Progress in Photovoltaics: Research and Applications, 2013
New generation photovoltaic (PV) devices such as polymer and dye sensitized solar cells (DSC) hav... more New generation photovoltaic (PV) devices such as polymer and dye sensitized solar cells (DSC) have now reached a more mature stage of development, and among their various applications, building integrated PVs seems to have the most promising future, especially for DSC devices. This new generation technology has attracted an increasing interest because of its low cost due to the use of cheap printable materials and simple manufacturing techniques, easy production, and relatively high efficiency. As for the more consolidated PV technologies, DSCs need to be tested in real operating conditions and their performance compared with other PV technologies to put into evidence the real potential. This work presents the results of a 3 months outdoor monitoring activity performed on a DSC mini-panel made by the Dyepower Consortium, positioned on a south oriented vertical plane together with a double junction amorphous silicon (a-Si) device and a multi-crystalline silicon (m-Si) device at the ESTER station of the University of Rome Tor Vergata. Good performance of the DSC mini-panel has been observed for this particular configuration, where the DSC energy production compares favorably with that of a-Si and m-Si especially at high solar angles of incidence confirming the suitability of this technology for the integration into building facades. This assumption is confirmed by the energy produced per nominal watt-peak for the duration of the measurement campaign by the DSC that is 12% higher than that by a-Si and only 3% lower than that by m-Si for these operating conditions.
Dye-sensitized and perovskite solar cells have seen tremendous efforts in their development in re... more Dye-sensitized and perovskite solar cells have seen tremendous efforts in their development in recent years. Amongst these developments are the design and implementation of fabrication techniques that can guarantee high performance as well as scalability over large areas. Laser processing has become a versatile and important tool in many industries and has also been applied successfully to both types of solar cell technologies, culminating in the demonstration of dye solar devices where all temperature treatments have been replaced with laser techniques, and of high-performance solid-state perovskite modules. Herein, we introduce concepts and review the available literature, pertaining to the effective utilization of laser beams for the development of both dye-sensitized and perovskite photovoltaic technologies.
Phthalocyanines based-dyes represent attractive alternatives to the expensive and polluting pyrid... more Phthalocyanines based-dyes represent attractive alternatives to the expensive and polluting pyridyl based Ru complexes because of their photochemical and thermal stability, they do show in fact intense absorption in the UV/blue (Soret band) and the red/near IR (Q band) spectral regions and appear very promising as sensitizer dyes for DSSC. In this contribution we review the state of the art and the recent progress in the application of these materials as dyes for DSSC and present three new dyes which are bridged derivatives of Iron phthalocyanine. Synthesis, optical properties, electrochemical characterization and device performances are discussed with regard to the different substitution degree of the macrocycle.
Citazione: Di Carlo, A., Brown, TM, Reale, A., Brunetti, A., D'Ercole, D., Dominici, L.,... more Citazione: Di Carlo, A., Brown, TM, Reale, A., Brunetti, A., D'Ercole, D., Dominici, L., et al.(2009). Photocurrent enhancement of dye solar cells by efficient light management. Paper presented at PLMCN9. 9th International Conference on Physics of Light-Matter Coupling ...
Indium tin oxide (ITO), Au and Pt are materials of interest as high work function contacts for or... more Indium tin oxide (ITO), Au and Pt are materials of interest as high work function contacts for organic semiconductor devices. In this paper the relative energy level line-up of these materials is investigated both as bare surfaces or part of a polymer/conductor interface. Kelvin probe (KP) measurements show that the estimated work function for Au and Pt surfaces, evaporated under normal high vacuum (HV) fabrication conditions and measured in air, can be significantly lower (by $0.2 to 0.9 eV) than those of clean surfaces evaporated and measured in the more demanding and clean ultra high vacuum (UHV), that are often used as reference values. The work function of all surfaces increases significantly (from $0.4 to >1 eV) after an oxygen plasma, but then decreases upon air exposure, with different rates for different materials. The effect of the plasma wears off most rapidly for Au whilst it is more resilient for ITO. Most interestingly, via KP and electroabsorption measurements of the built-in potential on polymer/conductor and conductor/polymer/conductor structures, we demonstrate that a plasma-induced enhancement of the work function is ''frozen in'' by the application of a polymer semiconductor layer over the plasma-treated surfaces and can be made to last for years by proper device encapsulation. These results have strong implications on the understanding, fabrication, design and stability of organic semiconductor devices.
In this paper we analyze the interplay between transparency and efficiency in dye sensitized sola... more In this paper we analyze the interplay between transparency and efficiency in dye sensitized solar cells by varying fabrication parameters such as the thickness of the nano-crystalline TiO 2 layer, the dye loading and the dye type. Both transparency and efficiency show a saturation trend when plotted versus dye loading. By introducing the transparencyefficiency plot, we show that the relation between transparency and efficiency is linear and is almost independent on the TiO 2 thickness for a certain thickness range. On the contrary, the relation between transparency and efficiency depends strongly on the type of the dye. Moreover, we show that co-sensitization techniques can be effectively used to access regions of the transparency-efficiency space that are forbidden for single dye sensitization. The relation found between transparency and efficiency (T&E) can be the general guide for optimization of Dye Solar Cells in building integration applications.
We quantify the strong dependence of photocurrent on the angle of incidence of light in a dye sol... more We quantify the strong dependence of photocurrent on the angle of incidence of light in a dye solar cell ͑DSC͒. Under laser illumination the photocurrent increases for large incidence angles. The enhancements are different upon using or not a coupling prism. They are explained with a model including three different angular factors. The observed enhancements up to 25% can be useful for evaluating novel designs of an efficient photon management in DSCs. Even an effective refractive index n eff Ϸ 2.0 for the mesoporous titania/electrolyte phase was retrieved from the angle dependent photocurrent.
ABSTRACT The challenge of increasing the photocurrent of a dye solar cell device by acting on the... more ABSTRACT The challenge of increasing the photocurrent of a dye solar cell device by acting on the spectral response is approached herein. Cosensitization of nanocrystalline titania photoanodes by using two complementary dyes is investigated considering the dyeing time as an additional parameter for the optimization of the cosensitization process. We find that the characteristics of the cosensitized cell can outperform those of the cells made with each single dye. This effect is related to the reduction of the molecular stacking of one of the dyes, which quenches electron transfer to TiO2. Cosensitization results are also related to the cell transparency.
Progress in Photovoltaics: Research and Applications, 2013
New generation photovoltaic (PV) devices such as polymer and dye sensitized solar cells (DSC) hav... more New generation photovoltaic (PV) devices such as polymer and dye sensitized solar cells (DSC) have now reached a more mature stage of development, and among their various applications, building integrated PVs seems to have the most promising future, especially for DSC devices. This new generation technology has attracted an increasing interest because of its low cost due to the use of cheap printable materials and simple manufacturing techniques, easy production, and relatively high efficiency. As for the more consolidated PV technologies, DSCs need to be tested in real operating conditions and their performance compared with other PV technologies to put into evidence the real potential. This work presents the results of a 3 months outdoor monitoring activity performed on a DSC mini-panel made by the Dyepower Consortium, positioned on a south oriented vertical plane together with a double junction amorphous silicon (a-Si) device and a multi-crystalline silicon (m-Si) device at the ESTER station of the University of Rome Tor Vergata. Good performance of the DSC mini-panel has been observed for this particular configuration, where the DSC energy production compares favorably with that of a-Si and m-Si especially at high solar angles of incidence confirming the suitability of this technology for the integration into building facades. This assumption is confirmed by the energy produced per nominal watt-peak for the duration of the measurement campaign by the DSC that is 12% higher than that by a-Si and only 3% lower than that by m-Si for these operating conditions.
Dye-sensitized and perovskite solar cells have seen tremendous efforts in their development in re... more Dye-sensitized and perovskite solar cells have seen tremendous efforts in their development in recent years. Amongst these developments are the design and implementation of fabrication techniques that can guarantee high performance as well as scalability over large areas. Laser processing has become a versatile and important tool in many industries and has also been applied successfully to both types of solar cell technologies, culminating in the demonstration of dye solar devices where all temperature treatments have been replaced with laser techniques, and of high-performance solid-state perovskite modules. Herein, we introduce concepts and review the available literature, pertaining to the effective utilization of laser beams for the development of both dye-sensitized and perovskite photovoltaic technologies.
Phthalocyanines based-dyes represent attractive alternatives to the expensive and polluting pyrid... more Phthalocyanines based-dyes represent attractive alternatives to the expensive and polluting pyridyl based Ru complexes because of their photochemical and thermal stability, they do show in fact intense absorption in the UV/blue (Soret band) and the red/near IR (Q band) spectral regions and appear very promising as sensitizer dyes for DSSC. In this contribution we review the state of the art and the recent progress in the application of these materials as dyes for DSSC and present three new dyes which are bridged derivatives of Iron phthalocyanine. Synthesis, optical properties, electrochemical characterization and device performances are discussed with regard to the different substitution degree of the macrocycle.
Citazione: Di Carlo, A., Brown, TM, Reale, A., Brunetti, A., D'Ercole, D., Dominici, L.,... more Citazione: Di Carlo, A., Brown, TM, Reale, A., Brunetti, A., D'Ercole, D., Dominici, L., et al.(2009). Photocurrent enhancement of dye solar cells by efficient light management. Paper presented at PLMCN9. 9th International Conference on Physics of Light-Matter Coupling ...
Indium tin oxide (ITO), Au and Pt are materials of interest as high work function contacts for or... more Indium tin oxide (ITO), Au and Pt are materials of interest as high work function contacts for organic semiconductor devices. In this paper the relative energy level line-up of these materials is investigated both as bare surfaces or part of a polymer/conductor interface. Kelvin probe (KP) measurements show that the estimated work function for Au and Pt surfaces, evaporated under normal high vacuum (HV) fabrication conditions and measured in air, can be significantly lower (by $0.2 to 0.9 eV) than those of clean surfaces evaporated and measured in the more demanding and clean ultra high vacuum (UHV), that are often used as reference values. The work function of all surfaces increases significantly (from $0.4 to >1 eV) after an oxygen plasma, but then decreases upon air exposure, with different rates for different materials. The effect of the plasma wears off most rapidly for Au whilst it is more resilient for ITO. Most interestingly, via KP and electroabsorption measurements of the built-in potential on polymer/conductor and conductor/polymer/conductor structures, we demonstrate that a plasma-induced enhancement of the work function is ''frozen in'' by the application of a polymer semiconductor layer over the plasma-treated surfaces and can be made to last for years by proper device encapsulation. These results have strong implications on the understanding, fabrication, design and stability of organic semiconductor devices.
In this paper we analyze the interplay between transparency and efficiency in dye sensitized sola... more In this paper we analyze the interplay between transparency and efficiency in dye sensitized solar cells by varying fabrication parameters such as the thickness of the nano-crystalline TiO 2 layer, the dye loading and the dye type. Both transparency and efficiency show a saturation trend when plotted versus dye loading. By introducing the transparencyefficiency plot, we show that the relation between transparency and efficiency is linear and is almost independent on the TiO 2 thickness for a certain thickness range. On the contrary, the relation between transparency and efficiency depends strongly on the type of the dye. Moreover, we show that co-sensitization techniques can be effectively used to access regions of the transparency-efficiency space that are forbidden for single dye sensitization. The relation found between transparency and efficiency (T&E) can be the general guide for optimization of Dye Solar Cells in building integration applications.
We quantify the strong dependence of photocurrent on the angle of incidence of light in a dye sol... more We quantify the strong dependence of photocurrent on the angle of incidence of light in a dye solar cell ͑DSC͒. Under laser illumination the photocurrent increases for large incidence angles. The enhancements are different upon using or not a coupling prism. They are explained with a model including three different angular factors. The observed enhancements up to 25% can be useful for evaluating novel designs of an efficient photon management in DSCs. Even an effective refractive index n eff Ϸ 2.0 for the mesoporous titania/electrolyte phase was retrieved from the angle dependent photocurrent.
ABSTRACT The challenge of increasing the photocurrent of a dye solar cell device by acting on the... more ABSTRACT The challenge of increasing the photocurrent of a dye solar cell device by acting on the spectral response is approached herein. Cosensitization of nanocrystalline titania photoanodes by using two complementary dyes is investigated considering the dyeing time as an additional parameter for the optimization of the cosensitization process. We find that the characteristics of the cosensitized cell can outperform those of the cells made with each single dye. This effect is related to the reduction of the molecular stacking of one of the dyes, which quenches electron transfer to TiO2. Cosensitization results are also related to the cell transparency.
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