The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform

Frederik C Krebs - One of the best experts on this subject based on the ideXlab platform.

  • Scalability and stability of very thin, roll-to-roll processed, large area, indium-tin-oxide free Polymer Solar Cell modules
    Organic Electronics: physics materials applications, 2013
    Co-Authors: Dechan Angmo, Thue T. Larsen-olsen, Markus Hösel, Suren A Gevorgyan, Roar R Sondergaard, Giridhar U. Kulkarni, Ritu Gupta, Mikkel Jorgensen, Frederik C Krebs
    Abstract:

    Polymer Solar Cell modules were prepared directly on thin flexible barrier polyethylene terephthalate foil. The performance of the modules was found to be scalable from a single Cell with an area of 6 cm2to modules with a total area of up to 186 cm2. The substrate thickness was also explored and the performance was found to be independent of thickness in the range of 20-130 μm. The thinner substrates were found to present some challenge regarding handling but were not limited in performance. Large area modules on a substrate thickness of 45 μm were finally prepared by full roll-to-roll processing employing P3HT:PCBM as the active material and were found to exhibit a total area efficiency of >1% (1000 W/m-2; AM1.5G) with a typical active-area efficiency in the 1.5-1.6% for total module area of >110 cm2due to high fill factors in excess of 50%. The modules were also found to have an active-area efficiency of >1% under low light levels (∼100 W m-2). The modules were then subjected to extensive stability testing for a minimum of 1000 h employing several ISOS protocols. The modules presented higher than 80% of the initial performance (T80) in the dark (ISOS-D-1), in dark under elevated temperature of 65°C (ISOS-D-2), under low light (ISOS-LL), under full sunlight (ISOS-L-2), and under outdoor testing (ISOS-O), which was conducted in two locations in India and Denmark. We estimate maximum T80 for those tests to be 2800, 5000, 1300, 1000, and 3500 h respectively. The modules showed significant sensitivity to high humidity and had low values for T80 for dark storage tests at 50°C/85%RH (ISOS-D-3) and accelerated operation conditions with 0.7 sun/65 oC/50%RH (ISOS-L-3). We found the modules to be particularly suited for information and communications technology (ICT) and mobile applications where low humidity (

  • a laboratory scale approach to Polymer Solar Cells using one coating printing machine flexible substrates no ito no vacuum and no spincoating
    Solar Energy Materials and Solar Cells, 2013
    Co-Authors: Jon Eggert Carle, Mikkel Jorgensen, Martin Helgesen, Thomas Rieks Andersen, Eva Bundgaard, Frederik C Krebs
    Abstract:

    Abstract Printing of the silver back electrode under ambient conditions using simple laboratory equipment has been the missing link to fully replace evaporated metal electrodes. Here we demonstrate how a recently developed roll coater is further developed into a single machine that enables processing of all layers of the Polymer Solar Cell without moving the substrate from one machine to another. The novel approach to Polymer Solar Cells is readily scalable using one compact laboratory scale coating/printing machine that is directly compatible with industrial and pilot scale roll-to-roll processing. The use of the techniques was successfully demonstrated in one continuous roll process on flexible polyethyleneterphthalate (PET) substrates and Polymer Solar Cells were prepared by solution processing of five layers using only slot-die coating and flexographic printing. The devices obtained did not employ indium–tin-oxide (ITO) or vacuum evaporation steps making it a significant step beyond the traditional laboratory Polymer Solar Cell processing methods involving spin coating and metal evaporation.

  • edge sealing for low cost stability enhancement of roll to roll processed flexible Polymer Solar Cell modules
    Solar Energy Materials and Solar Cells, 2012
    Co-Authors: David M Tanenbaum, Mikkel Jorgensen, Henrik Friis Dam, Roland Rosch, Harald Hoppe, Frederik C Krebs
    Abstract:

    Abstract Fully roll-to-roll processed Polymer Solar Cell modules were prepared, characterized, and laminated. Cell modules were cut from the roll and matched pairs were selected, one module with exposed cut edges, the other laminated again with the same materials and adhesive sealing fully around the cut edges. The edge sealing rim was 10 mm wide. Cell modules were characterized by periodic measurements of IV curves over extended periods in a variety of conditions, as well as by a variety of spatial imaging techniques. Data show significant stability benefits of the edge sealing process. The results of the imaging experiments show that the ingress of atmospheric reactants from the edges leads to degradation. In the case of edge sealed devices the same effects are observed but significantly slowed down. In particular, the fast nonlinear degradation is eliminated.

  • a life cycle analysis of Polymer Solar Cell modules prepared using roll to roll methods under ambient conditions
    Solar Energy Materials and Solar Cells, 2011
    Co-Authors: Nieves Espinosa, Rafael Garciavalverde, Antonio Urbina, Frederik C Krebs
    Abstract:

    A life cycle analysis was performed on a full roll-to-roll coating procedure used for the manufacture of flexible Polymer Solar Cell modules. The process known as ProcessOne employs a polyester substrate with a sputtered layer of the transparent conductor indium-tin-oxide (ITO). The ITO film was processed into the required pattern using a full roll-to-roll process, employing screen printing of an etch resist and then applying etching, stripping, washing and drying procedures. The three subsequent layers; ZnO, P3HT:PCBM and PEDOT:PSS were slot-die coated and the silver back electrode was screen printed. Finally the Polymer Solar modules were encapsulated, using a polyester barrier material. All operations except the application of ITO were carried out under ambient conditions. The life cycle analysis delivered a material inventory of the full process for a module production, and an accountability of the energy embedded both in the input materials and in the production processes. Finally, upon assumption of power conversion efficiencies and lifetime for the modules, a calculation of energy pay-back time allowed us to compare this roll-to-roll manufacturing with other organic and hybrid photovoltaic technologies. The results showed that an Energy Pay-Back Time (EPBT) of 2.02 years can be achieved for an organic Solar module of 2% efficiency, which could be reduced to 1.35 years, if the efficiency was 3%.

  • life cycle analysis of product integrated Polymer Solar Cells
    Energy and Environmental Science, 2011
    Co-Authors: Nieves Espinosa, Rafael Garciavalverde, Frederik C Krebs
    Abstract:

    A life cycle analysis (LCA) on a product integrated Polymer Solar module is carried out in this study. These assessments are well-known to be useful in developmental stages of a product in order to identify the bottlenecks for the up-scaling in its production phase for several aspects spanning from economics through design to functionality. An LCA study was performed to quantify the energy use and greenhouse gas (GHG) emissions from electricity use in the manufacture of a light-weight lamp based on a plastic foil, a lithium-Polymer battery, a Polymer Solar Cell, printed circuitry, blocking diode, switch and a white light emitting semiconductor diode. The Polymer Solar Cell employed in this prototype presents a power conversion efficiency in the range of 2 to 3% yielding energy payback times (EPBT) in the range of 1.3–2 years. Based on this it is worthwhile to undertake a life-cycle study on the complete product integrated Polymer Solar Cell. We have compared this portable lighting system with other lighting solutions, namely: a kerosene lamp in a remote rural area in Africa (Ethiopia), as a replacement of a silicon PV based lamp, in place of a torch with non-rechargeable lead-acid battery and instead of a battery charging station. The analysis reveals that the OPV lamp has a significant advantage provided that some of the challenges facing this novel technology are efficiently met such that it can enter the market of portable lighting devices.

Jianhui Hou - One of the best experts on this subject based on the ideXlab platform.

  • highly efficient fullerene free Polymer Solar Cells fabricated with polythiophene derivative
    Advanced Materials, 2016
    Co-Authors: Yu Chen, Yunpeng Qin, Mohammad Afsar Uddin, Bomee Jang, Kang Zhao, Zhong Zheng, Tae Joo Shin, Han Young Woo, Jianhui Hou
    Abstract:

    A highly efficient fullerene-free Polymer Solar Cell (PSC) based on PDCBT, a polythiophene derivative substituted with alkoxycarbonyl, achieves an impressive power conversion efficiency of 10.16%, which is the best result in PSCs based on polythiophene derivatives to date. In comparison with a poly(3-hexylthiophene):ITIC-based device, the photovoltaic and morphological properties of the PDCBT:ITIC-based device are carefully investigated and interpreted.

  • fullerene free Polymer Solar Cells with over 11 efficiency and exCellent thermal stability
    Advanced Materials, 2016
    Co-Authors: Wenchao Zhao, Olle Inganäs, Shaoqing Zhang, Deping Qian, Sunsun Li, Feng Gao, Jianhui Hou
    Abstract:

    A nonfullerene-based Polymer Solar Cell (PSC) that significantly outperforms fullerene-based PSCs with respect to the power-conversion efficiency is demonstrated for the first time. An efficiency o ...

  • fullerene free Polymer Solar Cells with over 11 efficiency and exCellent thermal stability
    Advanced Materials, 2016
    Co-Authors: Wenchao Zhao, Olle Inganäs, Shaoqing Zhang, Deping Qian, Feng Gao, Jianhui Hou
    Abstract:

    A nonfullerene-based Polymer Solar Cell (PSC) that significantly outperforms fullerene-based PSCs with respect to the power-conversion efficiency is demonstrated for the first time. An efficiency of >11%, which is among the top values in the PSC field, and exCellent thermal stability is obtained using PBDB-T and ITIC as donor and acceptor, respectively.

  • Enhanced Efficiency in Fullerene-Free Polymer Solar Cell by Incorporating Fine-designed Donor and Acceptor Materials
    ACS applied materials & interfaces, 2015
    Co-Authors: Kai Sun, Shaoqing Zhang, Wei Jiang, Wenchao Zhao, Huifeng Yao, Zhaohui Wang, Jianhui Hou
    Abstract:

    Among the diverse nonfullerene acceptors, perylene bisimides (PBIs) have been attracting much attention due to their exCellent electron mobility and tunable molecular and electronic properties by simply engineering the bay and head linkages. Herein, guided by two efficient small molecular acceptors, we designed, synthesized, and characterized a new nonfullerene small molecule PPDI with fine-tailored alkyl chains. Notably, a certificated PCE of 5.40% is realized in a simple structured fullerene-free Polymer Solar Cell comprising PPDI as the electron acceptor and a fine-tailored 2D-conjugated Polymer PBDT-TS1 as the electron donor. Moreover, the device behavior, morphological feature, and origin of high efficiency in PBDT-TS1/PPDI-based fullerene-free PSC were investigated. The synchronous selection and design of donor and acceptor materials reported here offer a feasible strategy for realizing highly efficient fullerene-free organic photovoltaics.

  • realizing over 10 efficiency in Polymer Solar Cell by device optimization
    Science China-chemistry, 2015
    Co-Authors: Shaoqing Zhang, Jianhui Hou, Wenchao Zhao, Bei Yang, Qi Wang
    Abstract:

    The low band gap Polymer based on benzodithiophene (BDT)-thieno[3,4-b]thiophene (TT) backbone, PBDT-TS1, was synthesized following our previous work and the bulk heterojunction (BHJ) material comprising PBDT-TS1/PC71BM was optimized and characterized. By processing the active layer with different additives i.e. 1,8-diiodooctane (DIO), 1-chloronaphthalene (CN) and 1, 8-octanedithiol (ODT) and optimizing the ratio of each additive in the host solvent, a high PCE of 9.98% was obtained under the condition of utilizing 3% DIO as processing additive in CB. The effect of varied additives on photovoltaic performance was illustrated with atomic force microscopy (AFM) and transmission electron microscope (TEM) measurements that explained changes in photovoltaic parameters. These results provide valuable information of solvent additive choice in device optimization of PBDTTT Polymers, and the systematic device optimization could be applied in other efficient photovoltaic Polymers. Apparently, this work presents a great advance in single junction PSCs, especially in PSCs with conventional architecture.

Yang Yang - One of the best experts on this subject based on the ideXlab platform.

  • an efficient triple junction Polymer Solar Cell having a power conversion efficiency exceeding 11
    Advanced Materials, 2014
    Co-Authors: Chun-chao Chen, Jingbi You, Ken Yoshimura, Jing Gao, Weihsuan Chang, Kenichiro Ohya, Zirou Hong, Yang Yang
    Abstract:

    Tandem Solar Cells have the potential to improve photon conversion efficiencies (PCEs) beyond the limits of single-junction devices. In this study, a triple-junction tandem design is demonstrated by employing three distinct organic donor materials having bandgap energies ranging from 1.4 to 1.9 eV. Through optical modeling, balanced photon absorption rates are achieved and, thereby, the photo-currents are matched among the three subCells. Accordingly, an efficient triple-junction tandem organic Solar Cell can exhibit a record-high PCE of 11.5%.

  • Polymer Solar Cells
    Nature Photonics, 2012
    Co-Authors: Rui Zhu, Yang Yang
    Abstract:

    This Review summarizes recent progress in the development of Polymer Solar Cells. It covers the scientific origins and basic properties of Polymer Solar Cell technology, material requirements and device operation mechanisms, while also providing a synopsis of major achievements in the field over the past few years. Potential future developments and the applications of this technology are also briefly discussed.

  • interface investigation and engineering achieving high performance Polymer photovoltaic devices
    Journal of Materials Chemistry, 2010
    Co-Authors: Limin Chen, Zheng Xu, Ziruo Hong, Yang Yang
    Abstract:

    The contact between the Polymer active layer and the electrode is one the most critical interfaces in Polymer Solar Cells. In this article, we report the progress of interface engineering in Polymer Solar Cell research, where the multiple functions of the interfacial materials will be discussed. The vertical composition profile in Polymer:fullerene blends is an emerging topic, and the interlayer effect on the vertical phase separation and device performance will be highlighted. We also discuss the energy level alignment at the bulk heterojunction (BHJ) interface, with the aim of providing a better understanding towards the route of high efficiency Polymer Solar Cells.

  • zno nano ridge structure and its application in inverted Polymer Solar Cell
    Organic Electronics, 2009
    Co-Authors: Nobuyuki Sekine, Chenghsuan Chou, Wei Lek Kwan, Yang Yang
    Abstract:

    We report a unique nano-ridge structure of zinc oxide (ZnO) and its application in high performance inverted Polymer Solar Cells. The ZnO nano-ridge structure was formed by a sol– gel process using a ramp annealing method. As the solvent slowly evaporated due to the low heating rate, there was sufficient time for the gel particles to structurally relax and pile up, resulting in a dense and undulated film. Nano-ridges with peak as high as 120 nm and valley to valley distance of about 500 nm were formed. This film provided an effective hole blocking layer and also an increased interfacial area for electron collection. An inverted bulk heterojunction Polymer Solar Cell was fabricated using the ZnO nano-ridge film as the electron collecting layer. The device showed a high power conversion efficiency of 4.00%, an improvement of about 25% over similar Solar Cells made with a planar film of ZnO nanoparticles.

  • Polymer Solar Cells with enhanced open circuit voltage and efficiency
    Nature Photonics, 2009
    Co-Authors: Hsiangyu Chen, Shaoqing Zhang, Yongye Liang, Guanwen Yang, Yang Yang, Luping Yu, Yue Wu, Gang Li
    Abstract:

    Following the development of the bulk heterojunction1 structure, recent years have seen a dramatic improvement in the efficiency of Polymer Solar Cells. Maximizing the open-circuit voltage in a low-bandgap Polymer is one of the critical factors towards enabling high-efficiency Solar Cells. Study of the relation between open-circuit voltage and the energy levels of the donor/acceptor2 in bulk heterojunction Polymer Solar Cells has stimulated interest in modifying the open-circuit voltage by tuning the energy levels of Polymers3. Here, we show that the open-circuit voltage of Polymer Solar Cells constructed based on the structure of a low-bandgap Polymer, PBDTTT4, can be tuned, step by step, using different functional groups, to achieve values as high as 0.76 V. This increased open-circuit voltage combined with a high short-circuit current density results in a Polymer Solar Cell with a power conversion efficiency as high as 6.77%, as certified by the National Renewable Energy Laboratory. Adding electron-withdrawing groups to the backbone of the Polymer PBDTTT is shown to increase the open-circuit voltage of photovoltaic Cells, resulting in a Polymer Solar-Cell that has a certified power-conversion efficiency of 6.77%.

Shaoqing Zhang - One of the best experts on this subject based on the ideXlab platform.

  • fullerene free Polymer Solar Cells with over 11 efficiency and exCellent thermal stability
    Advanced Materials, 2016
    Co-Authors: Wenchao Zhao, Olle Inganäs, Shaoqing Zhang, Deping Qian, Sunsun Li, Feng Gao, Jianhui Hou
    Abstract:

    A nonfullerene-based Polymer Solar Cell (PSC) that significantly outperforms fullerene-based PSCs with respect to the power-conversion efficiency is demonstrated for the first time. An efficiency o ...

  • fullerene free Polymer Solar Cells with over 11 efficiency and exCellent thermal stability
    Advanced Materials, 2016
    Co-Authors: Wenchao Zhao, Olle Inganäs, Shaoqing Zhang, Deping Qian, Feng Gao, Jianhui Hou
    Abstract:

    A nonfullerene-based Polymer Solar Cell (PSC) that significantly outperforms fullerene-based PSCs with respect to the power-conversion efficiency is demonstrated for the first time. An efficiency of >11%, which is among the top values in the PSC field, and exCellent thermal stability is obtained using PBDB-T and ITIC as donor and acceptor, respectively.

  • Enhanced Efficiency in Fullerene-Free Polymer Solar Cell by Incorporating Fine-designed Donor and Acceptor Materials
    ACS applied materials & interfaces, 2015
    Co-Authors: Kai Sun, Shaoqing Zhang, Wei Jiang, Wenchao Zhao, Huifeng Yao, Zhaohui Wang, Jianhui Hou
    Abstract:

    Among the diverse nonfullerene acceptors, perylene bisimides (PBIs) have been attracting much attention due to their exCellent electron mobility and tunable molecular and electronic properties by simply engineering the bay and head linkages. Herein, guided by two efficient small molecular acceptors, we designed, synthesized, and characterized a new nonfullerene small molecule PPDI with fine-tailored alkyl chains. Notably, a certificated PCE of 5.40% is realized in a simple structured fullerene-free Polymer Solar Cell comprising PPDI as the electron acceptor and a fine-tailored 2D-conjugated Polymer PBDT-TS1 as the electron donor. Moreover, the device behavior, morphological feature, and origin of high efficiency in PBDT-TS1/PPDI-based fullerene-free PSC were investigated. The synchronous selection and design of donor and acceptor materials reported here offer a feasible strategy for realizing highly efficient fullerene-free organic photovoltaics.

  • realizing over 10 efficiency in Polymer Solar Cell by device optimization
    Science China-chemistry, 2015
    Co-Authors: Shaoqing Zhang, Jianhui Hou, Wenchao Zhao, Bei Yang, Qi Wang
    Abstract:

    The low band gap Polymer based on benzodithiophene (BDT)-thieno[3,4-b]thiophene (TT) backbone, PBDT-TS1, was synthesized following our previous work and the bulk heterojunction (BHJ) material comprising PBDT-TS1/PC71BM was optimized and characterized. By processing the active layer with different additives i.e. 1,8-diiodooctane (DIO), 1-chloronaphthalene (CN) and 1, 8-octanedithiol (ODT) and optimizing the ratio of each additive in the host solvent, a high PCE of 9.98% was obtained under the condition of utilizing 3% DIO as processing additive in CB. The effect of varied additives on photovoltaic performance was illustrated with atomic force microscopy (AFM) and transmission electron microscope (TEM) measurements that explained changes in photovoltaic parameters. These results provide valuable information of solvent additive choice in device optimization of PBDTTT Polymers, and the systematic device optimization could be applied in other efficient photovoltaic Polymers. Apparently, this work presents a great advance in single junction PSCs, especially in PSCs with conventional architecture.

  • enhanced photovoltaic performance by modulating surface composition in bulk heterojunction Polymer Solar Cells based on pbdttt c t pc71bm
    Advanced Materials, 2014
    Co-Authors: Xia Guo, Shaoqing Zhang, Maojie Zhang, Shengjian Liu, Harald Ade, Fei Huang, Jianhui Hou
    Abstract:

    For the blend film of PBDTTT-C-T:PC71 BM, the use of 1,8-diiodooctane as the solvent additive enriches the Polymer at the top surface, so that a power conversion efficiency of 9.13% is recorded in the inverted Polymer Solar Cell based on the blend, which is much higher than that of the device with conventional structure.

Mikkel Jorgensen - One of the best experts on this subject based on the ideXlab platform.

  • Scalability and stability of very thin, roll-to-roll processed, large area, indium-tin-oxide free Polymer Solar Cell modules
    Organic Electronics: physics materials applications, 2013
    Co-Authors: Dechan Angmo, Thue T. Larsen-olsen, Markus Hösel, Suren A Gevorgyan, Roar R Sondergaard, Giridhar U. Kulkarni, Ritu Gupta, Mikkel Jorgensen, Frederik C Krebs
    Abstract:

    Polymer Solar Cell modules were prepared directly on thin flexible barrier polyethylene terephthalate foil. The performance of the modules was found to be scalable from a single Cell with an area of 6 cm2to modules with a total area of up to 186 cm2. The substrate thickness was also explored and the performance was found to be independent of thickness in the range of 20-130 μm. The thinner substrates were found to present some challenge regarding handling but were not limited in performance. Large area modules on a substrate thickness of 45 μm were finally prepared by full roll-to-roll processing employing P3HT:PCBM as the active material and were found to exhibit a total area efficiency of >1% (1000 W/m-2; AM1.5G) with a typical active-area efficiency in the 1.5-1.6% for total module area of >110 cm2due to high fill factors in excess of 50%. The modules were also found to have an active-area efficiency of >1% under low light levels (∼100 W m-2). The modules were then subjected to extensive stability testing for a minimum of 1000 h employing several ISOS protocols. The modules presented higher than 80% of the initial performance (T80) in the dark (ISOS-D-1), in dark under elevated temperature of 65°C (ISOS-D-2), under low light (ISOS-LL), under full sunlight (ISOS-L-2), and under outdoor testing (ISOS-O), which was conducted in two locations in India and Denmark. We estimate maximum T80 for those tests to be 2800, 5000, 1300, 1000, and 3500 h respectively. The modules showed significant sensitivity to high humidity and had low values for T80 for dark storage tests at 50°C/85%RH (ISOS-D-3) and accelerated operation conditions with 0.7 sun/65 oC/50%RH (ISOS-L-3). We found the modules to be particularly suited for information and communications technology (ICT) and mobile applications where low humidity (

  • a laboratory scale approach to Polymer Solar Cells using one coating printing machine flexible substrates no ito no vacuum and no spincoating
    Solar Energy Materials and Solar Cells, 2013
    Co-Authors: Jon Eggert Carle, Mikkel Jorgensen, Martin Helgesen, Thomas Rieks Andersen, Eva Bundgaard, Frederik C Krebs
    Abstract:

    Abstract Printing of the silver back electrode under ambient conditions using simple laboratory equipment has been the missing link to fully replace evaporated metal electrodes. Here we demonstrate how a recently developed roll coater is further developed into a single machine that enables processing of all layers of the Polymer Solar Cell without moving the substrate from one machine to another. The novel approach to Polymer Solar Cells is readily scalable using one compact laboratory scale coating/printing machine that is directly compatible with industrial and pilot scale roll-to-roll processing. The use of the techniques was successfully demonstrated in one continuous roll process on flexible polyethyleneterphthalate (PET) substrates and Polymer Solar Cells were prepared by solution processing of five layers using only slot-die coating and flexographic printing. The devices obtained did not employ indium–tin-oxide (ITO) or vacuum evaporation steps making it a significant step beyond the traditional laboratory Polymer Solar Cell processing methods involving spin coating and metal evaporation.

  • edge sealing for low cost stability enhancement of roll to roll processed flexible Polymer Solar Cell modules
    Solar Energy Materials and Solar Cells, 2012
    Co-Authors: David M Tanenbaum, Mikkel Jorgensen, Henrik Friis Dam, Roland Rosch, Harald Hoppe, Frederik C Krebs
    Abstract:

    Abstract Fully roll-to-roll processed Polymer Solar Cell modules were prepared, characterized, and laminated. Cell modules were cut from the roll and matched pairs were selected, one module with exposed cut edges, the other laminated again with the same materials and adhesive sealing fully around the cut edges. The edge sealing rim was 10 mm wide. Cell modules were characterized by periodic measurements of IV curves over extended periods in a variety of conditions, as well as by a variety of spatial imaging techniques. Data show significant stability benefits of the edge sealing process. The results of the imaging experiments show that the ingress of atmospheric reactants from the edges leads to degradation. In the case of edge sealed devices the same effects are observed but significantly slowed down. In particular, the fast nonlinear degradation is eliminated.

  • fabrication of Polymer Solar Cells using aqueous processing for all layers including the metal back electrode
    Advanced Energy Materials, 2011
    Co-Authors: Roar R Sondergaard, Mikkel Jorgensen, Martin Helgesen, Frederik C Krebs
    Abstract:

    Utilization of sunlight as an energy source is one of the least exploited carbon-neutral methods available today. The potential is enormous, with a wide range of possible applications such as large scale energy production, small standalone energy production units in remote areas situated ‘off the power grid’ or tiny power production units aimed at recharging small electronic equipment that we surround ourselves with. Over recent years Polymer and organic Solar Cells have been perfected at the laboratory level and the performance now approaches many of the inorganic thin fi lm Solar Cells. It has been argued that the ∼ 8% power conversion effi ciency recently reported for Polymer Solar Cells might challenge polycrystalline silicon when projecting the steady increase in Polymer Solar Cell performance a few years into the future. Many challenges remain that have to be addressed effi ciently before the vision of large scale manufacture and widespread usage of low cost Polymer Solar Cells can be anticipated. Ideally the Polymer Solar Cell should be manufactured in a fast, large-area, environmentally friendly process. The methodologies employed in typical laboratory studies do not represent this well. The most commonly employed fi lm forming technique is spin-coating which is incompatible with large areas, large volume, and low cost. Another troublesome aspect is the use of toxic organic solvents in the fi lm-forming process. In the large-scale application where production volumes corresponding to several GW peak are envisaged this is not a viable approach and alternative solvents will be a requirement. Until now, solvent-free or environmentally friendly solvent processing have not been studied to any signifi cant level. An explanation for this can possibly be sought in the delicate interplay between the processing solvent and the performance of the Solar Cell. In many ways the state-ofthe-art Polymer Solar Cell has evolved around aromatic solvents such as chlorobenzene, dichlorobenzene, toluene, and xylene. Any change of solvent adversely affects the nanomorphology of the fi lm and the device performance. The ambition to use more benign solvents would require a redesign of the molecular structures and a re-establishment of the interplay between nanomorphology and processing for the new material-solvent

  • upscaling of Polymer Solar Cell fabrication using full roll to roll processing
    Nanoscale, 2010
    Co-Authors: Frederik C Krebs, Thomas Tromholt, Mikkel Jorgensen
    Abstract:

    Upscaling of the manufacture of Polymer Solar Cells is detailed with emphasis on cost analysis and practical approach. The device modules were prepared using both slot-die coating and screen printing the active layers in the form of stripes that were serially connected. The stripe width was varied and the resultant performance analysed. Wider stripes give access to higher geometric fill factors and lower aperture loss while they also present larger sheet resistive losses. An optimum was found through preparation of serially connected stripes having widths of 9, 13 and 18 mm with nominal geometric fill factors (excluding bus bars) of 50, 67 and 75% respectively. In addition modules with lengths of 6, 10, 20, 22.5 and 25 cm were explored. The devices were prepared by full roll-to-roll solution processing in a web width of 305 mm and roll lengths of up to 200 m. The devices were encapsulated with a barrier material in a full roll-to-roll process using standard adhesives giving the devices exCellent stability during storage and operation. The total area of processed Polymer Solar Cell was around 60 m2 per run. The Solar Cells were characterised using a roll-to-roll system comprising a Solar simulator and an IV-curve tracer. After characterisation the Solar Cell modules were cut into sheets using a sheeting machine and contacted using button contacts applied by crimping. Based on this a detailed cost analysis was made showing that it is possible to prepare complete and contacted Polymer Solar Cell modules on this scale at an area cost of 89 € m−2 and an electricity cost of 8.1 € Wp−1. The cost analysis was separated into the manufacturing cost, materials cost and also the capital investment required for setting up a complete production plant on this scale. Even though the cost in € Wp−1 is comparable to the cost for electricity using existing technologies the levelized cost of electricity (LCOE) is expected to be significantly higher than the existing technologies due to the inferior operational lifetime. The presented devices are thus competitive for consumer electronics but ill-suited for on-grid electricity production in their current form.