This is the first comprehensive review on methods and materials for use in optical sensing of pH values and on applications of such sensors. The Review starts with an introduction that contains subsections on the definition of the pH value, a brief look back on optical methods for sensing of pH, on the effects of ionic strength on pH values and pKa values, on the selectivity, sensitivity, precision, dynamic ranges, and temperature dependence of such sensors. Commonly used optical sensing schemes are covered in a next main chapter, with subsections on methods based on absorptiometry, reflectometry, luminescence, refractive index, surface plasmon resonance, photonic crystals, turbidity, mechanical displacement, interferometry, and solvatochromism. This is followed by sections on absorptiometric and luminescent molecular probes for use pH in sensors. Further large sections cover polymeric hosts and supports, and methods for immobilization of indicator dyes. Further and more specific sections summarize the state of the art in materials with dual functionality (indicator and host), nanomaterials, sensors based on upconversion and 2-photon absorption, multiparameter sensors, imaging, and sensors for extreme pH values. A chapter on the many sensing formats has subsections on planar, fiber optic, evanescent wave, refractive index, surface plasmon resonance and holography based sensor designs, and on distributed sensing. Another section summarizes selected applications in areas, such as medicine, biology, oceanography, bioprocess monitoring, corrosion studies, on the use of pH sensors as transducers in biosensors and chemical sensors, and their integration into flow-injection analyzers, microfluidic devices, and lab-on-a-chip systems. An extra section is devoted to current challenges, with subsections on challenges of general nature and those of specific nature. A concluding section gives an outlook on potential future trends and perspectives.

Optical Sensing and Imaging of pH Values: Spectroscopies, Materials, and Applications

Fiber Optic Sensor Designs and Luminescence-based Methods for the detection of Oxygen and pH measurement

Since its first creation, glass has always fascinated with its optical properties, its ability to let light through without being invisible. One of the most spectacular achievements of optical glass is the optical fiber for which considerable work has been done to make it as transparent as possible. However, for twenty years, contrary to this quest for transparency, nanoparticles have been inserted into optical fibres. First designed to develop new lasers and amplifiers, the lowest possible particle-induced light scattering then sought has for the last four years, on the contrary, been exacerbated in order to develop new sensors. 

Nanoparticles in optical fiber, issue andopportunity of light scattering

Particles in the core of optical fibers are widely studied to tailor or to improve optical properties. The analysis of nanoparticles embedded in silica-based optical fiber allowed new observations of the evolution of amorphous particles during fiber drawing. Even at the nanoscale, competition between viscous stresses and surface tension on the particles induces elongation and even break-up of particles during the process. Indeed, particles between 140 and 200 nm diameter inside the preform can break up in fragments with diameters down to 60 nm inside the drawn fiber. Break-up of particles appears as a new " top-down " strategy to produce small particles. These observations are promising for micro/nanostructured and multiphasic optical fibers.

Fiber-draw-induced elongation and break-up of particles inside the core of a silica-based optical fiber

Luminescence and laser properties of RE-doped silica optical fibers: The role of composition, fabrication processing, and inter-ionic energy transfers

Thermal stability and photoluminescence properties of RE-doped (RE = Ho, Er, Tm) alumina nanoparticles in bulk and fiber-optic silica glass

In medicine knowledge of pH values can provide us with information not only about the patients’ status but also about physiological processes in the patient’s body. Measurements of pH in small-sample volumes and online pH monitoring in vivo can be employed to obtain such information. For such measurements we have developed and investigated U-shaped fiber-optic probes with immobilized pH indicators in this paper. U-shaped probes with a diameter of about 2 mm were prepared. Three different pH indicators, methyl red, methyl orange, and bromothymol blue, were immobilized in two types of matrices, namely, porous silica (PS) and ethylcellulose (EC), and applied on the U-shaped probes. Changes in spectra of transmitted power were measured and calibration curves were determined from these spectra. It has been found that a working pH range of prepared probes was from 3.1 to 7.6. The maximum sensitivity was about 0.1 1/pH unit. Effects of structural relaxations of detection layers and indicator leaching observed in experiments are discussed.

/pdf/optical-ph-detection-with-u-shaped-fiber-optic-probes-and-4eg25n8ryh.pdf

Optical pH Detection with U-Shaped Fiber-Optic Probes and Absorption Transducers

Nanocrystalline Zn2TiO4 films for distributed Bragg's reflectors operating in near infrared region

The paper presents results on preparation and characterization of highly reflective coatings on planar substrates and
inside silica tubes. Coatings are designed for a maximum reflectivity at a wavelength of 550 nm and consist of several
pairs of oxide layers. Each pair is composed of one layer with a high refractive index and one layer with a low refractive
index with a refractive-index contrast of about 1.1.
The layers were prepared by the sol-gel method. High-index layers were applied from a sol based on titanium butoxide
while a sol of tetramethoxysilane was use for low-index layers. The sols were deposited onto silica slides or onto walls
of silica tubes by using the dip-coating technique. Applied gel layers were thermally treated at temperatures up to 450 °C
in order to obtain densified layers with thicknesses 50-100 nm. Coatings with one to five pairs of layers were fabricated.
Prepared coatings were characterized by transmission and reflection spectrometry in a wavelength range from 190 to-
1100 nm, by contact profilometry, and by spectral ellipsometry. Thicknesses and refractive indices of coatings were
determined from these measurements. For normal light incidence a reflectivity higher than 99% in a wavelength range of
500-650 nm was measured by transmission spectrometry on coatings prepared from four or five pairs of layers. Similar
reflectivity values were determined for angles of incidence of 15, 30, 45 and 60 degrees by using reflection
spectrometry. Transmission spectra measured on the coated tubes which show interference bands are also presented in
the paper.

Preparation and characterization of coatings with a high reflectivity on planar substrates and inside silica tubes

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Ivo Bartoň

Author Tools

Chat about Author

Papers

Thermal stability and photoluminescence properties of RE-doped (RE = Ho, Er, Tm) alumina nanoparticles in bulk and fiber-optic silica glass

Optical pH Detection with U-Shaped Fiber-Optic Probes and Absorption Transducers

Nanocrystalline Zn2TiO4 films for distributed Bragg's reflectors operating in near infrared region

Preparation and characterization of coatings with a high reflectivity on planar substrates and inside silica tubes