Mr. Dawei Yin Profile

Dawei Yin

at Simon Fraser University

SPIE Involvement:

Author

Publications (4)

Proceedings Article | 11 March 2024 Presentation + Paper

Sum of integrated emissions detecting ammonia from 1 to 10,000 PPM using 405 nm induced fluorescence of vapochromic coordination polymers

Glenn Chapman, Xin Wei, Dawei Yin, Bonnie Gray, Leanna Karn, Daniel Leznoff

Proceedings Volume 12893, 128930Q (2024) https://doi.org/10.1117/12.3003945

KEYWORDS: Fluorescence, Polymers, Spectroscopy, Fluorescence intensity, Sensors, Semiconductor lasers, Ultraviolet radiation, Fluorescence spectroscopy, Emission wavelengths, Light emitting diodes

Read Abstract +

Proceedings Article | 8 March 2023 Presentation + Paper

Enhancing detecting ammonia from 1 to 10,000’s PPM using laser-induced fluorescence of tuned vapochromic coordination polymers

Glenn Chapman, Dawei Yin, Viraj Patel, Bonnie Gray, Daniel Leznoff

Proceedings Volume 12428, 124280J (2023) https://doi.org/10.1117/12.2651067

KEYWORDS: Fluorescence, Polymers, Sensors, Spectroscopy, Semiconductor lasers, Fluorescence spectroscopy, Fluorescence intensity, Light emitting diodes, Ultraviolet radiation, Transformers

Read Abstract +

The detection of ammonia and similar gases over a wide range from a few Parts Per Millions (ppm) to 10,000’s ppm in a single sensor is important for industrial applications. We are exploring Vapochromic Coordination Polymers (VCP) specifically Zn[Au(CN)₂]₂, developed to achieve fluorescence when exposed to NH3. At high concentration of ammonia under UV stimulation VCP spectrally shifts its fluorescent peak from 470nm to 530nm while the intensity grows 3~5X. We use a 405nm laser diode excitation source which provides a narrow (4nm) stimulation clearly separated from the spectral peak. Focusing the emission on a USB portable spectrometer (430 to 700nm) at concentrations <1000 ppm of ammonia there is almost no peak wavelength spectral shift or intensity change and only subtle fluorescent spectrum alterations. To detect first we create a method that gives unique values over the range 1- <1000 ppm by dividing the spectrum into 10 nm bins, integrate the emission in each bin, relative to that of 0 ppm exposure, then sum all the bins (Sum of Integrated Emissions, SIE). The key analysis point is to note that the way the spectrum changes in each wavelength bin varies at different ammonia ppm exposures. SIE gives excellent sensitivity between 0-50 ppm and <400 ppm, but poor accuracy in the 100-500ppm range. Using the SIE to identify measurements in that region we switch to a second metric, Limited Range SIE, that covers only the 430-470nm bins but for 100-500ppm gives an accurate linear response. This shows that in many spectral fluorescence cases in the region where the longer wavelength peak begins to dominate looking at regions outside of the peak maximas is more accurate than including those within the unexposed to saturated exposure (eg ammonia) peak range. By creating a model assuming the fraction z of 0ppm and saturated spectrum are linearly combined we fit the measured spectrum using regression analysis to obtain the z value for all ppm measurements which show what is going on in the VCP conversion.

Proceedings Article | 5 March 2021 Presentation + Paper

Detecting PPM ammonia over wide range using laser induced fluorescence of vapochromic coordination polymers

Glenn Chapman, Dawei Yin, Bonnie Gray, Daniel Leznoff

Proceedings Volume 11693, 116930W (2021) https://doi.org/10.1117/12.2584207

KEYWORDS: Polymers, Laser induced fluorescence, Spectroscopy, Sensors, Semiconductor lasers, Near ultraviolet, Luminescence

Read Abstract +

Proceedings Article | 22 February 2018 Presentation + Paper

Detection of low-concentration ammonia using differential laser-induced fluorescence on vapochromic coordination polymers

Dawei Yin, Glenn Chapman, David Stevens, Bonnie Gray, Daniel Leznoff

Proceedings Volume 10539, 105390K (2018) https://doi.org/10.1117/12.2285686

KEYWORDS: Polymers, Sensors, Luminescence, Spectroscopy, Laser induced fluorescence, Semiconductor lasers, Calibration, Gases, Nitrogen, Spectral data processing

Read Abstract +

View contact details

UPDATE YOUR PROFILE

Is this your profile? Update it now.

Sign into your SPIE.org account

Don’t have a profile and want one?

Create an account on SPIE.org

Keywords/Phrases

Search In:

Publication Years