Light Extraction of Trapped Optical Modes in Polymer Light-Emitting Diodes with Nanoimprinted Double-Pattern Gratings

Zhou, Lei; Jiang, Xiaochen; Li, Yanqing; Shi, Ai-Li; Chen, Jingde; Ou, Qingdong; Liu, Haitao; Tang, Jianxin

doi:10.1021/am5050357

Cited by 41 publications

(24 citation statements)

References 49 publications

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“…Obviously, patterning the PCBM ETL and Ag back electrode can remarkably affect the near-field distributions of incident light inside PeSCs, where the field distributions in perovskite absorbers are increased. According to the previous reports on solar cells with nanostructured absorber or electrodes, [20,29,[42][43][44] the EQE enhancement peak at around 480 nm (Figure 3b) can be attributed to the excitation of waveguide mode, which corresponds to the standing waves induced by constructive interference between traveling waves in the grating structure with a period of 500 nm used in this work. According to the previous reports on solar cells with nanostructured absorber or electrodes, [20,29,[42][43][44] the EQE enhancement peak at around 480 nm (Figure 3b) can be attributed to the excitation of waveguide mode, which corresponds to the standing waves induced by constructive interference between traveling waves in the grating structure with a period of 500 nm used in this work.…”

supporting

confidence: 66%

Enhanced Light Harvesting in Perovskite Solar Cells by a Bioinspired Nanostructured Back Electrode

Wei

et al. 2017

Advanced Energy Materials

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perovskite materials. [1][2][3][4][5][6][7] Since 2009, rapid progress has been made on the performance of methylammonium lead halide perovskite (CH 3 NH 3 PbX 3 , X = Cl, Br, I)based PeSCs with a substantial increase in power conversion efficiency (PCE) from 3.8% to a stunning value of more than 22%. [8][9][10] Typically, a PeSC is composed of a perovskite absorber layer sandwiched between the hole and the electron transport layers (HTLs and ETLs, respectively). [11] Upon the absorption of incident light, carriers will generate in the perovskite absorber and transport to HTL or ETL, and finally are collected by the corresponding electrodes. To achieve highly efficient and low-cost PeSCs, great efforts have been devoted to optimizing the perovskite material design, device structures and relevant processing techniques. [1][2][3][4][5][6][7][8][9][12][13][14][15] Apart from the major emphasis on perovskite film processing and interface modification for efficient charge collection, it is still of great challenges to achieve maximum light trapping within the devices and then make the majority of incident light for photoelectric conversion. For instance, the photocurrent density of the reported PeSCs were still lower than the theoretical one of ≈26 mA cm −2 , [16] indicating that quite a large fraction of incident light still remains unused for photocurrent generation. The increased physical thickness of the perovskite absorber allows for better light absorption, which however certainly reduces the charge collection efficiency due to the increased recombination current. To alleviate this contradiction, light-trapping schemes are imperative for effectively enhancing light harvesting efficiencies in PeSCs by increasing the internal scattering and absorption of incident light with lower recombination currents.To date, numerous light manipulation strategies using periodic or random structures have been proposed such as plasmonic structures, [17] microlens array, [18] metal nanoparticles, [19] aperiodic arrays, [20][21][22] microresonators, [23] and optical cavities. [24,25] By introducing these schemes to the appropriate interfaces in thin-film solar cells, light absorption can be effectively enhanced by guiding and retaining the incident light through the enhancement of optical path length or the spatial redistribution of light intensity due to surface plasmon resonances (SPRs). Nevertheless, most of these schemes are limited for the practical adoption in large-area solar cell fabrication Light management holds great promise of realizing high-performance perovskite solar cells by improving the sunlight absorption with lower recombination current and thus higher power conversion efficiency (PCE). Here, a convenient and scalable light trapping scheme is demonstrated by incorporating bioinspired moth-eye nanostructures into the metal back electrode via soft imprinting technique to enhance the light harvesting in organic-inorganic lead halide perovskite solar cells. Comparedto the flat reference cell with a methylammonium le...

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confidence: 66%

Enhanced Light Harvesting in Perovskite Solar Cells by a Bioinspired Nanostructured Back Electrode

Wei

et al. 2017

Advanced Energy Materials

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“…A second embossing on a UV-curable resist, which was spun-cast on the OLED bottom surface, allowed out-coupling enhancement by a factor 2 and improvement of external quantum efficiency by $130 %. The same group reported the incorporation of Bragg gratings in both hole transporting (PEDOT:PSS) and emitting (poly(p-phenylene vinylene), MEH-PPV) layers by NIL, achieving 35 % current efficiency enhancement with respect to the flat devices [157]. These results prove that, in addition to high throughput and low costs, NIL can greatly simplify the fabrication process to yield high efficient structure.…”

Section: Organic Light Emitting Diodesmentioning

confidence: 83%

Nanoimprint Lithography: Toward Functional Photonic Crystals

Lova

Soci

2015

Organic and Hybrid Photonic Crystals

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In this chapter we review the use of nanoimprint lithography and its derivative soft-lithography techniques for the fabrication of functional photonic crystals. Nanoimprint is a viable, scalable, and cost-effective solution for large area patterning. While initially it relied primarily on pattern transfer from a rigid mold to a thermally softened polymer by embossing, in the last two decades the process evolved rapidly, giving rise to new technologies that allow direct imprint of functional materials such as conjugated polymers, metals, biological matter, and metal oxides. These advancements generated increasing interest in the use of nanoimprint lithography for the fabrication of photonic structures for light management in optoelectronic devices. After describing standard nanoimprint lithography and its derivative soft-lithography methods, we briefly discuss nanoimprint capabilities and prospects in photonic applications. In particular we review recent implementations of imprinted photonic structures for light management in organic light emitting diodes, solar cells, solid state lasers and sensors.

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“…By treating the film in argon atmosphere afterwards, we could reach sheet resistances as low as for commercial ITO covered substrates (20 Ω/sq). In optical studies, the film shows decreased direct but increased absolute transmission, indicating its anti‐reflection properties and its excellent suitability for optoelectronic devices, in particular as anode material for organic light emitting diodes, as the positive impact of surface patterned out‐coupling layers on the EQE of such devices is evident …”

Section: Resultsmentioning

confidence: 99%

“…In optical studies, the film shows decreased direct but increased absolute transmission, indicating its anti-reflection properties and its excellent suitability for optoelectronic devices, in particular as anode material for organic light emitting diodes, as the positive impact of surface patterned out-coupling layers on the EQE of such devices is evident. [36][37][38] Concluding we consider the material to represent a perfect candidate for combining the properties of a good anode material as well as its dispersive behavior to enhance light outor in-coupling for several applications.…”

Section: Resultsmentioning

confidence: 99%

Conductive ITO Interfaces for Optoelectronic Applications Based on Highly Ordered Inverse Opal Thin Films

et al. 2020

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A three‐step fabrication process for optically transparent, conducting ITO thin films with an intrinsic inverse opal structure is described. The preparation is based on colloidal crystal templating using polystyrene microspheres (100 nm–600 nm). For the realization of varying periodicities in this structure, different sphere sizes were assembled to monolayers on a substrate by spin coating and infiltrated afterwards similarly. The influence of rotation parameters as well as dispersion concentration was studied. Using this approach different geometries of the surface are accessible by systematically varying the rotation parameters and infiltration volume. The thin films show excellent anti‐reflection behavior, good transmission (>80% in the visible range) as well as a low resistance of 200 Ω/sq compared to other porous ITO interfaces. The properties are very promising for several optoelectronic applications such as in‐ or out‐coupling structures in solar cells and organic light emitting diodes.

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Light Extraction of Trapped Optical Modes in Polymer Light-Emitting Diodes with Nanoimprinted Double-Pattern Gratings

Cited by 41 publications

References 49 publications

Enhanced Light Harvesting in Perovskite Solar Cells by a Bioinspired Nanostructured Back Electrode

Enhanced Light Harvesting in Perovskite Solar Cells by a Bioinspired Nanostructured Back Electrode

Nanoimprint Lithography: Toward Functional Photonic Crystals

Conductive ITO Interfaces for Optoelectronic Applications Based on Highly Ordered Inverse Opal Thin Films

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