Determining Bandgap of Thermochromic Phosphor Films via Reflectance Measurements under Controlled Heating
In this article, we present a method to determine the bandgap of a thermochromic phosphor film by simple reflectance measurements under controlled heating. The phosphor is illuminated by a light-emitting diode while being heated continuously. The reflected light is detected using a calibrated photod...
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| Language: | English |
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Kabale University
2024
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| Online Access: | http://hdl.handle.net/20.500.12493/2324 |
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| author | Katashaya, Steven Rwabona |
| author_facet | Katashaya, Steven Rwabona |
| author_sort | Katashaya, Steven Rwabona |
| collection | KAB-DR |
| description | In this article, we present a method to determine the bandgap of a thermochromic phosphor film by simple reflectance measurements under controlled heating. The phosphor is illuminated by a light-emitting diode while being heated continuously. The reflected light is detected using a calibrated photodiode circuit based on an operational transconductance amplifier. We apply the Schuster Kubelka-Munk function to deduce the absorbance over temperature and thus the bandgap. We show, for the first time, that the thermochromic phosphor's color change follows Arrhenius's Law and therefore involves activation energy. We estimate the bandgap to be between 1.1 eV and 1.9 eV and find an activation energy of 46.67 ±1.6 kJ/mol. The simplicity of the approach will appeal to undergraduate teachers and students of physics and materials science. The technique can be used to investigate other thermochromic materials as well. |
| format | Article |
| id | oai:idr.kab.ac.ug:20.500.12493-2324 |
| institution | KAB-DR |
| language | English |
| publishDate | 2024 |
| publisher | Kabale University |
| record_format | dspace |
| spelling | oai:idr.kab.ac.ug:20.500.12493-23242024-10-16T00:01:02Z Determining Bandgap of Thermochromic Phosphor Films via Reflectance Measurements under Controlled Heating Katashaya, Steven Rwabona Reflectance Absorbance Thermochromism Phosphors Bandgap Activation Energy In this article, we present a method to determine the bandgap of a thermochromic phosphor film by simple reflectance measurements under controlled heating. The phosphor is illuminated by a light-emitting diode while being heated continuously. The reflected light is detected using a calibrated photodiode circuit based on an operational transconductance amplifier. We apply the Schuster Kubelka-Munk function to deduce the absorbance over temperature and thus the bandgap. We show, for the first time, that the thermochromic phosphor's color change follows Arrhenius's Law and therefore involves activation energy. We estimate the bandgap to be between 1.1 eV and 1.9 eV and find an activation energy of 46.67 ±1.6 kJ/mol. The simplicity of the approach will appeal to undergraduate teachers and students of physics and materials science. The technique can be used to investigate other thermochromic materials as well. 2024-10-15T06:39:56Z 2024-10-15T06:39:56Z 2024 Article Katashaya, Steven Rwabona (2024). Determining Bandgap of Thermochromic Phosphor Films via Reflectance Measurements under Controlled Heating. Kabale: Kabale University. http://hdl.handle.net/20.500.12493/2324 en Attribution-NonCommercial-NoDerivs 3.0 United States http://creativecommons.org/licenses/by-nc-nd/3.0/us/ application/pdf Kabale University |
| spellingShingle | Reflectance Absorbance Thermochromism Phosphors Bandgap Activation Energy Katashaya, Steven Rwabona Determining Bandgap of Thermochromic Phosphor Films via Reflectance Measurements under Controlled Heating |
| title | Determining Bandgap of Thermochromic Phosphor Films via Reflectance Measurements under Controlled Heating |
| title_full | Determining Bandgap of Thermochromic Phosphor Films via Reflectance Measurements under Controlled Heating |
| title_fullStr | Determining Bandgap of Thermochromic Phosphor Films via Reflectance Measurements under Controlled Heating |
| title_full_unstemmed | Determining Bandgap of Thermochromic Phosphor Films via Reflectance Measurements under Controlled Heating |
| title_short | Determining Bandgap of Thermochromic Phosphor Films via Reflectance Measurements under Controlled Heating |
| title_sort | determining bandgap of thermochromic phosphor films via reflectance measurements under controlled heating |
| topic | Reflectance Absorbance Thermochromism Phosphors Bandgap Activation Energy |
| url | http://hdl.handle.net/20.500.12493/2324 |
| work_keys_str_mv | AT katashayastevenrwabona determiningbandgapofthermochromicphosphorfilmsviareflectancemeasurementsundercontrolledheating |