Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 29
Filtrar
1.
Retina ; 42(1): 19-26, 2022 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-34267116

RESUMO

PURPOSE: The aim of the study is to compare the efficacy, safety, and globe akinesia between retrobulbar anesthesia, sub-Tenon anesthesia, and medial canthus episcleral anesthesia for 25-gauge posterior vitrectomy. METHODS: A total of 340 25-gauge vitrectomy data sheets were retrospectively collected between November 2017 and June 2019. Ninety patients were included in the study. These patients were matched by sex and age to receive retrobulbar anesthesia (group 1, n = 30), sub-Tenon anesthesia (group 2, n = 30), and medial canthus episcleral anesthesia (group 3, n = 30). Globe akinesia was recorded after the injection of anesthetic at 2, 5, and 10 minute time intervals. Patients were asked to rate the pain during administration of anesthesia, during surgery, and postoperatively using the visual analog pain scale. RESULTS: For a perfect block, at 10 minutes, retrobulbar outperformed both sub-Tenon and medial canthus episcleral anesthesia which seemed quite similar. During administration, the three techniques did not show statistically different effects on pain. Regarding perioperative pain, retrobulbar outperformed medial canthus episcleral anesthesia. CONCLUSION: All three techniques allowed for safe surgery. Retrobulbar obtained the best results, although sub-Tenon proved to be a valid alternative. Medial canthus episcleral anesthesia obtained mostly good and fair blocks and acceptable pain levels during surgery. Further studies should investigate whether optimal anesthetic efficacy can be obtained with sub-Tenon and medial canthus episcleral techniques when higher volumes are used.


Assuntos
Anestesia Local/métodos , Anestésicos Locais/administração & dosagem , Dor/tratamento farmacológico , Vitrectomia , Idoso , Idoso de 80 Anos ou mais , Relação Dose-Resposta a Droga , Feminino , Seguimentos , Humanos , Injeções , Masculino , Pessoa de Meia-Idade , Dor/diagnóstico , Medição da Dor/métodos , Estudos Retrospectivos , Esclera , Cápsula de Tenon
2.
Analyst ; 139(22): 6010-5, 2014 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-25270688

RESUMO

A novel fully spray coating-based method of the preparation of all-solid-state ion-selective electrodes of simplified construction is proposed. This method is an alternative for screen-printed electrodes used sometimes in potentiometric applications. The benefits of the herein-proposed approach include fully automatic sensor preparation and minimized use of chemicals allowing for the production of low-cost sensors that can be applied as disposables. A layer of spray-coated carbon nanotubes on an inert support was used both as an electrical lead and as a transducer, to simplify sensor layout and to avoid the possible problems of changing in-time composition of this layer, as previously observed in the case of screen-printed supporting electrodes in potentiometric applications. The ion-selective poly(vinyl chloride)-based membrane and the insulator layer were also spray-coated. The obtained sensors, as the model system potassium-selective sensors were prepared and characterized with analytical parameters well comparable with that of conventional, all-solid-state, ion-selective electrodes. In addition, the applicability of the herein-proposed approach to prepare other ion-selective electrodes was tested on examples of H(+) and Cl(-) sensors.

3.
Nanotechnology ; 25(5): 055208, 2014 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-24407105

RESUMO

We report the fabrication of carbon nanotube (CNT) based gas sensors functionalized with different metallic nanoparticles (NPs) (Au, Pd, Ag) with exceptionally high responses towards four test gases (NH3, CO2, CO and ethanol). The CNT networks were fabricated through a low cost spray deposition process while the NPs were deposited by a thermal evaporation process. CNT based gas sensors functionalized with Au with a nominal thickness of 1.0 nm showed superior response towards NH3, CO and ethanol. The sensors' normalized responses reached 92%, 22% and 32% with concentrations of 100 ppm, 50 ppm and 100 ppm for NH3, CO and ethanol respectively. CNT based gas sensors functionalized with Pd with a nominal thickness of 1.5 nm showed the best performance with CO2. The normalized response reached 3%, 6%, 12% and 17% with concentrations of 500 ppm, 1000 ppm, 2500 ppm and 5000 ppm of CO2 respectively. We also investigated the morphological and optical changes that occur to the NPs upon thermal treatment. Functionalization of CNT films deposited on glass with Au and Ag showed surface plasmon resonance effects that are dependent on the nominal thickness of the functionalization layer.

4.
J Oral Maxillofac Surg ; 72(3): 645.e1-6, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24528568

RESUMO

Traumatic intraocular foreign bodies are a particular subset of open globe injuries usually caused by metal processing, blasts, or yard work. This case report presents a retained intraocular screw as a complication of mesh positioning during lateral orbit reconstruction after resection of a left spheno-orbital infiltrating meningioma.


Assuntos
Parafusos Ósseos/efeitos adversos , Corpos Estranhos no Olho/cirurgia , Órbita/cirurgia , Procedimentos de Cirurgia Plástica/instrumentação , Corpos Estranhos no Olho/diagnóstico por imagem , Corpos Estranhos no Olho/etiologia , Feminino , Humanos , Meningioma/cirurgia , Pessoa de Meia-Idade , Neoplasias Orbitárias/cirurgia , Complicações Pós-Operatórias/diagnóstico por imagem , Complicações Pós-Operatórias/cirurgia , Radiografia , Procedimentos de Cirurgia Plástica/efeitos adversos , Telas Cirúrgicas/efeitos adversos
5.
Eur J Ophthalmol ; 32(6): 3667-3673, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-35132906

RESUMO

BACKGROUND: Intravitreal injection (IVI) is a standard procedure performed in ophthalmology to treat several conditions, and is performed in different settings across countries. The Italian guidelines recommend this intervention is performed in an operating room to minimize the risk of infections, while in other countries, including Canada, USA and the UK, IVIs are performed in the ophthalmologist's office. The 2020 COVID-19 outbreak caused a dramatic modification in outpatient care. Consequently, non-urgent surgical activities, like IVIs, were subjected to a drastic reduction. METHODS: We conducted observational study which investigated the outcomes of IVIs performed in an ophthalmologist's office using a mobile laminar flow unit, the Operio mobile (Toul Meditech, Operio®) versus an operating room setting. RESULTS: Use of the Operio mobile allowed the safety performance of 3838 IVIs during COVID-19 and significantly reduced the waiting time of the first visit. This results in a faster intervention without affecting the technical IVI procedure that remained unchanged comparing the two settings. Specifically, we observed a 26% reduction in operation costs for each IVI performed in the office, which can be translated to a higher impact when considering the total number of IVIs performed over one year. CONCLUSION: The use of the Operio mobile in an ophthalmologist's office provides flexibility to perform IVIs, assuring patient safety, reducing healthcare personnel employment times, and the waiting lists for the patients, increasing the number of surgeries and improving the cost-effectiveness of the procedure.


Assuntos
COVID-19 , Oftalmologia , COVID-19/epidemiologia , Surtos de Doenças , Humanos , Injeções Intravítreas , Salas Cirúrgicas
6.
Opt Express ; 19 Suppl 1: A7-19, 2011 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-21263715

RESUMO

Organic light-emitting diodes (OLEDs) usually exhibit a low light outcoupling efficiency because a large fraction of power is lost to surface plasmons (SPs) and waveguide modes. In this paper it is demonstrated that periodic grating structures with almost µm-scale can be used to extract SPs as well as waveguide modes and therefore enhance the outcoupling efficiency in light-emitting thin film structures. The gratings are fabricated by nanoimprint lithography using a commercially available diffraction grating as a mold which is pressed into a polymer resist. The outcoupling of SPs and waveguide modes is detected in fluorescent organic films adjacent to a thin metal layer in angular dependent photoluminescence measurements. Scattering up to 5th-order is observed and the extracted modes are identified by comparison to the SP and waveguide dispersion obtained from optical simulations. In order to demonstrate the low-cost, high quality and large area applicability of grating structures in optoelectronic devices, we also present SP extraction using a grating structure fabricated by a common DVD stamp.


Assuntos
Nanotecnologia/métodos , Ressonância de Plasmônio de Superfície/métodos , Algoritmos , Eletrônica , Corantes Fluorescentes/química , Luz , Luminescência , Microscopia de Força Atômica/métodos , Modelos Estatísticos , Óptica e Fotônica , Compostos Orgânicos/química , Espalhamento de Radiação
7.
Animals (Basel) ; 11(3)2021 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-33668903

RESUMO

There is a growing demand by the modern consumer for meat containing less fat and lower levels of saturated fatty acids, which are considered to increase the risk of coronary heart disease. In southern Italy, the Gentile di Puglia breed is one of the most common on farms, and the light lambs are often consumed. The study evaluates the effect of a diet containing extruded linseed (Linum usitatissimum) on growth performances, carcass traits, and meat quality in Gentile di Puglia light lambs. Thirty-six male lambs are weaned at about 20 days of age, and divided into three groups-each group is either fed a control diet (C), a diet containing 3% extruded linseed (L), or a diet containing 3% extruded linseed and 0.6% oregano (Origanum vulgare) (L + O). The lambs' growth performances and the slaughtering and dissection data did not differ between groups. Dietary treatments have no significant effect on the quality and chemical composition of Longissimus lumborum (Ll). The mount of linoleic acid in Ll meat is significantly higher in the L group, and this positively affected the total content of n-3 Polyunsaturated Fatty Acid, as well as the n-6/n-3 ratio. The good results obtained concerning the sensory traits meet the requirements of the market's consumer.

8.
Eur J Ophthalmol ; 31(6): 2901-2909, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33319590

RESUMO

PURPOSE: To describe a strategy to reduce Covid-19 spread among healthcare workers and provide ophthalmologists with recommendations useful for a possible second wave of Covid-19 in Autumn. METHODS: Epidemiological surveillance at the Cà Foncello Hospital (Veneto, Italy) since 24 February 2020 to 24 April 2020 when the municipality of Treviso was hit by the Covid-19 outbreak. The number of naso-pharigeal (NP) swabs performed was 7010. RESULTS: The number of infected among healthcare workers was 209/ 3924 (5.32%): medical doctors: 28 cases / 498 (5.6%). None among ophthalmologists; specialized nurses: 86/1294 (6.4%) None in the ophthalmic unit; intermediate care technicians: 68/463 (14.7%). The 46% of the positive tested were asymptomatic. We share key suggested actions for the reorganization in ophthalmological services: be part of a global epidemiological local strategy of containment (Testing, Tracing, Treating); protect your department: Keep on screening patients by telephone interview before entering the hospital; promote continuous and appropriate use of PPE both for doctors and for patients; make any effort to obtain a continuous flow of patients in every line of the ophthalmic service; treat appropriately any single patient with vision threatening condition; avoid unnecessary or futile testings and examinations. CONCLUSION: The Treviso model shows that it is possible and safe to keep on performing high risk hospital activities like ophthalmology, even in the epicenter of covid outbreak, if adequate actions are performed. We discuss about the value of NP swabs and serological tests as a strategy in case of a second wave of infections.


Assuntos
COVID-19 , Oftalmologistas , Surtos de Doenças , Pessoal de Saúde , Hospitais , Humanos , Itália/epidemiologia , SARS-CoV-2
9.
Sensors (Basel) ; 10(3): 2262-73, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-22294926

RESUMO

We have fabricated organic field-effect transistors (OFETs) with regioregular poly(3-hexylthiophene) (P3HT) operable at low-voltages in liquid solutions, suitable for in vitro biosensing applications. Measurements in electrolytes have shown that the performance of the transistors did not deteriorate and they can be directly used as ion-sensitive transducers. Furthermore, more complex media have been tested, with the perspective of cell analysis. Degradation effects acting on the device operating in liquid could be partly compensated by adopting an alternate current measuring mode.


Assuntos
Técnicas Biossensoriais/instrumentação , Tiofenos/química , Transistores Eletrônicos , Cátions/análise , Eletrólitos , Concentração de Íons de Hidrogênio , Temperatura
10.
IEEE Trans Image Process ; 18(8): 1830-43, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19447707

RESUMO

In this paper, we present a novel multiscale texture model and a related algorithm for the unsupervised segmentation of color images. Elementary textures are characterized by their spatial interactions with neighboring regions along selected directions. Such interactions are modeled, in turn, by means of a set of Markov chains, one for each direction, whose parameters are collected in a feature vector that synthetically describes the texture. Based on the feature vectors, the texture are then recursively merged, giving rise to larger and more complex textures, which appear at different scales of observation: accordingly, the model is named Hierarchical Multiple Markov Chain (H-MMC). The Texture Fragmentation and Reconstruction (TFR) algorithm, addresses the unsupervised segmentation problem based on the H-MMC model. The "fragmentation" step allows one to find the elementary textures of the model, while the "reconstruction" step defines the hierarchical image segmentation based on a probabilistic measure (texture score) which takes into account both region scale and inter-region interactions. The performance of the proposed method was assessed through the Prague segmentation benchmark, based on mosaics of real natural textures, and also tested on real-world natural and remote sensing images.


Assuntos
Algoritmos , Processamento de Imagem Assistida por Computador/métodos , Cadeias de Markov , Reconhecimento Automatizado de Padrão/métodos , Análise por Conglomerados , Modelos Estatísticos
11.
J Ocul Pharmacol Ther ; 34(3): 298-308, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29148864

RESUMO

Intravitreal antivascular endothelial growth factor drugs represent the current standard of care for neovascular age-related macular degeneration (nAMD). Individualized treatment regimens aim at obtaining the same visual benefits of monthly injections with a reduced number of injections and follow-up visits, and, consequently, of treatment burden. The target of these strategies is to timely recognize lesion recurrence, even before visual deterioration. Early detection of lesion activity is critical to ensure that clinical outcomes are not compromised by inappropriate delays in treatment, but questions remain on how to effectively monitor the choroidal neovascularization (CNV) activity. To assess the persistence/recurrence of lesion activity in patients undergoing treatment for nAMD, an expert panel developed a decision algorithm based on the morphological features of CNV. After evaluating all current retinal imaging techniques, the panel identified optical coherent tomography as the most reliable tool to ascertain lesion activity when funduscopy is not obvious.


Assuntos
Inibidores da Angiogênese/uso terapêutico , Neovascularização de Coroide/tratamento farmacológico , Degeneração Macular/tratamento farmacológico , Fatores Etários , Algoritmos , Inibidores da Angiogênese/administração & dosagem , Neovascularização de Coroide/metabolismo , Consenso , Humanos , Injeções Intravítreas , Degeneração Macular/metabolismo
12.
Eur J Ophthalmol ; 28(6): 625-632, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29577739

RESUMO

BACKGROUND:: One of the directions of modern ophthalmology is toward an odontoiatric model, and new settings of eye care are becoming the standard of care: one day surgery and also office-based therapies. METHODS:: Retrospective analysis of three tertiary-care centers in Italy and analysis of the literature. RESULTS:: We provide readers with state-of-the-art measures of prophylaxis in ophthalmic surgery. DISCUSSION AND CONCLUSION:: Role of antibiotics is criticized in the light of stewardship antimicrobial paradigm.


Assuntos
Antibacterianos/uso terapêutico , Endoftalmite/prevenção & controle , Oftalmologia/métodos , Antibioticoprofilaxia/métodos , Gestão de Antimicrobianos/normas , Humanos , Itália , Estudos Retrospectivos , Centros de Atenção Terciária
13.
Eur J Ophthalmol ; 26(2): e27-9, 2016 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-26559933

RESUMO

PURPOSE: To report an atypical presentation of epithelial downgrowth (ED) after clear cornea cataract extraction, characterized by mixed clinical expression of both cystic and diffuse form and massive epithelial debris seeding in anterior chamber, associated with scleral involvement. METHODS: In this case report, fine needle anterior chamber aspiration cytology was performed to identify pathologic tissue invading iris, cornea, and angular structures. The patient was treated with anterior chamber membrane surgical excision. RESULTS: Epithelial downgrowth was identified by cytologic assessment. The patient was treated with epithelial membrane peeling and scleral defect conjunctival covering. This conservative surgical approach led to a significant reduction of ocular pain. During follow-up, residual epithelial tissue was present in anterior chamber without tendency to regrowth. CONCLUSIONS: In doubtful cases of ED, histocytopathologic analysis should be performed without hesitation. Avoiding more invasive procedures, early detection and prompt surgical approach can result in improved outcome even in case of extensive intraocular involvement.


Assuntos
Câmara Anterior/patologia , Doenças da Córnea/diagnóstico , Epitélio Corneano/patologia , Facoemulsificação/efeitos adversos , Doenças da Esclera/diagnóstico , Idoso de 80 Anos ou mais , Córnea/cirurgia , Doenças da Córnea/etiologia , Doenças da Córnea/cirurgia , Feminino , Humanos , Microcirurgia , Doenças da Esclera/etiologia , Doenças da Esclera/cirurgia
14.
ACS Appl Mater Interfaces ; 8(4): 2644-51, 2016 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-26754413

RESUMO

The fabrication of organic electronic devices involving complex stacks of solution-processable functional materials has proven challenging. Significant material intermixing often occurs as a result of cross-solubility and postdeposition treatments, rendering the realization of even the simplest bilayer architectures rather cumbersome. In this study we investigate the feasibility of a dry transfer printing process for producing abrupt bilayer organic photodiodes (OPDs) and the effect of thermal annealing on the integrity of the bilayer. The process involves the transfer of readily deposited thin films of poly(3-hexylthiophene-2,5-diyl) (P3HT) and [6,6]-phenyl C61 butyric acid methyl ester (PCBM) using a polydimethylsiloxane (PDMS) stamp. Fabricated structures are characterized by means of cross-sectional scanning electron microscopy (SEM), UV/vis absorption spectroscopy, and time-of-flight secondary ion mass spectrometry (TOF-SIMS). Joint consideration of all results unveils abrupt interfaces with no thermal treatment applied and significant material intermixing for samples annealed above 100 °C. The role of the thermally assisted intermixing in determining the performance of complete devices is evaluated through the comparison of J-V characteristics and external quantum efficiencies (EQEs) of identical photodiodes subject to different annealing conditions. It is shown that the performance of such devices approaches the one of bulk heterojunction photodiodes upon thermal annealing at 140 °C for 5 min. Our results demonstrate that transfer printing is a reliable and simple process for the realization of functional multilayers, paving the way for organic electronic devices incorporating complex stacks. It further contributes to a fundamental understanding of material composition within photoactive layers by elucidating the process of thermally assisted intermixing.

15.
Nanoscale Res Lett ; 11(1): 143, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26976429

RESUMO

In this work, we present a method for printing metal micro- and nanopatterns down to sub-50-nm feature sizes using replicated, defect-tolerant stamps made out of OrmoStamp®; material. The relevant parameters for a successful transfer over large areas were investigated and yields above 99 % have been achieved. Comparing our results to conventional nano-transfer printing using PDMS stamps, we find that the more rigid hybrid polymer used here prevents unintended transfer from interspaces between structures of large distance due to roof collapse and deformation of nano-sized structures due to lateral collapse. Yet, our stamps are flexible enough to ensure intimate contact with the underlying substrate over large areas even in the presence of defect particles. Additionally, the presented patterning technique is resist-, solvent-, and chemical-free and is therefore ideally suited for applications in organic nanoelectronics where standard nanostructuring methods can harm or destroy the organic material.

16.
Eur J Ophthalmol ; 26(5): 398-404, 2016 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-26868006

RESUMO

PURPOSE: To survey the surgical routines with regards to prophylactic strategies in a sample of Italian hospitals and compare these with European Society for Cataract and Refractive Surgery (ESCRS) guidelines. METHODS: Six private and 18 public hospitals were included in this clinical-based retrospective study. The overall volume of cataract operations in the 24 centers in 2013 was 43,553. Main outcome measure was incidence of endophthalmitis per 1,000. An incidence of less than 0.13% was considered acceptable. RESULTS: Our study provides the first Italian data on the use of intracameral antibiotics in cataract surgery as recommended by the ESCRS. Thirteen centers (54%) used intracameral cefuroxime at the end of surgery. Of the 13 centers that used cefuroxime, 8 (62%) had an incidence of endophthalmitis less than 0.13%. Of the 7 (29%) centers that did not use intracameral cefuroxime, all had an endophthalmitis rate of greater than 0.13%. This difference was statistically significant (p<0.05). Among the 4 centers not included, 2 used vancomycin in the infusion bottle, 1 a fluoroquinolone, and the last a combination of antibiotics. The majority of surgeons (71%) used preoperative antibiotic eyedrops, but this measure was not shown to be significantly protective. CONCLUSIONS: Slightly more than half of the centers surveyed in this study adhered to the recommendations of the ESCRS and routinely employed prophylactic intracameral cefuroxime. An incidence of endophthalmitis greater than 0.13% was encountered significantly more frequently among centers that did not employ intracameral cefuroxime.


Assuntos
Antibioticoprofilaxia , Extração de Catarata/normas , Cefuroxima/uso terapêutico , Fidelidade a Diretrizes/estatística & dados numéricos , Oftalmologistas/normas , Guias de Prática Clínica como Assunto/normas , Procedimentos Cirúrgicos Refrativos/normas , Antibacterianos/uso terapêutico , Endoftalmite/epidemiologia , Endoftalmite/prevenção & controle , Feminino , Inquéritos Epidemiológicos , Humanos , Itália , Masculino , Oftalmologia/organização & administração , Estudos Retrospectivos , Sociedades Médicas/normas , Inquéritos e Questionários
17.
J Ophthalmol ; 2016: 4625096, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27885337

RESUMO

Aims. The study aimed to present the experience of a screening programme for early detection of diabetic retinopathy (DR) using a nonmydriatic fundus camera, evaluating the feasibility in terms of validity, resources absorption, and future advantages of a potential application, in an Italian local health authority. Methods. Diabetic patients living in the town of Ponzano, Veneto Region (Northern Italy), were invited to be enrolled in the screening programme. The "no prevention strategy" with the inclusion of the estimation of blindness related costs was compared with screening costs in order to evaluate a future extensive and feasible implementation of the procedure, through a budget impact approach. Results. Out of 498 diabetic patients eligible, 80% was enrolled in the screening programme. 115 patients (34%) were referred to an ophthalmologist and 9 cases required prompt treatment for either proliferative DR or macular edema. Based on the pilot data, it emerged that an extensive use of the investigated screening programme, within the Greater Treviso area, could prevent 6 cases of blindness every year, resulting in a saving of €271,543.32 (-13.71%). Conclusions. Fundus images obtained with a nonmydriatic fundus camera could be considered an effective, cost-sparing, and feasible screening tool for the early detection of DR, preventing blindness as a result of diabetes.

19.
IEEE Trans Image Process ; 12(10): 1259-73, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-18237891

RESUMO

We present a new image segmentation algorithm based on a tree-structured binary MRF model. The image is recursively segmented in smaller and smaller regions until a stopping condition, local to each region, is met. Each elementary binary segmentation is obtained as the solution of a MAP estimation problem, with the region prior modeled as an MRF. Since only binary fields are used, and thanks to the tree structure, the algorithm is quite fast, and allows one to address the cluster validation problem in a seamless way. In addition, all field parameters are estimated locally, allowing for some spatial adaptivity. To improve segmentation accuracy, a split-and-merge procedure is also developed and a spatially adaptive MRF model is used. Numerical experiments on multispectral images show that the proposed algorithm is much faster than a similar reference algorithm based on "flat" MRF models, and its performance, in terms of segmentation accuracy and map smoothness, is comparable or even superior.

20.
ACS Appl Mater Interfaces ; 6(13): 10593-601, 2014 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-24914700

RESUMO

In this study, we demonstrate the feasibility of TCO-free, fully sprayed organic photodiodes on flexible polyethylene terephthalate (PET) substrates. Transparent conducting films of single-wall carbon nanotubes are spray deposited from aqueous solutions. Low roughness is achieved, and films with sheet resistance values of 160 Ω/sq at 84% in transmittance are fabricated. Process issues related to the wetting of CNTs are then examined and solved, enabling successive spray depositions of a poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) layer and a blend of regioregular poly(3-hexylthiophene-2,5-diyl) and [6,6]-phenyl C61 butyric acid methyl ester (PCBM). The active layer is then optimized, achieving a process yield above 90% and dark currents as low as 10(-4) mA/cm(2). An external quantum efficiency of 65% and high reproducibility in the performance of the devices are obtained. Finally, the impact of the characteristics of the transparent electrode (transmittance and sheet resistance) on the performances of the device are investigated and validated through a theoretical model and experimental data.

SELEÇÃO DE REFERÊNCIAS
Detalhe da pesquisa