Abstract
A high photovoltage is an essential ingredient for the construction of a high-efficiency quantum dot sensitized solar cell (QDSSC). In this paper we present a novel configuration of QDSSC which incorporates the photoinduced dipole (PID) phenomenon for improved open circuit voltage (Voc). This configuration, unlike previously studied ones with molecular dipoles, is based on a dipole moment which is created only under illumination and is a result of exciton dissociation. The generation of photodipoles was achieved by the creation of long-lived trapped holes inside a core of type-II ZnSe/CdS colloidal core/shell QDs, which are placed on top of the standard CdS QD sensitizer layer. Upon photoexcitation, the created photodipole negatively shifts the TiO2 energy bands, resulting in a photovoltage that is higher by ∼100 mV compared to the standard cell, without type-II QDs. The extra photovoltage gained diminishes the excessive overpotential losses caused by the energetic difference between the CdS sensitizer layer and the TiO2, without harming the charge injection processes. Moreover, we show that the extent of the additional photovoltage is controlled by the illumination intensity. This work provides new understanding regarding the operation mechanisms of photoelectrochemical cells, while presenting a new strategy for constructing a high-voltage QDSSCs. In addition, the PID effect has the potential to be implemented in other promising photovoltaic technologies.
| Original language | English |
|---|---|
| Pages (from-to) | 4456-4461 |
| Number of pages | 6 |
| Journal | Nano Letters |
| Volume | 13 |
| Issue number | 9 |
| DOIs | |
| Publication status | Published - Sep 11 2013 |
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Keywords
- dipole moment
- high photovoltage cell
- quantum dot sensitized solar cell
- Solar energy
- type-II QDs
ASJC Scopus subject areas
- Condensed Matter Physics
- Bioengineering
- Chemistry(all)
- Materials Science(all)
- Mechanical Engineering
Cite this
Photo-induced dipoles : A new method to convert photons into photovoltage in quantum dot sensitized solar cells. / Buhbut, Sophia; Itzhakov, Stella; Hod, Idan; Oron, Dan; Zaban, Arie.
In: Nano Letters, Vol. 13, No. 9, 11.09.2013, p. 4456-4461.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Photo-induced dipoles
T2 - A new method to convert photons into photovoltage in quantum dot sensitized solar cells
AU - Buhbut, Sophia
AU - Itzhakov, Stella
AU - Hod, Idan
AU - Oron, Dan
AU - Zaban, Arie
PY - 2013/9/11
Y1 - 2013/9/11
N2 - A high photovoltage is an essential ingredient for the construction of a high-efficiency quantum dot sensitized solar cell (QDSSC). In this paper we present a novel configuration of QDSSC which incorporates the photoinduced dipole (PID) phenomenon for improved open circuit voltage (Voc). This configuration, unlike previously studied ones with molecular dipoles, is based on a dipole moment which is created only under illumination and is a result of exciton dissociation. The generation of photodipoles was achieved by the creation of long-lived trapped holes inside a core of type-II ZnSe/CdS colloidal core/shell QDs, which are placed on top of the standard CdS QD sensitizer layer. Upon photoexcitation, the created photodipole negatively shifts the TiO2 energy bands, resulting in a photovoltage that is higher by ∼100 mV compared to the standard cell, without type-II QDs. The extra photovoltage gained diminishes the excessive overpotential losses caused by the energetic difference between the CdS sensitizer layer and the TiO2, without harming the charge injection processes. Moreover, we show that the extent of the additional photovoltage is controlled by the illumination intensity. This work provides new understanding regarding the operation mechanisms of photoelectrochemical cells, while presenting a new strategy for constructing a high-voltage QDSSCs. In addition, the PID effect has the potential to be implemented in other promising photovoltaic technologies.
AB - A high photovoltage is an essential ingredient for the construction of a high-efficiency quantum dot sensitized solar cell (QDSSC). In this paper we present a novel configuration of QDSSC which incorporates the photoinduced dipole (PID) phenomenon for improved open circuit voltage (Voc). This configuration, unlike previously studied ones with molecular dipoles, is based on a dipole moment which is created only under illumination and is a result of exciton dissociation. The generation of photodipoles was achieved by the creation of long-lived trapped holes inside a core of type-II ZnSe/CdS colloidal core/shell QDs, which are placed on top of the standard CdS QD sensitizer layer. Upon photoexcitation, the created photodipole negatively shifts the TiO2 energy bands, resulting in a photovoltage that is higher by ∼100 mV compared to the standard cell, without type-II QDs. The extra photovoltage gained diminishes the excessive overpotential losses caused by the energetic difference between the CdS sensitizer layer and the TiO2, without harming the charge injection processes. Moreover, we show that the extent of the additional photovoltage is controlled by the illumination intensity. This work provides new understanding regarding the operation mechanisms of photoelectrochemical cells, while presenting a new strategy for constructing a high-voltage QDSSCs. In addition, the PID effect has the potential to be implemented in other promising photovoltaic technologies.
KW - dipole moment
KW - high photovoltage cell
KW - quantum dot sensitized solar cell
KW - Solar energy
KW - type-II QDs
UR - http://www.scopus.com/inward/record.url?scp=84884228710&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84884228710&partnerID=8YFLogxK
U2 - 10.1021/nl402360f
DO - 10.1021/nl402360f
M3 - Article
C2 - 23937343
AN - SCOPUS:84884228710
VL - 13
SP - 4456
EP - 4461
JO - Nano Letters
JF - Nano Letters
SN - 1530-6984
IS - 9
ER -