| 1. |
- Bauer, Christophe, et al.
(författare)
-
Electron injection and recombination in Ru(dcbpy)(2)(NCS)(2) sensitized nanostructured ZnO
- 2001
-
Ingår i: JOURNAL OF PHYSICAL CHEMISTRY B. - : AMER CHEMICAL SOC. - 1089-5647. ; 105:24, s. 5585-5588
-
Tidskriftsartikel (refereegranskat)abstract
- The dynamics of electron-transfer processes between bis(tetrabutylammonium) cis-bis(thiocyanato)bis(2,2'-bypiridine-4,4'-dicarboxylato)ruthenium(II) (called N719) and nanostructured ZnO films have been investigated by femtosecond and nanosecond spectrosco
|
|
| 2. |
|
|
| 3. |
|
|
| 4. |
- Borgström, Magnus, et al.
(författare)
-
Sensitized hole injection of phosphorus porphyrin into NiO : Toward new photovoltaic devices
- 2005
-
Ingår i: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-6106 .- 1520-5207. ; 109:48, s. 22928-22934
-
Tidskriftsartikel (refereegranskat)abstract
- This paper describes the preparation and the characterization of a photovoltaic cell based on the sensitization of a wide band gap p-type semiconductor (NiO) with a phosphorus porphyrin. A photophysical study with femtosecond transient absorption spectroscopy showed that light excitation of the phosphorus porphyrin chemisorbed on NiO particles induces a very rapid interfacial hole injection into the valence band of NiO, occurring mainly on the 2-20 ps time scale. This is followed by a recombination in which ca. 80% of the ground-state reactants are regenerated within 1 ns. A photoelectrochernical device, prepared with a nanocrystalline NiO electrode coated with the phosphorus porphyrin, yields a cathodic photocurrent indicating that electrons indeed flow from the NiO electrode toward the solution. The low incident-to-photocurrent efficiency (IPCE) can be rationalized by the rapid back recombination reaction between the reduced sensitizer and the injected hole which prevents an efficient regeneration of the sensitizer ground state from the iodide/triiodide redox mediator. To the best of our knowledge, this work represents the first example of a photovoltaic cell in which a mechanism of hole photoinjection has been characterized.
|
|
| 5. |
- Eilers, Gerriet, et al.
(författare)
-
The Radiocarbon Intracavity Optogalvanic Spectroscopy Setup at Uppsala
- 2013
-
Ingår i: Radiocarbon. - : Cambridge University Press (CUP). - 0033-8222 .- 1945-5755. ; 55:3-4, s. 237-250
-
Tidskriftsartikel (refereegranskat)abstract
- Accelerator mass spectrometry (AMS) is by far the predominant technology deployed for radiocarbon tracer studies. Applications are widespread from archaeology to biological, environmental, and pharmaceutical sciences. In spite of its excellent performance, AMS is expensive and complicated to operate. Consequently, alternative detection techniques for 14C are of great interest, with the vision of a compact, user-friendly, and inexpensive analytical method. Here, we report on the use of intracavity optogalvanic spectroscopy (ICOGS) for measurements of the 14C/12C ratio. This new detection technique was developed by Murnick et al. (2008). In the infrared (IR) region, CO2 molecules have strong absorption coefficients. The IR-absorption lines are narrow in line width and shifted for different carbon isotopes. These properties can potentially be exploited to detect 14CO2, 13CO2, or 12CO2 molecules unambiguously. In ICOGS, the sample is in the form of CO2 gas, eliminating the graphitization step that h is required in most AMS labs. The status of the ICOGS setup in Uppsala is presented. The system is operational but not yet fully developed. Data are presented for initial results that illustrate the dependence of the optogalvanic signal on various parameters, such as background and plasma-induced changes in the sample gas composition.
|
|
| 6. |
- Figgemeier, Egbert, et al.
(författare)
-
Modification of electron transfer properties in photoelectrochemical solar cells by substituting {Ru(terpy)(2)}(2+) dyes with thiophene
- 2004
-
Ingår i: Inorganic Chemistry Communications. - : Elsevier BV. - 1387-7003 .- 1879-0259. ; 7:1, s. 117-121
-
Tidskriftsartikel (refereegranskat)abstract
- A comparison of the properties of the 2-thienyl-substituted carboxyphenyl {RuII(terpy)2} dyes with their non-substituted analogues has enabled us to gain insight into the electronic properties that are prerequisite for efficient electron injection into the TiO2 conduction band in photoelectrochemical solar cells. Introducing the thienyl group has a profound effect upon the efficiency of photoinduced electron injection. This effect can be explained by a significant shift in the LUMO position from the terpy ligand anchored on the TiO2 surface towards the 2-thienyl substituted ligand, which is shown by means of electrochemistry and semiempirical calculations.
|
|
| 7. |
- Habenicht, Anja, et al.
(författare)
-
Two-photon excitation and time-resolved fluorescence: I. The proper response function for analysing single-photon counting experiments
- 2002
-
Ingår i: Chemical Physics Letters. ; 354:5-6, s. 367-75
-
Tidskriftsartikel (refereegranskat)abstract
- An accurate instrumental response function is needed to deconvolute fluorescence data obtained by time-correlated single-photon counting (TCSPC) upon multi-photon excitation. Hitherto the response function was obtained by measuring Rayleigh scattering (RS) from colloidal solutions, as is also used in one-photon excited fluorescence. We show that hyper Rayleigh scattering (HRS) provides a better choice for deconvolution of fluorescence decays, as obtained by TCSPC and two-photon excitation (TPE). The one- and two-photon response functions were monitored as RS and HRS from colloidal gold particles at 800 and 400 nm, respectively.
|
|
| 8. |
|
|
| 9. |
|
|
| 10. |
|
|
