been demonstrated by applying an interfacial layer between the electrodes and organic layers, resulting in power conversion efficiencies (PCEs) to exceed 14% for single-junction OSCs by choosing appropriate photoactive layer. [31,32] Among different interlayer materials used so far, zwitterionic materials have been proved Zwitterions, a class of materials that contain covalently bonded cations and anions, have been extensively studied in the past decades owing to their special features, such as excellent solubility in polar solvents, for solution processing and dipole formation for the transfer of carriers and ions. Recently, zwitterions have been developed as electrode modifiers for organic solar cells (OSCs), perovskite solar cells (PVSCs), and organic light-emitting devices (OLEDs), as well as electrolyte additives for lithium ion batteries (LIBs).With the rapid advances of zwitterionic materials, high-performan...

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High‐Efficiency Polymer Homo‐Tandem Solar Cells with Carbon Quantum‐Dot‐Doped Tunnel Junction Intermediate Layer

Cited by 37 publications

References 44 publications

Advances in Solution‐Processed Multijunction Organic Solar Cells

Advances in Solution‐Processed Multijunction Organic Solar Cells

Highly Efficient and Stable Inverted Perovskite Solar Cell Obtained via Treatment by Semiconducting Chemical Additive

Zwitterions for Organic/Perovskite Solar Cells, Light‐Emitting Devices, and Lithium Ion Batteries: Recent Progress and Perspectives

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