When embedded inside soft matter, molecular motors induce stimuli that can result in a modification of the physical characteristics of the embedding medium. In azobenzene containing materials for example, a fluidization of the medium has been reported by several groups upon activation of the photo-isomerizing molecule. We discuss here the relations between the fluidization induced by small stimuli in amorphous materials and the glass-transition long standing problem. We focus our attention on the most important characteristic of the glass-transition, the spontaneous appearance of cooperative motions called dynamic heterogeneity that are thought to control the dynamics of the medium. We discuss how motors stimuli create dynamic heterogeneity from a cage-breaking mechanism, the properties of these heterogeneities and their relations with the observed fluidization.
{"title":"Fluidization and dynamic heterogeneity induced by molecular motor’s stimuli in soft matter","authors":"V. Teboul, S. Chaussedent, N. Gaumer","doi":"10.1117/12.2635721","DOIUrl":"https://doi.org/10.1117/12.2635721","url":null,"abstract":"When embedded inside soft matter, molecular motors induce stimuli that can result in a modification of the physical characteristics of the embedding medium. In azobenzene containing materials for example, a fluidization of the medium has been reported by several groups upon activation of the photo-isomerizing molecule. We discuss here the relations between the fluidization induced by small stimuli in amorphous materials and the glass-transition long standing problem. We focus our attention on the most important characteristic of the glass-transition, the spontaneous appearance of cooperative motions called dynamic heterogeneity that are thought to control the dynamics of the medium. We discuss how motors stimuli create dynamic heterogeneity from a cage-breaking mechanism, the properties of these heterogeneities and their relations with the observed fluidization.","PeriodicalId":145218,"journal":{"name":"Organic Photonics + Electronics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130885678","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Metal-dielectric photonic crystals (MDPCs) represent a class of photonic structures which offer unique types of control over the propagation of light. Recent work has demonstrated the ability to form MDPCs using stacked microcavity OLEDs, which enable the generation of complex electroluminescence profiles consisting of multiple emission peaks. Here, we analyze the photonic band formation of idealized MDPCs. We systematically examine the impact of materials parameters on the density of states of the photonic bands and transmission losses through the crystal. We demonstrate the formation and collapse of a Peierls band-gap and the breakdown of the unit cell approach.
{"title":"Parametric investigation of ideal metal-dielectric photonic crystals","authors":"David Allemeier, M. White","doi":"10.1117/12.2632238","DOIUrl":"https://doi.org/10.1117/12.2632238","url":null,"abstract":"Metal-dielectric photonic crystals (MDPCs) represent a class of photonic structures which offer unique types of control over the propagation of light. Recent work has demonstrated the ability to form MDPCs using stacked microcavity OLEDs, which enable the generation of complex electroluminescence profiles consisting of multiple emission peaks. Here, we analyze the photonic band formation of idealized MDPCs. We systematically examine the impact of materials parameters on the density of states of the photonic bands and transmission losses through the crystal. We demonstrate the formation and collapse of a Peierls band-gap and the breakdown of the unit cell approach.","PeriodicalId":145218,"journal":{"name":"Organic Photonics + Electronics","volume":"130 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114090219","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
F. Álvarez-Garrido,, M. Clerc, G. González-Cortés, M. Wilson
Optical coupling in pattern-forming systems brings out the emergence and transition of complex spatiotemporal behaviors. A liquid crystal light valve experiment with translational optical feedback shows the appearance of striped patterns. When the translational coupling length increases, the system exhibits transitions to traveling, spatiotemporal intermittency, and defect turbulence of striped waves. From the first principles, an order parameter equation valid close to the nascent of bistability together with a translationally coupling is derived. The dynamics of the liquid crystal light valve with translational optical feedback and the proposed minimal model system show qualitative agreement.
{"title":"Transition to spatiotemporal intermittency and defect turbulence in a liquid crystal light valve with translational optical feedback","authors":"F. Álvarez-Garrido,, M. Clerc, G. González-Cortés, M. Wilson","doi":"10.1117/12.2632183","DOIUrl":"https://doi.org/10.1117/12.2632183","url":null,"abstract":"Optical coupling in pattern-forming systems brings out the emergence and transition of complex spatiotemporal behaviors. A liquid crystal light valve experiment with translational optical feedback shows the appearance of striped patterns. When the translational coupling length increases, the system exhibits transitions to traveling, spatiotemporal intermittency, and defect turbulence of striped waves. From the first principles, an order parameter equation valid close to the nascent of bistability together with a translationally coupling is derived. The dynamics of the liquid crystal light valve with translational optical feedback and the proposed minimal model system show qualitative agreement.","PeriodicalId":145218,"journal":{"name":"Organic Photonics + Electronics","volume":"146 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115738992","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In recent years, inorganic halide-based non-toxic double perovskite (DP) has emerged as a promising group of materials that are more stable than hybrid lead-based organic and inorganic perovskite materials for green energy applications. In this work, first time we report the synthesis of a new inorganic non-toxic halide-based double perovskite Cs2AlBiCl6 by a simple room-temperature synthesis technique. The structural properties of the synthesized material has been observed by using X-Ray diffraction (XRD). The observed peaks of XRD were found to be in good agreement with the reference data. To envisage the photo physical properties, we have done the photoluminescence (PL) spectroscopy of the synthesized material at low temperature (19 K) and high temperature (300 K). It is clear from the PL spectra that the main peak has been observed around 424 nm corresponding to 2.9 eV energy which also confirms the luminescent behavior of the material. The observed peak in the PL spectra is due to phonon-assisted carrier recombination of the excitons. Also, the PL intensity at low temperature (19K) is high as compared to high temperature (300K) due to a decrease in carrier recombination rate with an increase in temperature. This novel work opens a new path for the synthesis of non-toxic double perovskite materials for photovoltaic and green energy applications.
{"title":"Experimental investigation of structural and photophysical nature of non-toxic Cs2AlBiCl6 double perovskite for photovoltaic applications","authors":"Nivedita Pandey, Neelu Neelu, S. Chakrabarti","doi":"10.1117/12.2632936","DOIUrl":"https://doi.org/10.1117/12.2632936","url":null,"abstract":"In recent years, inorganic halide-based non-toxic double perovskite (DP) has emerged as a promising group of materials that are more stable than hybrid lead-based organic and inorganic perovskite materials for green energy applications. In this work, first time we report the synthesis of a new inorganic non-toxic halide-based double perovskite Cs2AlBiCl6 by a simple room-temperature synthesis technique. The structural properties of the synthesized material has been observed by using X-Ray diffraction (XRD). The observed peaks of XRD were found to be in good agreement with the reference data. To envisage the photo physical properties, we have done the photoluminescence (PL) spectroscopy of the synthesized material at low temperature (19 K) and high temperature (300 K). It is clear from the PL spectra that the main peak has been observed around 424 nm corresponding to 2.9 eV energy which also confirms the luminescent behavior of the material. The observed peak in the PL spectra is due to phonon-assisted carrier recombination of the excitons. Also, the PL intensity at low temperature (19K) is high as compared to high temperature (300K) due to a decrease in carrier recombination rate with an increase in temperature. This novel work opens a new path for the synthesis of non-toxic double perovskite materials for photovoltaic and green energy applications.","PeriodicalId":145218,"journal":{"name":"Organic Photonics + Electronics","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127366454","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Kuzma, T. Vincze, M. Micjan, J. Nevrela, M. Donoval, M. Weis
The charge photogeneration phenomenon in organic semiconducting materials gains great interest due to its application in organic solar cells or photosensitive devices. Here we report the temporal evolution of the photogenerated charge in organic field-effect transistors. Since the charge transfer can be ruled by the drift or diffusion processes, the gate-voltage dependence is used to distinguish the driving force.
{"title":"Dimensionality of photogenerated charges transport in the organic phototransistor","authors":"A. Kuzma, T. Vincze, M. Micjan, J. Nevrela, M. Donoval, M. Weis","doi":"10.1117/12.2640977","DOIUrl":"https://doi.org/10.1117/12.2640977","url":null,"abstract":"The charge photogeneration phenomenon in organic semiconducting materials gains great interest due to its application in organic solar cells or photosensitive devices. Here we report the temporal evolution of the photogenerated charge in organic field-effect transistors. Since the charge transfer can be ruled by the drift or diffusion processes, the gate-voltage dependence is used to distinguish the driving force.","PeriodicalId":145218,"journal":{"name":"Organic Photonics + Electronics","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130474072","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Several morphologies are observed in out-of-equilibrium systems. They can be highly symmetric as stripes, hexagons, or squares, and more complicated such as labyrinthine patterns. These shapes arise in different contexts, ranging from chemistry, biology, and physics. Here we study the emergence of chiral labyrinthine patterns near the winding/unwinding transition of a chiral liquid crystal under geometrical frustration. The patterns emerge due to morphological instabilities of cholesteric fingers of type 1. Experimentally, we show that when heating the cholesteric liquid crystal cell at different rates, the winding/unwinding transition is remarkably different. At low rates, chiral fingers appear and exhibit a serpentine instability along their longitudinal direction. At higher rates, after the chiral fingers nucleate, the splitting of their rounded tips and side-branching along their body is observed. Both mechanisms create labyrinthine patterns. Theoretically, based on an amplitude equation inferred by symmetry arguments, we study the morphological instabilities and characterize them by their interface curvature distribution. We discuss the possible velocity-curvature relationship of the finger rounded tips..
{"title":"Morphological transition of labyrinthine patterns in frustrated chiral nematic liquid crystals","authors":"S. Echeverría-Alar","doi":"10.1117/12.2632197","DOIUrl":"https://doi.org/10.1117/12.2632197","url":null,"abstract":"Several morphologies are observed in out-of-equilibrium systems. They can be highly symmetric as stripes, hexagons, or squares, and more complicated such as labyrinthine patterns. These shapes arise in different contexts, ranging from chemistry, biology, and physics. Here we study the emergence of chiral labyrinthine patterns near the winding/unwinding transition of a chiral liquid crystal under geometrical frustration. The patterns emerge due to morphological instabilities of cholesteric fingers of type 1. Experimentally, we show that when heating the cholesteric liquid crystal cell at different rates, the winding/unwinding transition is remarkably different. At low rates, chiral fingers appear and exhibit a serpentine instability along their longitudinal direction. At higher rates, after the chiral fingers nucleate, the splitting of their rounded tips and side-branching along their body is observed. Both mechanisms create labyrinthine patterns. Theoretically, based on an amplitude equation inferred by symmetry arguments, we study the morphological instabilities and characterize them by their interface curvature distribution. We discuss the possible velocity-curvature relationship of the finger rounded tips..","PeriodicalId":145218,"journal":{"name":"Organic Photonics + Electronics","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116544222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hyong Joon Lee, Seok Yeong Hong, Jin Kyoung Park, Linlin Feng, J. Heo, S. Im
In this study, we implement a laser patterning process on organic-inorganic hybrid perovskite (OIHP) film and perform systematical investigation on the effects of aperture ratios. Through careful aperture ratio control and by using indium tin oxide (ITO) transparent electrode, we can fabricate neutral-colored semitransparent OIHP solar cells. Furthermore, we show that a LiF interlayer between OIHP and C60 electron transport layer (ETL) plays a bifunctional role of interface passivation and current flow rectification. Consequently, we demonstrate a high efficiency of 12.83 % power conversion efficiency (PCE) from a 2.00 cm2 and 9.30 % PCE from 36.00 cm2 area, with 21.74 % average visible transmittance (AVT). In addition, the neutral-colored semitransparent solar cell retains 89.02 % of its initial efficiency after 1,000 hours in dry-air storage without encapsulation.
{"title":"Neutral-colored semitransparent perovskite solar cells by controlling aperture ratios","authors":"Hyong Joon Lee, Seok Yeong Hong, Jin Kyoung Park, Linlin Feng, J. Heo, S. Im","doi":"10.1117/12.2643834","DOIUrl":"https://doi.org/10.1117/12.2643834","url":null,"abstract":"In this study, we implement a laser patterning process on organic-inorganic hybrid perovskite (OIHP) film and perform systematical investigation on the effects of aperture ratios. Through careful aperture ratio control and by using indium tin oxide (ITO) transparent electrode, we can fabricate neutral-colored semitransparent OIHP solar cells. Furthermore, we show that a LiF interlayer between OIHP and C60 electron transport layer (ETL) plays a bifunctional role of interface passivation and current flow rectification. Consequently, we demonstrate a high efficiency of 12.83 % power conversion efficiency (PCE) from a 2.00 cm2 and 9.30 % PCE from 36.00 cm2 area, with 21.74 % average visible transmittance (AVT). In addition, the neutral-colored semitransparent solar cell retains 89.02 % of its initial efficiency after 1,000 hours in dry-air storage without encapsulation.","PeriodicalId":145218,"journal":{"name":"Organic Photonics + Electronics","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115074813","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. Howlader, B. Mishra, N. Khakurel, D. W. Amyx, W. Geerts, G. Gibson, M. Chen
Anti-solvent-free one-step deposition of perovskite thin film shows promising potential for application in slot-die or roll-to-roll mass-fabrication processes of perovskite solar cells. The continuous coverage was confirmed by PV response of devices made using the one-step deposition process. In this work, we have developed a process to deposit MAPb0.75Sn0.25(I0.5Br0.5)3 perovskite thin films without anti-solvent adding MAAc to the ink. By varying the Br content of the perovskite precursor, we were able to tune the bandgap. Fabricated solar cells with the structure ITO/CuI/ MAPb0.75Sn0.25(I0.5Br0.5)3 /C60/BCP/Al with PCE of 4.59% show the path of the fabrication process of antisolvent-free tin-lead-based solar cells
{"title":"Fabricate anti-solvent free tin-lead based perovskite solar cells with MAAc additives","authors":"C. Howlader, B. Mishra, N. Khakurel, D. W. Amyx, W. Geerts, G. Gibson, M. Chen","doi":"10.1117/12.2634371","DOIUrl":"https://doi.org/10.1117/12.2634371","url":null,"abstract":"Anti-solvent-free one-step deposition of perovskite thin film shows promising potential for application in slot-die or roll-to-roll mass-fabrication processes of perovskite solar cells. The continuous coverage was confirmed by PV response of devices made using the one-step deposition process. In this work, we have developed a process to deposit MAPb0.75Sn0.25(I0.5Br0.5)3 perovskite thin films without anti-solvent adding MAAc to the ink. By varying the Br content of the perovskite precursor, we were able to tune the bandgap. Fabricated solar cells with the structure ITO/CuI/ MAPb0.75Sn0.25(I0.5Br0.5)3 /C60/BCP/Al with PCE of 4.59% show the path of the fabrication process of antisolvent-free tin-lead-based solar cells","PeriodicalId":145218,"journal":{"name":"Organic Photonics + Electronics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130839579","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Interfaces between two phases may exhibit enthralling shapes. Optically driven phase transitions are a benchmark that enables spatial control in the order parameter. Dye-doped liquid crystals allow purely optically induced phase transitions. Here we show the temporal evolution of finger-like structures at the nematic-isotropic interface in a photoisomerization experiment in a liquid crystal mixture between E7 and methyl-red dye in twisted planar cells both in the turn-on and turn-o of light scenarios. From the nematic to isotropic liquid transition, triggered by turning on the light, the emergence, growth, and retraction of finger-like structures are observed and characterized. In contrast, the isotropic-to-nematic phase transition when the light turns off transient foam-like and labyrinthine textures are observed. A reduced model based on dopant concentration and the liquid crystal order parameter reproduces all the observed phenomena.
{"title":"Finger forming optically induced phase transition in dye-doped liquid crystal","authors":"G. González-Cortés","doi":"10.1117/12.2594553","DOIUrl":"https://doi.org/10.1117/12.2594553","url":null,"abstract":"Interfaces between two phases may exhibit enthralling shapes. Optically driven phase transitions are a benchmark that enables spatial control in the order parameter. Dye-doped liquid crystals allow purely optically induced phase transitions. Here we show the temporal evolution of finger-like structures at the nematic-isotropic interface in a photoisomerization experiment in a liquid crystal mixture between E7 and methyl-red dye in twisted planar cells both in the turn-on and turn-o of light scenarios. From the nematic to isotropic liquid transition, triggered by turning on the light, the emergence, growth, and retraction of finger-like structures are observed and characterized. In contrast, the isotropic-to-nematic phase transition when the light turns off transient foam-like and labyrinthine textures are observed. A reduced model based on dopant concentration and the liquid crystal order parameter reproduces all the observed phenomena.","PeriodicalId":145218,"journal":{"name":"Organic Photonics + Electronics","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129199766","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Liquid crystals (LCs) are known to have a facile response under external electric and optical fields, which in the past have led to various technological applications such as LC displays or self-focusing flat lenses. In this contribution, we describe how chirality can increase the overall nonlinear optical response of frustrated liquid crystal samples based on the formalism of Green functions. We describe how such an effect can be leveraged to generate low-power spatial optical solitons in diverse sample geometries, and also suggest possible applications that could be derived from this theoretical and numerical work.
{"title":"Chirality-enhanced nonlinear optical response of frustrated liquid crystals","authors":"G. Poy, S. Žumer","doi":"10.1117/12.2593920","DOIUrl":"https://doi.org/10.1117/12.2593920","url":null,"abstract":"Liquid crystals (LCs) are known to have a facile response under external electric and optical fields, which in the past have led to various technological applications such as LC displays or self-focusing flat lenses. In this contribution, we describe how chirality can increase the overall nonlinear optical response of frustrated liquid crystal samples based on the formalism of Green functions. We describe how such an effect can be leveraged to generate low-power spatial optical solitons in diverse sample geometries, and also suggest possible applications that could be derived from this theoretical and numerical work.","PeriodicalId":145218,"journal":{"name":"Organic Photonics + Electronics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122867088","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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