Role of Interfacial Potential Drops on Redox‐Couple Dependent Voltages Using Hybridized Si(111)–(Bis)Anthracene Photoelectrodes
Abstract We investigate the flat band voltage (VFB) of silicon (Si) surfaces functionalized with methyl (Me), 9‐anthracene (Anth), 1,8‐anthracene (DiAnth; two attachment points), and 9‐bianthracene (BiAnth) on n‐type and p‐type Si substrates. Flat band potential (EFB, by Mott‐Schottky) provided VFB...
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Wiley-VCH
2024-12-01
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| Series: | ChemElectroChem |
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| Online Access: | https://doi.org/10.1002/celc.202400468 |
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| author | Hark Jin Kim Michael J. Rose |
| author_facet | Hark Jin Kim Michael J. Rose |
| author_sort | Hark Jin Kim |
| collection | DOAJ |
| description | Abstract We investigate the flat band voltage (VFB) of silicon (Si) surfaces functionalized with methyl (Me), 9‐anthracene (Anth), 1,8‐anthracene (DiAnth; two attachment points), and 9‐bianthracene (BiAnth) on n‐type and p‐type Si substrates. Flat band potential (EFB, by Mott‐Schottky) provided VFB (or VBI) dependent on the contacted redox couple (ERedox). On p‐type Si, VFB increased linearly until a limiting value was reached; similarly, the n‐type Si VFB decreased linearly until it plateaued at more negative potentials. Notably, the slope of VFB depended on the surface modifier, exhibiting opposite trends for p‐type and n‐type Si. Curiously, anthracene‐functionalized p‐Si exhibited an unexpectedly more shallow (and beneficial) slope than ‐methyl, attributed to the polarizability of the anthracene π electron cloud and a potential drop across the molecular interface. On n‐type Si, anthracene‐functionalized surfaces displayed a higher slope than ‐methyl, suggesting a gradual cancellation of the voltage shift effect due to a fixed surface dipole. We also quantified the interfacial potential drop across p‐Si–Anth as 275 mV using variable frequency (10 kHz vs 1 kHz) Mott‐Schottky analysis. The interfacial potential drop and dipoles that result from molecular functionalization are thus critical design parameters for PEC cells that utilize moderate‐potential redox couples or reactions; however, such effects are negligible with redox couples that reside at or beyond the semiconductor band‐edge. |
| format | Article |
| id | doaj-art-87dbe13a35dc481f8e29bdaae676c028 |
| institution | Kabale University |
| issn | 2196-0216 |
| language | English |
| publishDate | 2024-12-01 |
| publisher | Wiley-VCH |
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| spelling | doaj-art-87dbe13a35dc481f8e29bdaae676c0282024-12-16T08:33:20ZengWiley-VCHChemElectroChem2196-02162024-12-011124n/an/a10.1002/celc.202400468Role of Interfacial Potential Drops on Redox‐Couple Dependent Voltages Using Hybridized Si(111)–(Bis)Anthracene PhotoelectrodesHark Jin Kim0Michael J. Rose1Department of Chemistry The University of Texas at Austin 105E 24th St. Austin TX 78712 United StatesDepartment of Chemistry The University of Texas at Austin 105E 24th St. Austin TX 78712 United StatesAbstract We investigate the flat band voltage (VFB) of silicon (Si) surfaces functionalized with methyl (Me), 9‐anthracene (Anth), 1,8‐anthracene (DiAnth; two attachment points), and 9‐bianthracene (BiAnth) on n‐type and p‐type Si substrates. Flat band potential (EFB, by Mott‐Schottky) provided VFB (or VBI) dependent on the contacted redox couple (ERedox). On p‐type Si, VFB increased linearly until a limiting value was reached; similarly, the n‐type Si VFB decreased linearly until it plateaued at more negative potentials. Notably, the slope of VFB depended on the surface modifier, exhibiting opposite trends for p‐type and n‐type Si. Curiously, anthracene‐functionalized p‐Si exhibited an unexpectedly more shallow (and beneficial) slope than ‐methyl, attributed to the polarizability of the anthracene π electron cloud and a potential drop across the molecular interface. On n‐type Si, anthracene‐functionalized surfaces displayed a higher slope than ‐methyl, suggesting a gradual cancellation of the voltage shift effect due to a fixed surface dipole. We also quantified the interfacial potential drop across p‐Si–Anth as 275 mV using variable frequency (10 kHz vs 1 kHz) Mott‐Schottky analysis. The interfacial potential drop and dipoles that result from molecular functionalization are thus critical design parameters for PEC cells that utilize moderate‐potential redox couples or reactions; however, such effects are negligible with redox couples that reside at or beyond the semiconductor band‐edge.https://doi.org/10.1002/celc.202400468Surface dipolesBand bendingPotential dropSemiconductor-liquid interface |
| spellingShingle | Hark Jin Kim Michael J. Rose Role of Interfacial Potential Drops on Redox‐Couple Dependent Voltages Using Hybridized Si(111)–(Bis)Anthracene Photoelectrodes ChemElectroChem Surface dipoles Band bending Potential drop Semiconductor-liquid interface |
| title | Role of Interfacial Potential Drops on Redox‐Couple Dependent Voltages Using Hybridized Si(111)–(Bis)Anthracene Photoelectrodes |
| title_full | Role of Interfacial Potential Drops on Redox‐Couple Dependent Voltages Using Hybridized Si(111)–(Bis)Anthracene Photoelectrodes |
| title_fullStr | Role of Interfacial Potential Drops on Redox‐Couple Dependent Voltages Using Hybridized Si(111)–(Bis)Anthracene Photoelectrodes |
| title_full_unstemmed | Role of Interfacial Potential Drops on Redox‐Couple Dependent Voltages Using Hybridized Si(111)–(Bis)Anthracene Photoelectrodes |
| title_short | Role of Interfacial Potential Drops on Redox‐Couple Dependent Voltages Using Hybridized Si(111)–(Bis)Anthracene Photoelectrodes |
| title_sort | role of interfacial potential drops on redox couple dependent voltages using hybridized si 111 bis anthracene photoelectrodes |
| topic | Surface dipoles Band bending Potential drop Semiconductor-liquid interface |
| url | https://doi.org/10.1002/celc.202400468 |
| work_keys_str_mv | AT harkjinkim roleofinterfacialpotentialdropsonredoxcoupledependentvoltagesusinghybridizedsi111bisanthracenephotoelectrodes AT michaeljrose roleofinterfacialpotentialdropsonredoxcoupledependentvoltagesusinghybridizedsi111bisanthracenephotoelectrodes |