Strongly Bound Frenkel Excitons on TiO2 Nanoparticles: An Evolutionary and DFT Approach
An evolutionary algorithm was employed to locate the global minimum of TiO2n nanoparticles with n=2–20. More than 61,000 structures were calculated with a semiempirical method and reoptimized using density functional theory. The exciton binding energy of TiO2 nanoparticles was determined through the...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Wiley
2024-01-01
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| Series: | International Journal of Photoenergy |
| Online Access: | http://dx.doi.org/10.1155/2024/4014216 |
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| author | Oscar Olvera-Neria Raúl García-Cruz Julio Gonzalez-Torres Luz María García-Cruz Jean Luis Castillo-Sánchez Enrique Poulain |
| author_facet | Oscar Olvera-Neria Raúl García-Cruz Julio Gonzalez-Torres Luz María García-Cruz Jean Luis Castillo-Sánchez Enrique Poulain |
| author_sort | Oscar Olvera-Neria |
| collection | DOAJ |
| description | An evolutionary algorithm was employed to locate the global minimum of TiO2n nanoparticles with n=2–20. More than 61,000 structures were calculated with a semiempirical method and reoptimized using density functional theory. The exciton binding energy of TiO2 nanoparticles was determined through the fundamental and optical band gap. Frenkel exciton energy scales as EB eV=8.07/n0.85, resulting in strongly bound excitons of 0.132–1.2 eV for about 1.4 nm nanoparticles. Although the exciton energy decreases with the system size, these tightly bound Frenkel excitons inhibit the separation of photogenerated charge carriers, making their application in photocatalysis and photovoltaic devices difficult, and imposing a minimum particle size. In contrast, the exciton binding energy of rutile is 4 meV, where the Wannier exciton energy scales as EB eV=13.61 μ/ε2. Moreover, the Wannier excitons in bulk TiO2 are delocalized according to the Bohr radii: 3.9 nm for anatase and 7.7 nm for rutile. |
| format | Article |
| id | doaj-art-f5e7598bb16b4c43b9a6b64e5ea3c2d6 |
| institution | OA Journals |
| issn | 1687-529X |
| language | English |
| publishDate | 2024-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | International Journal of Photoenergy |
| spelling | doaj-art-f5e7598bb16b4c43b9a6b64e5ea3c2d62025-08-20T02:22:26ZengWileyInternational Journal of Photoenergy1687-529X2024-01-01202410.1155/2024/4014216Strongly Bound Frenkel Excitons on TiO2 Nanoparticles: An Evolutionary and DFT ApproachOscar Olvera-Neria0Raúl García-Cruz1Julio Gonzalez-Torres2Luz María García-Cruz3Jean Luis Castillo-Sánchez4Enrique Poulain5Applied Molecular Atomic Physics Area (FAMA)Applied Molecular Atomic Physics Area (FAMA)Applied Molecular Atomic Physics Area (FAMA)Applied Molecular Atomic Physics Area (FAMA)Applied Molecular Atomic Physics Area (FAMA)Applied Molecular Atomic Physics Area (FAMA)An evolutionary algorithm was employed to locate the global minimum of TiO2n nanoparticles with n=2–20. More than 61,000 structures were calculated with a semiempirical method and reoptimized using density functional theory. The exciton binding energy of TiO2 nanoparticles was determined through the fundamental and optical band gap. Frenkel exciton energy scales as EB eV=8.07/n0.85, resulting in strongly bound excitons of 0.132–1.2 eV for about 1.4 nm nanoparticles. Although the exciton energy decreases with the system size, these tightly bound Frenkel excitons inhibit the separation of photogenerated charge carriers, making their application in photocatalysis and photovoltaic devices difficult, and imposing a minimum particle size. In contrast, the exciton binding energy of rutile is 4 meV, where the Wannier exciton energy scales as EB eV=13.61 μ/ε2. Moreover, the Wannier excitons in bulk TiO2 are delocalized according to the Bohr radii: 3.9 nm for anatase and 7.7 nm for rutile.http://dx.doi.org/10.1155/2024/4014216 |
| spellingShingle | Oscar Olvera-Neria Raúl García-Cruz Julio Gonzalez-Torres Luz María García-Cruz Jean Luis Castillo-Sánchez Enrique Poulain Strongly Bound Frenkel Excitons on TiO2 Nanoparticles: An Evolutionary and DFT Approach International Journal of Photoenergy |
| title | Strongly Bound Frenkel Excitons on TiO2 Nanoparticles: An Evolutionary and DFT Approach |
| title_full | Strongly Bound Frenkel Excitons on TiO2 Nanoparticles: An Evolutionary and DFT Approach |
| title_fullStr | Strongly Bound Frenkel Excitons on TiO2 Nanoparticles: An Evolutionary and DFT Approach |
| title_full_unstemmed | Strongly Bound Frenkel Excitons on TiO2 Nanoparticles: An Evolutionary and DFT Approach |
| title_short | Strongly Bound Frenkel Excitons on TiO2 Nanoparticles: An Evolutionary and DFT Approach |
| title_sort | strongly bound frenkel excitons on tio2 nanoparticles an evolutionary and dft approach |
| url | http://dx.doi.org/10.1155/2024/4014216 |
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