S. Forrest, P. Burrows, Z. Shen, V. Bulović, D. McCarty, M. E. Thompson
Electroluminescence (EL) from vacuum deposited organic molecular heterojunction (HJ) devices can potentially yield red, green and blue light at levels of brightnesses and efficiencies adequate for viable flat panel displays1. However, to date, there has been little detailed analysis of the origin of EL and the current conduction mechanisms in these novel devices. The spatial distribution of EL in HJ devices using tris-(8-hydroxyquinoline) aluminum (Alq3) as the light emitting layer has been measured and shown to occur within a few hundred Ångstroms of the organic HJ.2 This was assigned to excitons created at the organic HJ subsequently diffusing into the bulk organic layer before radiatively recombining. Charge injection mechanisms in such structures, however, were not elucidated. In polymeric OLEDs, tunneling3 into the conduction bands of the organic material has been invoked to explain the observed current-voltage (I-V) and EL characteristics. However, given the low carrier mobilities characteristic of many organic materials and the difficulties in measuring and interpreting band offset data, the validity of simple band structure and tunneling models remains unclear.
{"title":"Current Conduction and Electroluminescence Mechanisms in Molecular Organic Light Emitting Devices.","authors":"S. Forrest, P. Burrows, Z. Shen, V. Bulović, D. McCarty, M. E. Thompson","doi":"10.1364/otfa.1995.tua.2","DOIUrl":"https://doi.org/10.1364/otfa.1995.tua.2","url":null,"abstract":"Electroluminescence (EL) from vacuum deposited organic molecular heterojunction (HJ) devices can potentially yield red, green and blue light at levels of brightnesses and efficiencies adequate for viable flat panel displays1. However, to date, there has been little detailed analysis of the origin of EL and the current conduction mechanisms in these novel devices. The spatial distribution of EL in HJ devices using tris-(8-hydroxyquinoline) aluminum (Alq3) as the light emitting layer has been measured and shown to occur within a few hundred Ångstroms of the organic HJ.2 This was assigned to excitons created at the organic HJ subsequently diffusing into the bulk organic layer before radiatively recombining. Charge injection mechanisms in such structures, however, were not elucidated. In polymeric OLEDs, tunneling3 into the conduction bands of the organic material has been invoked to explain the observed current-voltage (I-V) and EL characteristics. However, given the low carrier mobilities characteristic of many organic materials and the difficulties in measuring and interpreting band offset data, the validity of simple band structure and tunneling models remains unclear.","PeriodicalId":246676,"journal":{"name":"Organic Thin Films for Photonic Applications","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128125107","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}
Because of advances in optical communications and information storage, researchers have sought materials for devices operating at the boundaries between the electronic and optical realms. Second-order nonlinear optical (NLO) materials, particularly organic polymers, have received attention because of their facility for constructing waveguiding thin films that are capable of frequency doubling or electrooptic modulation in integrated optical circuitry.
{"title":"New Side-Chain Polymers for Second-Order Nonlinear Optics","authors":"Douglas R. Robello, J. Schildkraut, C. S. Willand","doi":"10.1364/otfa.1993.fb.1","DOIUrl":"https://doi.org/10.1364/otfa.1993.fb.1","url":null,"abstract":"Because of advances in optical communications and information storage, researchers have sought materials for devices operating at the boundaries between the electronic and optical realms. Second-order nonlinear optical (NLO) materials, particularly organic polymers, have received attention because of their facility for constructing waveguiding thin films that are capable of frequency doubling or electrooptic modulation in integrated optical circuitry.","PeriodicalId":246676,"journal":{"name":"Organic Thin Films for Photonic Applications","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128753637","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}
Electroluminescence from small organic molecules has been known for some time. Thirty years ago, Helfrich and Schneider reported blue-violet electroluminescence in anthracene with an external quantum efficiency as high as 8%.1 This quantum efficiency is much better than that for the best polymer-based light-emitting diode (LED) reported to date.2 In spite of the superior quantum efficiency of molecular-based electroluminescent devices, no major progress was achieved until fairly recently when Tang and VanSlyke reported the first low-voltage organic LED with an external quantum efficiency of 1% (number of photons per electron).3 The emitting layer in this device consists of a thin layer of the metal complex, tris (8-hydroxyquinolinato) aluminum (AlQ3). Later, Littman and Martie showed an enhancement in the electroluminescence quantum efficiency of AlQ3 by doping it with the highly fluorescent laser dyes, Coumarin 540, Coumarin 343, and DCM.4 The paper focuses on a new class of organic composites consisting of highly fluorescent guest molecules dispersed in AlQ3. The electronic and optical properties of organic nanostructures based on these materials are studied, as functions of the luminescent center concentration, via optical and fluorescence spectroscopies. Photoluminescence quantum yields are measured and used to probe the efficiency of energy transfer between host and guest molecules.
{"title":"Preparation, Optical Spectroscopy, and Fluorescence of Molecular Organic Composites for Light-Emitting Diodes","authors":"H. W. Sarkas, C. D. Merritt, Z. Kafafi","doi":"10.1364/otfa.1995.md.35","DOIUrl":"https://doi.org/10.1364/otfa.1995.md.35","url":null,"abstract":"Electroluminescence from small organic molecules has been known for some time. Thirty years ago, Helfrich and Schneider reported blue-violet electroluminescence in anthracene with an external quantum efficiency as high as 8%.1 This quantum efficiency is much better than that for the best polymer-based light-emitting diode (LED) reported to date.2 In spite of the superior quantum efficiency of molecular-based electroluminescent devices, no major progress was achieved until fairly recently when Tang and VanSlyke reported the first low-voltage organic LED with an external quantum efficiency of 1% (number of photons per electron).3 The emitting layer in this device consists of a thin layer of the metal complex, tris (8-hydroxyquinolinato) aluminum (AlQ3). Later, Littman and Martie showed an enhancement in the electroluminescence quantum efficiency of AlQ3 by doping it with the highly fluorescent laser dyes, Coumarin 540, Coumarin 343, and DCM.4 The paper focuses on a new class of organic composites consisting of highly fluorescent guest molecules dispersed in AlQ3. The electronic and optical properties of organic nanostructures based on these materials are studied, as functions of the luminescent center concentration, via optical and fluorescence spectroscopies. Photoluminescence quantum yields are measured and used to probe the efficiency of energy transfer between host and guest molecules.","PeriodicalId":246676,"journal":{"name":"Organic Thin Films for Photonic Applications","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124431880","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}
S. Bauer, S. Bauer-Gogonea, Ş. Yilmaz, C. Dinger, W. Wirges, R. Gerhard-Multhaupt, F. Michelotti, E. Toussaere, R. Levenson, J. Liang, J. Zyss
Cross-linking of nonlinear optical polymers during the poling process is an interesting way to increase the thermal stability of the dipole orientation [1]. For the optimization of the poling process in cross-linking polymers, experimental techniques for the in- situ characterization of the polar order are highly desirable. Recently, Aramaki et al. [2] introduced in-situ electro-optical measurements by the ellipsometric method in order to follow the cross-linking process by optical means. They also established a direct connection between dielectric and in-situ electro-optical measurements [3]. Here we report a comprehensive study of the cross-linking process of Red Acid Magly by means of dielectric, in-situ electro-optical and pyroelectrical measurements. In addition we extend the model in [3] for the interpretation of in-situ electro-optical measurements and their connection to the dielectric properties.
{"title":"Pyroelectric, dielectric and electro-optical investigation of cross-linking in Red Acid Magly","authors":"S. Bauer, S. Bauer-Gogonea, Ş. Yilmaz, C. Dinger, W. Wirges, R. Gerhard-Multhaupt, F. Michelotti, E. Toussaere, R. Levenson, J. Liang, J. Zyss","doi":"10.1364/otfa.1995.md.17","DOIUrl":"https://doi.org/10.1364/otfa.1995.md.17","url":null,"abstract":"Cross-linking of nonlinear optical polymers during the poling process is an interesting way to increase the thermal stability of the dipole orientation [1]. For the optimization of the poling process in cross-linking polymers, experimental techniques for the in- situ characterization of the polar order are highly desirable. Recently, Aramaki et al. [2] introduced in-situ electro-optical measurements by the ellipsometric method in order to follow the cross-linking process by optical means. They also established a direct connection between dielectric and in-situ electro-optical measurements [3]. Here we report a comprehensive study of the cross-linking process of Red Acid Magly by means of dielectric, in-situ electro-optical and pyroelectrical measurements. In addition we extend the model in [3] for the interpretation of in-situ electro-optical measurements and their connection to the dielectric properties.","PeriodicalId":246676,"journal":{"name":"Organic Thin Films for Photonic Applications","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125129748","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}
To improve the stabilities and processabilities, blend or graft polymerization of nonlinear optical organic materials with polymers has been intensively studied by many researchers (1-3). However, it was pointed out that there remain problems in the durability (4). To the contrary, the main-chain type nonlinear optical polymers are expected to be durable and good nonlinear optical materials for various applications, because these materials have been developed to be high performance materials.
{"title":"Optical Second Harmonic Generations of the Thermotropic Liquid Crystalline Main-Chain Polymer (Aromatic Polyesters)","authors":"T. Asada","doi":"10.1364/otfa.1995.thd.3","DOIUrl":"https://doi.org/10.1364/otfa.1995.thd.3","url":null,"abstract":"To improve the stabilities and processabilities, blend or graft polymerization of nonlinear optical organic materials with polymers has been intensively studied by many researchers (1-3). However, it was pointed out that there remain problems in the durability (4). To the contrary, the main-chain type nonlinear optical polymers are expected to be durable and good nonlinear optical materials for various applications, because these materials have been developed to be high performance materials.","PeriodicalId":246676,"journal":{"name":"Organic Thin Films for Photonic Applications","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125828561","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}
S. Bauer, W. Ren, Ş. Yilmaz, W. Wirges, R. Gerhard-Multhaupt
Second-order nonlinear optical polymers must be poled in order to achieve the required non-centrosymmetry. Periodically poled materials are required for phase-matched operation of polarization converters1 and parametric devices2. For second-harmonic generation with modes of different order1, three-dimensionally (3-D) poled patterns are needed to optimize the overlap integral, as suggested by Akhmediev and Novak3. As the poled polymer is in a metastable state, the partially aligned dipoles relax, thus limiting the lifetime of the poled polymer. Easy-to-use experimental methods, which allow for the investigation of dipole relaxation as well as periodical and 3-D dipole patterns, are highly desirable. It will be shown that the recently developed techniques of Pyroelectrical Thermal Analysis (PTA), Scanning Pyroelectrical Microscopy (SPM), and Pyroelectrical Depth Profiling (PDP), respectively, are almost ideal solutions for these tasks.
{"title":"Pyroelectrical Thermal Analysis, Pyroelectrical Microscopy, and Pyroelectrical Depth Profiling of Poled Polymer Films","authors":"S. Bauer, W. Ren, Ş. Yilmaz, W. Wirges, R. Gerhard-Multhaupt","doi":"10.1364/otfa.1993.fb.4","DOIUrl":"https://doi.org/10.1364/otfa.1993.fb.4","url":null,"abstract":"Second-order nonlinear optical polymers must be poled in order to achieve the required non-centrosymmetry. Periodically poled materials are required for phase-matched operation of polarization converters1 and parametric devices2. For second-harmonic generation with modes of different order1, three-dimensionally (3-D) poled patterns are needed to optimize the overlap integral, as suggested by Akhmediev and Novak3. As the poled polymer is in a metastable state, the partially aligned dipoles relax, thus limiting the lifetime of the poled polymer. Easy-to-use experimental methods, which allow for the investigation of dipole relaxation as well as periodical and 3-D dipole patterns, are highly desirable. It will be shown that the recently developed techniques of Pyroelectrical Thermal Analysis (PTA), Scanning Pyroelectrical Microscopy (SPM), and Pyroelectrical Depth Profiling (PDP), respectively, are almost ideal solutions for these tasks.","PeriodicalId":246676,"journal":{"name":"Organic Thin Films for Photonic Applications","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126045275","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}
Liming Wang, T. Wada, Tomoyuki Yuba, M. Kakimoto, Y. Imai, H. Sasabe
Poly(p-phenylene benzobisthiazole) (PBT) has received a strong attention as a nonlinear optical (NLO) material because of its large, ultrafast NLO response1 and inherently superior physical and chemical properties2. However, the material is difficult to process into thin film with good optical quality, which hindered the detailed and accurate NLO studies. In order to improve optical quality, the PBT Langmuir-Blodgett (LB) films were fabricated via a novel precursor route. The PBT LB films show not only improved optical quality but also highly in-plane oriented molecular packing. Because the π-electrons are delocalized along the polymer chain direction, the highly oriented packing of the polymer chains results in linear and NLO anisotropy properties. Therefore, in-plane anisotropy measurement of optical third-harmonic generation (THG) is one of the powerful tools to elucidate the packing arrangement in LB films of one-dimensional conjugated system.
{"title":"Nonlinear Optical Anisotropy of Highly Oriented Poly(p-Phenylene Benzobisthiazole)Langmuir-Blodgett Films","authors":"Liming Wang, T. Wada, Tomoyuki Yuba, M. Kakimoto, Y. Imai, H. Sasabe","doi":"10.1364/otfa.1995.md.26","DOIUrl":"https://doi.org/10.1364/otfa.1995.md.26","url":null,"abstract":"Poly(p-phenylene benzobisthiazole) (PBT) has received a strong attention as a nonlinear optical (NLO) material because of its large, ultrafast NLO response1 and inherently superior physical and chemical properties2. However, the material is difficult to process into thin film with good optical quality, which hindered the detailed and accurate NLO studies. In order to improve optical quality, the PBT Langmuir-Blodgett (LB) films were fabricated via a novel precursor route. The PBT LB films show not only improved optical quality but also highly in-plane oriented molecular packing. Because the π-electrons are delocalized along the polymer chain direction, the highly oriented packing of the polymer chains results in linear and NLO anisotropy properties. Therefore, in-plane anisotropy measurement of optical third-harmonic generation (THG) is one of the powerful tools to elucidate the packing arrangement in LB films of one-dimensional conjugated system.","PeriodicalId":246676,"journal":{"name":"Organic Thin Films for Photonic Applications","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127233754","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}
Amorphous high glass transition polymer films containing electron-donor electron-acceptor substituted azobenzene groups can be used as materials for reversible optical storage1. A polarized argon laser beam is used for "writing" while a low power HeNe laser can "read" the resulting oriented regions, and irradiation with circularly polarized light destroys the order, effectively "erasing" the signal. As orientation is induced by a series of trans-cis-trans isomerizations of the azo groups, writing speeds and efficiencies depend on the rates of these isomerizations. Films of a series of azo polymers used for reversible optical storage were prepared and irradiated in order to study the thermal cis-trans isomerization rates.
{"title":"Thermal Cis-Trans Isomerization Rates Of Azobenzenes Bound In Acrylate Polymers","authors":"C. Barrett, A. Natansohn, P. Rochon, S. Xie","doi":"10.1364/otfa.1993.wd.26","DOIUrl":"https://doi.org/10.1364/otfa.1993.wd.26","url":null,"abstract":"Amorphous high glass transition polymer films containing electron-donor electron-acceptor substituted azobenzene groups can be used as materials for reversible optical storage1. A polarized argon laser beam is used for \"writing\" while a low power HeNe laser can \"read\" the resulting oriented regions, and irradiation with circularly polarized light destroys the order, effectively \"erasing\" the signal. As orientation is induced by a series of trans-cis-trans isomerizations of the azo groups, writing speeds and efficiencies depend on the rates of these isomerizations. Films of a series of azo polymers used for reversible optical storage were prepared and irradiated in order to study the thermal cis-trans isomerization rates.","PeriodicalId":246676,"journal":{"name":"Organic Thin Films for Photonic Applications","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122939057","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}
Surface second harmonic generation is used to study surface reactions during photopolymerization of vinyl monomers on metal surfaces. Photopolymerization shows promise in making defect-free insulating and abrasion resistant coatings, and in the fabrication of microelectronic devices1. Although researchers have studied the gas phase reaction in some detail, little is known about the surface reactions2. Also, the effects of various physical parameters such as monomer pressure, light intensity, and the nature of metal and the monomer on the physical properties of polymer films are not known.
{"title":"Studies of Photopolymerization at Metal Surfaces","authors":"Suchitra Subrahmanyan, Fang Chen, H. Lackritz","doi":"10.1364/otfa.1995.md.14","DOIUrl":"https://doi.org/10.1364/otfa.1995.md.14","url":null,"abstract":"Surface second harmonic generation is used to study surface reactions during photopolymerization of vinyl monomers on metal surfaces. Photopolymerization shows promise in making defect-free insulating and abrasion resistant coatings, and in the fabrication of microelectronic devices1. Although researchers have studied the gas phase reaction in some detail, little is known about the surface reactions2. Also, the effects of various physical parameters such as monomer pressure, light intensity, and the nature of metal and the monomer on the physical properties of polymer films are not known.","PeriodicalId":246676,"journal":{"name":"Organic Thin Films for Photonic Applications","volume":"105 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127156797","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}
The birefringence-free copolymer was prepared by randomly copolymerizing positive and negative birefringent monomers. The birefringence-free copolymer showed excellent transparency and no microscopic heterogeneous structures were observed. As a novel application of the birefringence-free copolymer, we propose the polarization preserving polymer optical fiber (POF).
{"title":"Transparent Birefringence-free Copolymer and its Application","authors":"Shuichi Iwata, H. Tsukahara, E. Nihei, Y. Koike","doi":"10.1364/otfa.1995.mb.3","DOIUrl":"https://doi.org/10.1364/otfa.1995.mb.3","url":null,"abstract":"The birefringence-free copolymer was prepared by randomly copolymerizing positive and negative birefringent monomers. The birefringence-free copolymer showed excellent transparency and no microscopic heterogeneous structures were observed. As a novel application of the birefringence-free copolymer, we propose the polarization preserving polymer optical fiber (POF).","PeriodicalId":246676,"journal":{"name":"Organic Thin Films for Photonic Applications","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131336171","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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