Highly efficient organic photovoltaic devices utilizing work-function tuned graphene oxide derivatives as the anode and cathode charge extraction layers

Konios, Dimitrios; Kakavelakis, George; Petridis, C.; Savva, Kyriaki; Stratakis, Emmanuel; Kymakis, Emmanuel

doi:10.1039/c5ta09712f

Cited by 73 publications

(49 citation statements)

References 45 publications

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“…19 In this regard, 2D materials can be inserted as inter 20 or buffer layers 21 by modifying the chemical/physical properties of involved layers at the interface and eventually to improve the charge injection/collection at perovskite/CTLs interfaces. One of the main potentialities of 2D materials is the possibility to easily tailor their electronic structure, such as work function (WF) 22,23 or band gap, by proper functionalization 24 or by quantum confinement. 25 Fine-tuning of the WF allows to obtain appropriate energy level alignment leading to an ideal energy offset between perovskite active layer and CTLs, eventually inducing a built-in potential for efficient charge collection at the electrodes.…”

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confidence: 99%

Titanium-carbide MXenes for work function and interface engineering in perovskite solar cells

et al. 2019

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In order to improve the efficiency of perovskite solar cells (PSCs), careful device design and tailored interface engineering are needed to enhance optoelectronic properties and the charge extraction process at the selective electrodes. Here, we use two-dimensional transition metal carbides (the MXene Ti3C2TX) with various termination groups (TX) to tune the work function (WF) of the perovskite absorber and the TiO2 electron transport layer (ETL), and to engineer the perovskite/ETL interface. Ultraviolet photoemission spectroscopy measurements and Density Functional Theory calculations show that the addition of Ti3C2TX to halide perovskite and TiO2 layers permits to tune the materials' WFs, without affecting other electronic properties. Moreover, the dipole induced by the Ti3C2TX at the perovskite/ETL interface can be used to change the band alignment between these layers. The combined action of WF tuning and interface engineering can lead to substantial performance improvements in MXene-modified PSCs, as shown by the 26% increase of power conversion efficiency and hysteresis reduction with respect to reference cells without Mxene.

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confidence: 99%

Titanium-carbide MXenes for work function and interface engineering in perovskite solar cells

et al. 2019

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“…Specifically, PBDB‐T‐2F:Y6:PC 71 BM‐based cells yield a maximum PCE of 17.0%. This value is among the highest efficiencies reported to date for NFA‐based single junction solar cells and the highest for OPV cells comprising 2D materials as interfacial layers (Figure c) …”

Section: Summary Of Photovoltaic Operating Parameters For Pbdb‐t‐sf:imentioning

confidence: 67%

17% Efficient Organic Solar Cells Based on Liquid Exfoliated WS₂ as a Replacement for PEDOT:PSS

et al. 2019

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The application of liquid‐exfoliated 2D transition metal disulfides (TMDs) as the hole transport layers (HTLs) in nonfullerene‐based organic solar cells is reported. It is shown that solution processing of few‐layer WS2 or MoS2 suspensions directly onto transparent indium tin oxide (ITO) electrodes changes their work function without the need for any further treatment. HTLs comprising WS2 are found to exhibit higher uniformity on ITO than those of MoS2 and consistently yield solar cells with superior power conversion efficiency (PCE), improved fill factor (FF), enhanced short‐circuit current (JSC), and lower series resistance than devices based on poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) and MoS2. Cells based on the ternary bulk‐heterojunction PBDB‐T‐2F:Y6:PC71BM with WS2 as the HTL exhibit the highest PCE of 17%, with an FF of 78%, open‐circuit voltage of 0.84 V, and a JSC of 26 mA cm−2. Analysis of the cells' optical and carrier recombination characteristics indicates that the enhanced performance is most likely attributed to a combination of favorable photonic structure and reduced bimolecular recombination losses in WS2‐based cells. The achieved PCE is the highest reported to date for organic solar cells comprised of 2D charge transport interlayers and highlights the potential of TMDs as inexpensive HTLs for high‐efficiency organic photovoltaics.

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“…[132][133][134] The latter can then be deposited on different substrates by established printing/coating techniques So far, the durability of the graphene/TMDs-based photocathodes has been tested over no more than 1 hourperiod 80,84 and further investigations on these classes of 2D materials as CSLs for PEC application are needed. In fact, despite both graphene derivatives and TMD flakes have been demonstrated as efficient HSL and ESL in solution-processed PVs, including organic, [148][149][150][151][152][153][154] dye sensitized, 155,156 and perovskite solar cells, [157][158][159][160][161] no endurance tests have been reported for graphene/TDMs-based photocathodes.…”

Section: Introductionmentioning

confidence: 99%

Graphene-Based Hole-Selective Layers for High-Efficiency, Solution-Processed, Large-Area, Flexible, Hydrogen-Evolving Organic Photocathodes

et al. 2017

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Regio-regular poly(3-hexylthiophene-2,5-diyl) (rr-P3HT), the work-horse of organic photovoltaics, has been recently exploited in bulk heterojunction (BHJ) configuration with phenyl-C61-butyric acid methyl ester (PCBM) for solution-processed hydrogen-evolving photocathodes, reaching cathodic photocurrents at 0 V vs. RHE (J 0V vs RHE ) of up to 8 mA cm -2 . The photoelectrochemical performance of these photocathodes strongly depends on the presence of the electron (ESL) and hole (HSL) selective layer. While TiO 2 and its sub-stoichiometric phases are consolidated ESL materials, the currently used HSLs (e.g., MoO 3 , CuI, PEDOTT:PSS, WO 3 ) suffer electrochemical degradation under hydrogen evolution reaction (HER)-working conditions. In this work, we use solution-processed graphene derivatives as HSL to boost efficiency and durability of rr-P3HT:PCBM-based photocathodes, demonstrating record-high performance. In fact, our devices show cathodic J 0V vs RHE of 6.01 mA cm -2 , onset potential (V o ) of 0.6 V vs. RHE, ratiometric power-saved efficiency (φ saved ) of 1.11% and operational activity of 20 hours in 0.5 M H 2 SO 4 solution. Moreover, the designed photocathodes are effectively working in different pH environments ranging from acid to basic. This is pivotal for their exploitation in tandem configurations, where photoanodes operate only in restricted electrochemical conditions. Furthermore, we demonstrate the scalability of our all-solution processed approach by fabricating a large-area (~9 cm 2 ) photocathode on flexible substrate, achieving remarkable cathodic J 0V vs RHE of 2.8 mA cm -2 , V o of 0.45 V vs. RHE and φ saved of 0.31%. This is the first demonstration of highefficient rr-P3HT:PCBM flexible photocathodes based on low-cost and solution-processed manufacturing techniques.

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Highly efficient organic photovoltaic devices utilizing work-function tuned graphene oxide derivatives as the anode and cathode charge extraction layers

Abstract: Utilization of work-function (WF) tuned graphene oxide derivatives as cathode and anode buffer layers in organic photovoltaics (OPVs) is demonstrated.

Cited by 73 publications

References 45 publications

Titanium-carbide MXenes for work function and interface engineering in perovskite solar cells

Titanium-carbide MXenes for work function and interface engineering in perovskite solar cells

17% Efficient Organic Solar Cells Based on Liquid Exfoliated WS₂ as a Replacement for PEDOT:PSS

Graphene-Based Hole-Selective Layers for High-Efficiency, Solution-Processed, Large-Area, Flexible, Hydrogen-Evolving Organic Photocathodes

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Highly efficient organic photovoltaic devices utilizing work-function tuned graphene oxide derivatives as the anode and cathode charge extraction layers

Abstract: Utilization of work-function (WF) tuned graphene oxide derivatives as cathode and anode buffer layers in organic photovoltaics (OPVs) is demonstrated.

Cited by 73 publications

References 45 publications

Titanium-carbide MXenes for work function and interface engineering in perovskite solar cells

Titanium-carbide MXenes for work function and interface engineering in perovskite solar cells

17% Efficient Organic Solar Cells Based on Liquid Exfoliated WS2 as a Replacement for PEDOT:PSS

Graphene-Based Hole-Selective Layers for High-Efficiency, Solution-Processed, Large-Area, Flexible, Hydrogen-Evolving Organic Photocathodes

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17% Efficient Organic Solar Cells Based on Liquid Exfoliated WS₂ as a Replacement for PEDOT:PSS