M. Sakamoto, H. T. Nhan, Ryusei Momosaki, Kohei Noda, T. Sasaki, Tadayoshi Kamei, Takeya Sakai, Yukitoshi Hattori, N. Kawatsuki, H. Ono
In this presentation, we propose a scheme for a polarized beam steering system using multiply-cascaded rotating PGs with biaxial anisotropy. Our scheme can steer the polarized beam along both a Lissajous orbit and raster orbit, depending on the synchronization of the rotation frequencies of the PGs. Also, the use of more than two PGs allows us to control the center position of the Lissajous orbit. In addition, by using biaxial anisotropy, the diffraction efficiency and the ellipticity of the steered beam remain almost unchanged during PG rotation. Our beam steering system will apply to LiDAR and laser display.
{"title":"Polarized beam steering by use of multiply-cascaded rotating polarization gratings with biaxial anisotropy","authors":"M. Sakamoto, H. T. Nhan, Ryusei Momosaki, Kohei Noda, T. Sasaki, Tadayoshi Kamei, Takeya Sakai, Yukitoshi Hattori, N. Kawatsuki, H. Ono","doi":"10.1117/12.2593679","DOIUrl":"https://doi.org/10.1117/12.2593679","url":null,"abstract":"In this presentation, we propose a scheme for a polarized beam steering system using multiply-cascaded rotating PGs with biaxial anisotropy. Our scheme can steer the polarized beam along both a Lissajous orbit and raster orbit, depending on the synchronization of the rotation frequencies of the PGs. Also, the use of more than two PGs allows us to control the center position of the Lissajous orbit. In addition, by using biaxial anisotropy, the diffraction efficiency and the ellipticity of the steered beam remain almost unchanged during PG rotation. Our beam steering system will apply to LiDAR and laser display.","PeriodicalId":145218,"journal":{"name":"Organic Photonics + Electronics","volume":"190 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":"122866956","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}
Brandon Vreeland, Comrun Yousefzadeh, Andre VanRynbach, D. Bryant, P. Bos
Pancharatnam Phase Devices (PPDs) are an exciting new area for optical component development. Single layer active devices that provide optical beam steering over a range of several degrees will be discussed. The devices considered here use a comb electrode structure to provide an in-plane electric field to control the optical axis orientation of the liquid crystal director to have the desired spiral pattern of a PPD device. Two basic concepts will be discussed: one that used the in-plane fields to “pin” the only the ends of the spiral pattern; and another that uses sub elements to defines the desired director orientation at several locations in the spiral. The concepts, design details, and modeling results are shown.
{"title":"Single layer, tunable, liquid crystal based Pancharatnam phase devices","authors":"Brandon Vreeland, Comrun Yousefzadeh, Andre VanRynbach, D. Bryant, P. Bos","doi":"10.1117/12.2596462","DOIUrl":"https://doi.org/10.1117/12.2596462","url":null,"abstract":"Pancharatnam Phase Devices (PPDs) are an exciting new area for optical component development. Single layer active devices that provide optical beam steering over a range of several degrees will be discussed. The devices considered here use a comb electrode structure to provide an in-plane electric field to control the optical axis orientation of the liquid crystal director to have the desired spiral pattern of a PPD device. Two basic concepts will be discussed: one that used the in-plane fields to “pin” the only the ends of the spiral pattern; and another that uses sub elements to defines the desired director orientation at several locations in the spiral. The concepts, design details, and modeling results are shown.","PeriodicalId":145218,"journal":{"name":"Organic Photonics + Electronics","volume":"21 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":"126854435","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 the chiral-liquid-crystal (LC*) phase, calamitic molecules are aligned helically; hence, the refractive indices of the materials are altered periodically along the helical axis. The LC* materials have unique optical properties, such as selective reflection, that arise from the periodic structure of the refractive index. Here, we report a simple method for preparing monodispersed microparticles of LC* polymers. Optimizing polymerization conditions, monodispersed LC* polymer microparticles were obtained. In these particles, we could three-dimensionally control the helical-axis orientation of molecules. Based on the helical alignment, each single particle selectively reflected visible light. Because of the monodispersity, the microparticles showed no photonic cross-communication; namely, a clear reflection color without any optical degradation was observed, suggesting that LC* materials have potential for optical application in holographic coatings and omni-directional lasing.
{"title":"Control of helical-axis orientation of chiral liquid crystals in monodispersed polymer particles","authors":"Tomoki Shigeyama, K. Hisano, O. Tsutsumi","doi":"10.1117/12.2594452","DOIUrl":"https://doi.org/10.1117/12.2594452","url":null,"abstract":"In the chiral-liquid-crystal (LC*) phase, calamitic molecules are aligned helically; hence, the refractive indices of the materials are altered periodically along the helical axis. The LC* materials have unique optical properties, such as selective reflection, that arise from the periodic structure of the refractive index. Here, we report a simple method for preparing monodispersed microparticles of LC* polymers. Optimizing polymerization conditions, monodispersed LC* polymer microparticles were obtained. In these particles, we could three-dimensionally control the helical-axis orientation of molecules. Based on the helical alignment, each single particle selectively reflected visible light. Because of the monodispersity, the microparticles showed no photonic cross-communication; namely, a clear reflection color without any optical degradation was observed, suggesting that LC* materials have potential for optical application in holographic coatings and omni-directional lasing.","PeriodicalId":145218,"journal":{"name":"Organic Photonics + Electronics","volume":"19 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":"116641778","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}
Particle-type solutions are generic behaviors in out-of-equilibrium systems. These localized states are characterized by a discrete set of parameters such as position, width, and height. Even these solutions can have topological charges, localized vortices, which enriches the solutions and strengthens their respective stability. These solutions are characterized by exhibiting vorticity surrounded by a homogeneous state without vorticity. Frustrated chiral liquid crystals are a natural habitat for localized vortices, cholesteric bubbles. Here we study the emergence of chiral bubbles in the winding/unwinding transition of a chiral liquid crystal cell with homeotropic anchoring. Experimentally, we show that this winding/unwinding transition is subcritical in nature when one modifies the temperature, which also generates the emergence of spherulites through the contraction of cholesteric labyrinthine patterns. Theoretically, based on an amplitude equation inferred by symmetry arguments, we reveal the emergence of chiral bubbles from a cholesteric labyrinthine patterns.
{"title":"Cholestric bubbles as localized vortices: theory and experiments","authors":"M. Clerc, G. González-Cortés, S. Echeverría-Alar","doi":"10.1117/12.2593418","DOIUrl":"https://doi.org/10.1117/12.2593418","url":null,"abstract":"Particle-type solutions are generic behaviors in out-of-equilibrium systems. These localized states are characterized by a discrete set of parameters such as position, width, and height. Even these solutions can have topological charges, localized vortices, which enriches the solutions and strengthens their respective stability. These solutions are characterized by exhibiting vorticity surrounded by a homogeneous state without vorticity. Frustrated chiral liquid crystals are a natural habitat for localized vortices, cholesteric bubbles. Here we study the emergence of chiral bubbles in the winding/unwinding transition of a chiral liquid crystal cell with homeotropic anchoring. Experimentally, we show that this winding/unwinding transition is subcritical in nature when one modifies the temperature, which also generates the emergence of spherulites through the contraction of cholesteric labyrinthine patterns. Theoretically, based on an amplitude equation inferred by symmetry arguments, we reveal the emergence of chiral bubbles from a cholesteric labyrinthine patterns.","PeriodicalId":145218,"journal":{"name":"Organic Photonics + Electronics","volume":"72 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":"116634459","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}
Md. Asiqur Rahman, Meenu Murali, K. Rodrigues, G. Scalia
The structural characteristics of carbon nanotube (CNT) make them new interesting aligning layers for liquid crystals (LCs). These highly elongated nanoparticles have surface on which LC strongly anchor and with the use of CNTs sheets, continuous films of aligned CNTs can be easily obtained. Despite the fact that CNT sheets are inhomogenous layers since the linear networks of nanotubes cover partially the plane with gaps, of different distance, in the perpendicular direction and that their degree of orientational order can vary locally, with values well below 1, nematic LCs are oriented by the CNTs along their direction of alignment. The alignment of the LC can be clearly affected by the chosen geometry, as studied with symmetric and asymmetric boundary conditions. Certain alignment could be recognized even with only one aligning surface but two are needed for better and more uniform alignment. The orientational order of CNTs was measured by the anisotropic absorption and found being dependent on the processing steps that decrease its value. Higher value of orientational order of the CNTs seem to be relevant for improving the LC alignment even in the case of use of inorganic coatings of CNTs. With simple assemblies, using two substrates or a single one coated even with one CNT sheet, novel LC applications can be realized such as carbon nanotube-based flexible LCDs or pressure sensors.
{"title":"Alignment and disorganization of liquid crystals with carbon nanotubes aligning surfaces for novel applications","authors":"Md. Asiqur Rahman, Meenu Murali, K. Rodrigues, G. Scalia","doi":"10.1117/12.2596466","DOIUrl":"https://doi.org/10.1117/12.2596466","url":null,"abstract":"The structural characteristics of carbon nanotube (CNT) make them new interesting aligning layers for liquid crystals (LCs). These highly elongated nanoparticles have surface on which LC strongly anchor and with the use of CNTs sheets, continuous films of aligned CNTs can be easily obtained. Despite the fact that CNT sheets are inhomogenous layers since the linear networks of nanotubes cover partially the plane with gaps, of different distance, in the perpendicular direction and that their degree of orientational order can vary locally, with values well below 1, nematic LCs are oriented by the CNTs along their direction of alignment. The alignment of the LC can be clearly affected by the chosen geometry, as studied with symmetric and asymmetric boundary conditions. Certain alignment could be recognized even with only one aligning surface but two are needed for better and more uniform alignment. The orientational order of CNTs was measured by the anisotropic absorption and found being dependent on the processing steps that decrease its value. Higher value of orientational order of the CNTs seem to be relevant for improving the LC alignment even in the case of use of inorganic coatings of CNTs. With simple assemblies, using two substrates or a single one coated even with one CNT sheet, novel LC applications can be realized such as carbon nanotube-based flexible LCDs or pressure sensors.","PeriodicalId":145218,"journal":{"name":"Organic Photonics + Electronics","volume":"50 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":"126580005","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}
P. Winget, H. Abroshan, H. Kwak, C. Brown, M. Halls
In this work, we describe an atomistic-scale modeling and simulation scheme to virtually screen both host materials and light emitters used in OLEDs while assessing molecular orientations in film. The work also demonstrates the ability to predict wavelength-dependent refractive indices from atomistic-scale up to achieve this goal. These findings would provide valuable guidelines for the development of new material architectures with superior optical loss properties as well as improved outcoupling efficiencies at the device level.
{"title":"Enhancing OLED outcoupling efficiency via atomistic-scale simulations","authors":"P. Winget, H. Abroshan, H. Kwak, C. Brown, M. Halls","doi":"10.1117/12.2598154","DOIUrl":"https://doi.org/10.1117/12.2598154","url":null,"abstract":"In this work, we describe an atomistic-scale modeling and simulation scheme to virtually screen both host materials and light emitters used in OLEDs while assessing molecular orientations in film. The work also demonstrates the ability to predict wavelength-dependent refractive indices from atomistic-scale up to achieve this goal. These findings would provide valuable guidelines for the development of new material architectures with superior optical loss properties as well as improved outcoupling efficiencies at the device level.","PeriodicalId":145218,"journal":{"name":"Organic Photonics + Electronics","volume":"11808 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129031026","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 the area of environmental monitoring, Volatile Organic Compounds (VOCs) have become a major concern. Specifically, in indoor environments, VOCs have been found to be linked with various health conditions-ranging from benign to lethal. Early detection of VOC gases can play a crucial role in ensuring a safe environment. In this work, we have looked into two different geometrical arrangements of methylammonium lead iodide (MAPbI3) perovskite to study how their selectivity and sensitivity towards an array of VOC gases under different illumination conditions may be affected. For the purpose of a comparative study, we tested the sensitivity of the device using two different photo-resistor designs, namely, (a) capillary-filled microchannels, where microchannels were created on indium tin oxide (ITO) coated plastic substrate, and leveraging the capillary motion force the microchannels were filled with the perovskite precursor solution, and (b) thin-film approach, where perovskite layers were spin coated on substrates with two conductive pads across. Samples of both designs were exposed to four analytes: acetone, ethanol, isopropanol, and methanol. In our previous study on the capillary design, we reported a decrease in photocurrent by about 22% upon exposure to methanol under illuminated conditions. The goal of this comparative study is to identify the viability of the photo-resistor design for fabricating a low-cost and fast-response gas sensor for the purpose of environmental monitoring.
{"title":"Perovskite based gas sensors: thin-film versus capillary-filled microchannel designs","authors":"M. S. Hossain, A. Takshi","doi":"10.1117/12.2593734","DOIUrl":"https://doi.org/10.1117/12.2593734","url":null,"abstract":"In the area of environmental monitoring, Volatile Organic Compounds (VOCs) have become a major concern. Specifically, in indoor environments, VOCs have been found to be linked with various health conditions-ranging from benign to lethal. Early detection of VOC gases can play a crucial role in ensuring a safe environment. In this work, we have looked into two different geometrical arrangements of methylammonium lead iodide (MAPbI3) perovskite to study how their selectivity and sensitivity towards an array of VOC gases under different illumination conditions may be affected. For the purpose of a comparative study, we tested the sensitivity of the device using two different photo-resistor designs, namely, (a) capillary-filled microchannels, where microchannels were created on indium tin oxide (ITO) coated plastic substrate, and leveraging the capillary motion force the microchannels were filled with the perovskite precursor solution, and (b) thin-film approach, where perovskite layers were spin coated on substrates with two conductive pads across. Samples of both designs were exposed to four analytes: acetone, ethanol, isopropanol, and methanol. In our previous study on the capillary design, we reported a decrease in photocurrent by about 22% upon exposure to methanol under illuminated conditions. The goal of this comparative study is to identify the viability of the photo-resistor design for fabricating a low-cost and fast-response gas sensor for the purpose of environmental monitoring.","PeriodicalId":145218,"journal":{"name":"Organic Photonics + Electronics","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123635692","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}
Felix Hermerschmidt, Michael Hengge, V. Schröder, Paul Hänsch, K. Livanov, N. Zamoshchik, E. List‐Kratochvil
The search for alternative transparent electrodes to the commonly used indium tin oxide (ITO) in optoelectronic devices has led to solution-based approaches based on inkjet printing. As an additive manufacturing technique that allows drops to be positioned only where necessary, inkjet printing shows reduced waste of starting material compared to other methods such as spin coating. As a result, functional materials can be both coated and structured without the need for masks or lithographic pre-patterning of the substrate. For this contribution, we utilized a particle-free silver ink to produce a transparent electrode by inkjet printing. After printing, the silver ions were reduced to metallic silver by an argon plasma. The process takes place at low temperatures (ca. 40 – 50°C), making it suitable for use with flexible substrates, which are often temperature-sensitive. The printed silver layers show good electrical conductivity and optical transmittance, with a crystalline grain structure being formed and maintained during the metallization process. This structure forms a self-organized nanometer-size grid, whose structure allows light to pass through. Due to its nano-structured property, the haze of the electrode was investigated using a simple experimental setup based on a light source shining through the electrode and analyzing the size of the projected pattern. Such qualitative assessment can be a useful indication of the quality of the electrode and we provide details on how to replicate this setup. The final electrodes were implemented in solution-processed OLEDs, which showed bright luminance and overall low haze compared to ITO-based reference devices.
{"title":"A guide to qualitative haze measurements demonstrated on inkjet-printed silver electrodes for flexible OLEDs","authors":"Felix Hermerschmidt, Michael Hengge, V. Schröder, Paul Hänsch, K. Livanov, N. Zamoshchik, E. List‐Kratochvil","doi":"10.1117/12.2594486","DOIUrl":"https://doi.org/10.1117/12.2594486","url":null,"abstract":"The search for alternative transparent electrodes to the commonly used indium tin oxide (ITO) in optoelectronic devices has led to solution-based approaches based on inkjet printing. As an additive manufacturing technique that allows drops to be positioned only where necessary, inkjet printing shows reduced waste of starting material compared to other methods such as spin coating. As a result, functional materials can be both coated and structured without the need for masks or lithographic pre-patterning of the substrate. For this contribution, we utilized a particle-free silver ink to produce a transparent electrode by inkjet printing. After printing, the silver ions were reduced to metallic silver by an argon plasma. The process takes place at low temperatures (ca. 40 – 50°C), making it suitable for use with flexible substrates, which are often temperature-sensitive. The printed silver layers show good electrical conductivity and optical transmittance, with a crystalline grain structure being formed and maintained during the metallization process. This structure forms a self-organized nanometer-size grid, whose structure allows light to pass through. Due to its nano-structured property, the haze of the electrode was investigated using a simple experimental setup based on a light source shining through the electrode and analyzing the size of the projected pattern. Such qualitative assessment can be a useful indication of the quality of the electrode and we provide details on how to replicate this setup. The final electrodes were implemented in solution-processed OLEDs, which showed bright luminance and overall low haze compared to ITO-based reference devices.","PeriodicalId":145218,"journal":{"name":"Organic Photonics + Electronics","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132975655","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}
Raj Kishen Radha Krishnan, Shiyi Liu, Drona Dahal, P. Paudel, B. Lüssem
Organic Field Effect Transistors (OFETs), while showing a lot of promise, currently suffer from a number of limitations. Organic doping can help to overcome these limitations. It opens up a number of new possibilities by offering a way to define majority charge carriers, control the charge carrier density, threshold voltage etc. precisely and produce devices with better performance, stability, and reproducibility. The doping techniques explored in OFETs thus far have been in the range of a few wt.%, which has limited the use of doping to contact doping or a thin doped layer at the gate dielectric interface. Furthermore, the high doping concentrations used place serious limitations on the doping efficiency that can be achieved. Here we demonstrate the successful use of low doping in the 100ppm range throughout the bulk of the organic semiconductor layer of an OFET with the use of a rotating shutter.
{"title":"Organic field effect transistors with bulk low doping","authors":"Raj Kishen Radha Krishnan, Shiyi Liu, Drona Dahal, P. Paudel, B. Lüssem","doi":"10.1117/12.2594721","DOIUrl":"https://doi.org/10.1117/12.2594721","url":null,"abstract":"Organic Field Effect Transistors (OFETs), while showing a lot of promise, currently suffer from a number of limitations. Organic doping can help to overcome these limitations. It opens up a number of new possibilities by offering a way to define majority charge carriers, control the charge carrier density, threshold voltage etc. precisely and produce devices with better performance, stability, and reproducibility. The doping techniques explored in OFETs thus far have been in the range of a few wt.%, which has limited the use of doping to contact doping or a thin doped layer at the gate dielectric interface. Furthermore, the high doping concentrations used place serious limitations on the doping efficiency that can be achieved. Here we demonstrate the successful use of low doping in the 100ppm range throughout the bulk of the organic semiconductor layer of an OFET with the use of a rotating shutter.","PeriodicalId":145218,"journal":{"name":"Organic Photonics + Electronics","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121056423","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}
Despite the fast growth of using perovskite materials in solar cells and photo-sensors, there are still many unanswered questions about the processes for their unique electro-optical properties. In this regard, simulation of the material can help for better understanding of the perovskites’ properties. In this study, we have investigated the crystalline structure of methylammonium lead iodide, MAPbI3, perovskite using the density functional theory (DFT). The majority of DFT modeling of perovskite targets the ground state, at 0 K. Analysis at ground state simplifies several quantum mechanical effects and the model results are enlightening. Yet for practical application at ambient temperature, DFT models must include more physical processes which involve making mathematical simplifications and quantum mechanical assumptions to simplify the computations. Here we delved into the practical implication of the move from theory to practical algorithms and tools, identified the range of current computational implications and limitations, the problems of accurately modeling these substances at room temperature, the computational costs, expected results afforded by DFT models for real, practical materials. We have surveyed the required extensions needed to perform DFT on MAPbI3 which necessarily include the temperature modeling, crystal vibrational and frame deformation, phonon action and the novel characteristics of a free MA cation constrained within a Pb-I structure. The developed algorithm for the DFT analysis of perovskite can then be used as a tool for further study of the effect of various factors on the material properties.
{"title":"Density functional theory analysis of perovskite at ambient temperature","authors":"Jon Bebeau, A. Takshi","doi":"10.1117/12.2594937","DOIUrl":"https://doi.org/10.1117/12.2594937","url":null,"abstract":"Despite the fast growth of using perovskite materials in solar cells and photo-sensors, there are still many unanswered questions about the processes for their unique electro-optical properties. In this regard, simulation of the material can help for better understanding of the perovskites’ properties. In this study, we have investigated the crystalline structure of methylammonium lead iodide, MAPbI3, perovskite using the density functional theory (DFT). The majority of DFT modeling of perovskite targets the ground state, at 0 K. Analysis at ground state simplifies several quantum mechanical effects and the model results are enlightening. Yet for practical application at ambient temperature, DFT models must include more physical processes which involve making mathematical simplifications and quantum mechanical assumptions to simplify the computations. Here we delved into the practical implication of the move from theory to practical algorithms and tools, identified the range of current computational implications and limitations, the problems of accurately modeling these substances at room temperature, the computational costs, expected results afforded by DFT models for real, practical materials. We have surveyed the required extensions needed to perform DFT on MAPbI3 which necessarily include the temperature modeling, crystal vibrational and frame deformation, phonon action and the novel characteristics of a free MA cation constrained within a Pb-I structure. The developed algorithm for the DFT analysis of perovskite can then be used as a tool for further study of the effect of various factors on the material properties.","PeriodicalId":145218,"journal":{"name":"Organic Photonics + Electronics","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121326883","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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