Ultrafast Charge Transfer from CdSe Quantum Dots to p-Type NiO: Hole Injection vs Hole Trapping
(2014) In Journal of Physical Chemistry C 118(32). p.18462-18471- Abstract
- Semiconductor quantum dot (QD) to metal oxide electron injection dynamics is well documented in the scientific literature. In contrast to that, not much is known so far about hole injection time scales in such systems. The current study fills this gap. We investigate photocathodes consisting of CdSe QDs and p-type NiO to study hole injection dynamics from the valence band of the QDs to NiO. The combination of two complementary techniques, ultrafast time-resolved absorption and fluorescence spectroscopies, enabled us to distinguish between hole trapping and injection. A kinetic component on the time scale of a few hundreds of picoseconds was identified as hole injection. By changing the size of the QDs, the driving force of the hole... (More)
- Semiconductor quantum dot (QD) to metal oxide electron injection dynamics is well documented in the scientific literature. In contrast to that, not much is known so far about hole injection time scales in such systems. The current study fills this gap. We investigate photocathodes consisting of CdSe QDs and p-type NiO to study hole injection dynamics from the valence band of the QDs to NiO. The combination of two complementary techniques, ultrafast time-resolved absorption and fluorescence spectroscopies, enabled us to distinguish between hole trapping and injection. A kinetic component on the time scale of a few hundreds of picoseconds was identified as hole injection. By changing the size of the QDs, the driving force of the hole injection was tuned and we demonstrated that the hole injection rates are well described by the Marcus theory of charge transfer. In order to enhance the overall hole injection efficiency, we have passivated the CdSe QDs by a gradient ZnS shell. The core-shell QDs show significantly slower hole injection; still, since trapping was almost eliminated, the overall hole injection efficiency was greatly enhanced. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/4656316
- author
- Zheng, Kaibo
LU
; Zidek, Karel
LU
; Qenawy, Mohamed
LU
; Zhang, Wei
LU
; Chabera, Pavel
LU
; Lenngren, Nils
LU
; Yartsev, Arkady
LU
and Pullerits, Tönu LU
- organization
- publishing date
- 2014
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Journal of Physical Chemistry C
- volume
- 118
- issue
- 32
- pages
- 18462 - 18471
- publisher
- The American Chemical Society (ACS)
- external identifiers
-
- wos:000340444500022
- scopus:84906266068
- ISSN
- 1932-7447
- DOI
- 10.1021/jp506963q
- language
- English
- LU publication?
- yes
- additional info
- The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Chemical Physics (S) (011001060)
- id
- dd7a9aac-6c90-4f8a-a06a-b15103285efd (old id 4656316)
- date added to LUP
- 2016-04-01 10:10:11
- date last changed
- 2023-11-09 13:44:47
@article{dd7a9aac-6c90-4f8a-a06a-b15103285efd, abstract = {{Semiconductor quantum dot (QD) to metal oxide electron injection dynamics is well documented in the scientific literature. In contrast to that, not much is known so far about hole injection time scales in such systems. The current study fills this gap. We investigate photocathodes consisting of CdSe QDs and p-type NiO to study hole injection dynamics from the valence band of the QDs to NiO. The combination of two complementary techniques, ultrafast time-resolved absorption and fluorescence spectroscopies, enabled us to distinguish between hole trapping and injection. A kinetic component on the time scale of a few hundreds of picoseconds was identified as hole injection. By changing the size of the QDs, the driving force of the hole injection was tuned and we demonstrated that the hole injection rates are well described by the Marcus theory of charge transfer. In order to enhance the overall hole injection efficiency, we have passivated the CdSe QDs by a gradient ZnS shell. The core-shell QDs show significantly slower hole injection; still, since trapping was almost eliminated, the overall hole injection efficiency was greatly enhanced.}}, author = {{Zheng, Kaibo and Zidek, Karel and Qenawy, Mohamed and Zhang, Wei and Chabera, Pavel and Lenngren, Nils and Yartsev, Arkady and Pullerits, Tönu}}, issn = {{1932-7447}}, language = {{eng}}, number = {{32}}, pages = {{18462--18471}}, publisher = {{The American Chemical Society (ACS)}}, series = {{Journal of Physical Chemistry C}}, title = {{Ultrafast Charge Transfer from CdSe Quantum Dots to p-Type NiO: Hole Injection vs Hole Trapping}}, url = {{http://dx.doi.org/10.1021/jp506963q}}, doi = {{10.1021/jp506963q}}, volume = {{118}}, year = {{2014}}, }