The investigation of degradation of seven distinct sets (with a number of individual cells of n≥ ... more The investigation of degradation of seven distinct sets (with a number of individual cells of n≥ 12) of state of the art organic photovoltaic devices prepared by leading research laboratories with a combination of imaging methods is reported. All devices have been ...
Structure dependence in hybrid Si nanowire/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate... more Structure dependence in hybrid Si nanowire/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) solar cells: Understanding photovoltaic conversion in nanowire radial junctions Appl. Phys. Lett. 100, 023112 (2012) Dependence of recombination mechanisms and strength on processing conditions in polymer solar cells APL: Org. Electron. Photonics 4, 279 (2011) Dependence of recombination mechanisms and strength on processing conditions in polymer solar cells Appl. Phys. Lett. 99, 263301 (2011) Crystal particle Raman-scattering and applications for improved solar cell performance Appl. Phys. Lett. 99, 251109 (2011) Effects of aging on the mobility and lifetime of carriers in organic bulk heterojunction solar cells J. Renewable Sustainable Energy 3, 063111 (2011) Additional information on Appl. Phys. Lett.
A study of the photonic flash sintering of a silver nanoparticle ink printed as the back electrod... more A study of the photonic flash sintering of a silver nanoparticle ink printed as the back electrode for organic solar cells is presented. A number of sintering settings with different intensities and pulse durations have been tested on both full-area and grid-based silver electrodes, using the complete emission spectrum of the flash lamps from UV-A to NIR. However, none of these settings was able to produce functional devices with performances comparable to those of reference cells prepared using thermally sintered ink. Different degradation mechanisms were detected in the devices with a flash-sintered back electrode. The P3HT:PCBM photoactive layer appears to be highly heat-sensitive and turned out to be severely damaged by the high temperatures generated in the silver layer during the sintering. In addition, UV-induced photochemical degradation of the functional materials was identified as another possible source of performance deterioration in the devices with grid-based electrodes. Reducing the light intensity does not provide a proper solution because in this case the Ag electrode is not sintered sufficiently. For both types of devices, with full-area and grid-based electrodes, these problems could be solved by excluding the short wavelength contribution from the flash light spectrum using a filter. Optimized sintering parameters allowed manufacture of OPV devices with performance equal to those of the reference devices. Photonic flash sintering of the top electrode in organic solar cells was demonstrated for the first time. It reveals the great potential of this sintering method for the future roll-to-roll manufacturing of organic solar cells from solution.
Intrinsic light stability of transparent MoO3/Ag/TiO2 electrode is studied in four different poly... more Intrinsic light stability of transparent MoO3/Ag/TiO2 electrode is studied in four different polymer:fullerene solar cell configurations. We demonstrate that this stack can successfully replace ITO both in superstrate and substrate configurations required for non-transparent carriers. Although we observe that exposure of thin Ag layer directly to UV light reduces its conductivity, integration of a UV filter in the device package mitigates entirely this failure route. This enables us to show efficient and stable ITO-free cells both in superstrate and substrate configurations can reach identical stability as the ITO reference.
ABSTRACT The present invention discloses an apparatus for indicating the passage of time, compris... more ABSTRACT The present invention discloses an apparatus for indicating the passage of time, comprising a substrate and an indicating layer formed on the substrate. The indicating layer comprises a polymer matrix and a predetermined amount of redox compound under the reduced form. The redox compound is dispersed in the polymer matrix and has the following properties: the reduced form of the redox compound reacts with oxygen to form the oxidized form of the redox compound; the hue or color density of the reduced form of the redox compound is different from that of the oxidized form of the redox compound; and the hue or color density of the indicating layer varies as the time for the reduced form of the redox compound contacting with oxygen in environment increases to have the amount of the oxidized form of the redox compound increase so as to indicate the passage of time.
Conference Record of the IEEE Photovoltaic Specialists Conference
Large-area organic solar cells are known to suffer from a major efficiency decrease which origina... more Large-area organic solar cells are known to suffer from a major efficiency decrease which originates from the combination of a voltage drop across the front electrode and the voltage-dependent photocurrent. In this letter, we demonstrate this efficiency loss on large area, indium tin oxide free cells with a hexagonal current collecting front grid, by measurements of light intensity dependence of the cell performance. The results show a major difference in the cell performance measured under localized and uniform illuminations. Subsequently, we demonstrate ways in which the current collecting efficiency could be raised.
Indium-tin-oxide (ITO) free polymer solar cells prepared by ink jet printing a composite front el... more Indium-tin-oxide (ITO) free polymer solar cells prepared by ink jet printing a composite front electrode comprising silver grid lines and a semitransparent PEDOT:PSS conductor are demonstrated. The effect of grid line density is explored for a large series of devices and a careful modeling study enabling the identifi cation of the most rational grid structure is presented. Both optical and light beam induced current (LBIC) mapping of the devices are used to support the power loss model and to follow the evolution of the performance over time. Current generation is found to be evenly distributed over the active area initially progressing to a larger graduation in areas with different performance. Over time coating defects also become much more apparent in the LBIC images.
Indium-tin-oxide (ITO) free polymer solar cells prepared by ink jet printing a composite front el... more Indium-tin-oxide (ITO) free polymer solar cells prepared by ink jet printing a composite front electrode comprising silver grid lines and a semitransparent PEDOT:PSS conductor are demonstrated. The effect of grid line density is explored for a large series of devices and a careful modeling study enabling the identification of the most rational grid structure is presented. Both optical and light beam induced current (LBIC) mapping of the devices are used to support the power loss model and to follow the evolution of the performance over time. Current generation is found to be evenly distributed over the active area initially progressing to a larger graduation in areas with different performance. Over time coating defects also become much more apparent in the LBIC images. . Typical degradation profile for the devices under highly accelerated conditions AM1.5G, 1000 W m −2 , 85 ± 2 °C, 45 ± 5% RH.
ABSTRACT The present invention discloses a time passage indicating apparatus which comprises a su... more ABSTRACT The present invention discloses a time passage indicating apparatus which comprises a substrate, a background layer on the substrate, and a time passage indicating layer on the background layer. The background layer and the time passage indicating layer bond to each other through a first and second polymer binder. The background layer displays a background color. The time passage indicating layer displays an initial color in an initial state that is different from the background color, and a final color in a final state that is substantially the same as the background color, so as to indicate the end of a time period where the time passage indicating layer transforms from the initial state to the final state.
ABSTRACT The present invention discloses an apparatus for indicating the passage of time, compris... more ABSTRACT The present invention discloses an apparatus for indicating the passage of time, comprising a substrate and an indicating layer formed on the substrate. The indicating layer comprises a polymer matrix and a predetermined amount of redox compound under the reduced form. The redox compound is dispersed in the polymer matrix and has the following properties: the reduced form of the redox compound reacts with oxygen to form the oxidized form of the redox compound; the hue or color density of the reduced form of the redox compound is different from that of the oxidized form of the redox compound; and the hue or color density of the indicating layer varies as the time for the reduced form of the redox compound contacting with oxygen in environment increases to have the amount of the oxidized form of the redox compound increase so as to indicate the passage of time.
ABSTRACT A thin film solar cell module (1) is disclosed that is substantially translucent in at l... more ABSTRACT A thin film solar cell module (1) is disclosed that is substantially translucent in at least a first wavelength domain. The module comprises a photo-electric layer (20) arranged for receiving solar radiation and for converting solar radiation in at least a second wavelength domain different from the at least a first wavelength domain into electric energy and a selectively reflective layer (30) arranged against the photo-electric layer for selectively reflecting radiation in said second wavelength domain transmitted by the photo-electric layer. The module further comprises a further photo-electric layer (40) for absorbing and converting radiation in at least the second wavelength domain into electric energy, the selectively reflective layer (30) being arranged between the photo-electric layer (20) and the further photo-electric layer (40) wherein the at least a first wavelength domain comprises a first wavelength band from 350 nm to 500 nm and a second wavelength band from 600 nm to 700 nm and wherein the second wavelength domain comprises a wavelength range extending from 500 to 600 nm.
To reduce the costs of polymer solar cells it is important to develop a fully solution processed ... more To reduce the costs of polymer solar cells it is important to develop a fully solution processed route. Although several successful generic routes to solution processed hole collecting electrodes have been shown, this is not the case for the electron collecting electrode of polymers cells, as it is hard to find a solution processable low workfunction, low ohmic, electron collecting electrode. Here an efficient recombination layer is described formed by the combination of ZnO and PEDOT and applied in an electron collecting layer. The ZnO contacts the conduction band of the acceptor material to collect electrons from the absorber layer. Since ZnO is a wide bandgap material, it also acts as an exciton and hole blocking layer. Electrons collected by the ZnO layer easily recombine with holes from the highly doped, high conductive PEDOT layer. The performance of a device with a recombination layer is compared in a standard as well as inverted polymer solar cells. The performance of the device with the PEDOT/ZnO recombination layer deviates less than 10 % from similarly processed standard and inverted device structures.
The investigation of degradation of seven distinct sets (with a number of individual cells of n≥ ... more The investigation of degradation of seven distinct sets (with a number of individual cells of n≥ 12) of state of the art organic photovoltaic devices prepared by leading research laboratories with a combination of imaging methods is reported. All devices have been ...
Structure dependence in hybrid Si nanowire/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate... more Structure dependence in hybrid Si nanowire/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) solar cells: Understanding photovoltaic conversion in nanowire radial junctions Appl. Phys. Lett. 100, 023112 (2012) Dependence of recombination mechanisms and strength on processing conditions in polymer solar cells APL: Org. Electron. Photonics 4, 279 (2011) Dependence of recombination mechanisms and strength on processing conditions in polymer solar cells Appl. Phys. Lett. 99, 263301 (2011) Crystal particle Raman-scattering and applications for improved solar cell performance Appl. Phys. Lett. 99, 251109 (2011) Effects of aging on the mobility and lifetime of carriers in organic bulk heterojunction solar cells J. Renewable Sustainable Energy 3, 063111 (2011) Additional information on Appl. Phys. Lett.
A study of the photonic flash sintering of a silver nanoparticle ink printed as the back electrod... more A study of the photonic flash sintering of a silver nanoparticle ink printed as the back electrode for organic solar cells is presented. A number of sintering settings with different intensities and pulse durations have been tested on both full-area and grid-based silver electrodes, using the complete emission spectrum of the flash lamps from UV-A to NIR. However, none of these settings was able to produce functional devices with performances comparable to those of reference cells prepared using thermally sintered ink. Different degradation mechanisms were detected in the devices with a flash-sintered back electrode. The P3HT:PCBM photoactive layer appears to be highly heat-sensitive and turned out to be severely damaged by the high temperatures generated in the silver layer during the sintering. In addition, UV-induced photochemical degradation of the functional materials was identified as another possible source of performance deterioration in the devices with grid-based electrodes. Reducing the light intensity does not provide a proper solution because in this case the Ag electrode is not sintered sufficiently. For both types of devices, with full-area and grid-based electrodes, these problems could be solved by excluding the short wavelength contribution from the flash light spectrum using a filter. Optimized sintering parameters allowed manufacture of OPV devices with performance equal to those of the reference devices. Photonic flash sintering of the top electrode in organic solar cells was demonstrated for the first time. It reveals the great potential of this sintering method for the future roll-to-roll manufacturing of organic solar cells from solution.
Intrinsic light stability of transparent MoO3/Ag/TiO2 electrode is studied in four different poly... more Intrinsic light stability of transparent MoO3/Ag/TiO2 electrode is studied in four different polymer:fullerene solar cell configurations. We demonstrate that this stack can successfully replace ITO both in superstrate and substrate configurations required for non-transparent carriers. Although we observe that exposure of thin Ag layer directly to UV light reduces its conductivity, integration of a UV filter in the device package mitigates entirely this failure route. This enables us to show efficient and stable ITO-free cells both in superstrate and substrate configurations can reach identical stability as the ITO reference.
ABSTRACT The present invention discloses an apparatus for indicating the passage of time, compris... more ABSTRACT The present invention discloses an apparatus for indicating the passage of time, comprising a substrate and an indicating layer formed on the substrate. The indicating layer comprises a polymer matrix and a predetermined amount of redox compound under the reduced form. The redox compound is dispersed in the polymer matrix and has the following properties: the reduced form of the redox compound reacts with oxygen to form the oxidized form of the redox compound; the hue or color density of the reduced form of the redox compound is different from that of the oxidized form of the redox compound; and the hue or color density of the indicating layer varies as the time for the reduced form of the redox compound contacting with oxygen in environment increases to have the amount of the oxidized form of the redox compound increase so as to indicate the passage of time.
Conference Record of the IEEE Photovoltaic Specialists Conference
Large-area organic solar cells are known to suffer from a major efficiency decrease which origina... more Large-area organic solar cells are known to suffer from a major efficiency decrease which originates from the combination of a voltage drop across the front electrode and the voltage-dependent photocurrent. In this letter, we demonstrate this efficiency loss on large area, indium tin oxide free cells with a hexagonal current collecting front grid, by measurements of light intensity dependence of the cell performance. The results show a major difference in the cell performance measured under localized and uniform illuminations. Subsequently, we demonstrate ways in which the current collecting efficiency could be raised.
Indium-tin-oxide (ITO) free polymer solar cells prepared by ink jet printing a composite front el... more Indium-tin-oxide (ITO) free polymer solar cells prepared by ink jet printing a composite front electrode comprising silver grid lines and a semitransparent PEDOT:PSS conductor are demonstrated. The effect of grid line density is explored for a large series of devices and a careful modeling study enabling the identifi cation of the most rational grid structure is presented. Both optical and light beam induced current (LBIC) mapping of the devices are used to support the power loss model and to follow the evolution of the performance over time. Current generation is found to be evenly distributed over the active area initially progressing to a larger graduation in areas with different performance. Over time coating defects also become much more apparent in the LBIC images.
Indium-tin-oxide (ITO) free polymer solar cells prepared by ink jet printing a composite front el... more Indium-tin-oxide (ITO) free polymer solar cells prepared by ink jet printing a composite front electrode comprising silver grid lines and a semitransparent PEDOT:PSS conductor are demonstrated. The effect of grid line density is explored for a large series of devices and a careful modeling study enabling the identification of the most rational grid structure is presented. Both optical and light beam induced current (LBIC) mapping of the devices are used to support the power loss model and to follow the evolution of the performance over time. Current generation is found to be evenly distributed over the active area initially progressing to a larger graduation in areas with different performance. Over time coating defects also become much more apparent in the LBIC images. . Typical degradation profile for the devices under highly accelerated conditions AM1.5G, 1000 W m −2 , 85 ± 2 °C, 45 ± 5% RH.
ABSTRACT The present invention discloses a time passage indicating apparatus which comprises a su... more ABSTRACT The present invention discloses a time passage indicating apparatus which comprises a substrate, a background layer on the substrate, and a time passage indicating layer on the background layer. The background layer and the time passage indicating layer bond to each other through a first and second polymer binder. The background layer displays a background color. The time passage indicating layer displays an initial color in an initial state that is different from the background color, and a final color in a final state that is substantially the same as the background color, so as to indicate the end of a time period where the time passage indicating layer transforms from the initial state to the final state.
ABSTRACT The present invention discloses an apparatus for indicating the passage of time, compris... more ABSTRACT The present invention discloses an apparatus for indicating the passage of time, comprising a substrate and an indicating layer formed on the substrate. The indicating layer comprises a polymer matrix and a predetermined amount of redox compound under the reduced form. The redox compound is dispersed in the polymer matrix and has the following properties: the reduced form of the redox compound reacts with oxygen to form the oxidized form of the redox compound; the hue or color density of the reduced form of the redox compound is different from that of the oxidized form of the redox compound; and the hue or color density of the indicating layer varies as the time for the reduced form of the redox compound contacting with oxygen in environment increases to have the amount of the oxidized form of the redox compound increase so as to indicate the passage of time.
ABSTRACT A thin film solar cell module (1) is disclosed that is substantially translucent in at l... more ABSTRACT A thin film solar cell module (1) is disclosed that is substantially translucent in at least a first wavelength domain. The module comprises a photo-electric layer (20) arranged for receiving solar radiation and for converting solar radiation in at least a second wavelength domain different from the at least a first wavelength domain into electric energy and a selectively reflective layer (30) arranged against the photo-electric layer for selectively reflecting radiation in said second wavelength domain transmitted by the photo-electric layer. The module further comprises a further photo-electric layer (40) for absorbing and converting radiation in at least the second wavelength domain into electric energy, the selectively reflective layer (30) being arranged between the photo-electric layer (20) and the further photo-electric layer (40) wherein the at least a first wavelength domain comprises a first wavelength band from 350 nm to 500 nm and a second wavelength band from 600 nm to 700 nm and wherein the second wavelength domain comprises a wavelength range extending from 500 to 600 nm.
To reduce the costs of polymer solar cells it is important to develop a fully solution processed ... more To reduce the costs of polymer solar cells it is important to develop a fully solution processed route. Although several successful generic routes to solution processed hole collecting electrodes have been shown, this is not the case for the electron collecting electrode of polymers cells, as it is hard to find a solution processable low workfunction, low ohmic, electron collecting electrode. Here an efficient recombination layer is described formed by the combination of ZnO and PEDOT and applied in an electron collecting layer. The ZnO contacts the conduction band of the acceptor material to collect electrons from the absorber layer. Since ZnO is a wide bandgap material, it also acts as an exciton and hole blocking layer. Electrons collected by the ZnO layer easily recombine with holes from the highly doped, high conductive PEDOT layer. The performance of a device with a recombination layer is compared in a standard as well as inverted polymer solar cells. The performance of the device with the PEDOT/ZnO recombination layer deviates less than 10 % from similarly processed standard and inverted device structures.
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Papers by Yulia Galagan