Topic
Photoexcitation
About: Photoexcitation is a research topic. Over the lifetime, 5874 publications have been published within this topic receiving 134733 citations.
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TL;DR: In this paper, the defects created at 4.2 K by the UV-irradiation of CsI:Tl crystals in the Tl+-related absorption bands (by photons of 5.8-4.8 eV energy) have been studied.
38 citations
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TL;DR: In this paper, a discussion of two-photon allowed and vibronically induced transitions is given, and a lower limit of 0.8 eV is set for the 1B3u-1B2g splitting which results from the interactions of the two pyrazine lone pair orbitals.
38 citations
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TL;DR: In this article, the authors used the contactless time-resolved microwave conductivity (TRMC) technique to investigate the photoconductance of CdS-coated mesoporous TiO2 and ZrO2.
Abstract: We use the contactless time-resolved microwave conductivity (TRMC) technique to investigate the photoconductance of CdS-coated mesoporous TiO2 and ZrO2. The CdS domains were grown directly on the surface of the oxide by a chemical bath deposition method. Mobile charge carriers are generated with a low yield following photoexcitation of CdS grown on ZrO2; there is no injection into the oxide and the short-lived photoconductance signal is attributed to the hole in CdS. In contrast, illumination of CdS domains grown on TiO2 results in very efficient electron injection into the TiO2 nanoparticles, producing long-lived charge carriers. We show that the quantum yield for electron injection into TiO2 per photon absorbed by the CdS sensitizer is close to unity. The photoconductance action spectrum follows the absorption of the CdS domains, which indicates that the charge injection efficiency does not depend on wavelength in the range where the CdS absorbs (425–550 nm).
38 citations
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TL;DR: In this article, the authors investigated the photoresponse of β-In2S3 thin films with a band gap of ∼2.67eV and found that the photoconductive response to extrinsic photoexcitation could be removed when the film stoichiometry was changed.
Abstract: β-In2S3 thin films with a band gap of ∼2.67eV exhibited persistent photoconductivity when excited using photons with energy of 1.96 eV. The photoconductive response to extrinsic photoexcitation could be removed when the film stoichiometry was changed. Photoluminescence studies in the films revealed an emission of 1.826 eV, due to donor–acceptor pair (DAP) recombination, which was absent in the film not responding to extrinsic excitation. Hence, it was concluded that presence of the DAP was responsible for the extrinsic photoconductivity under the 1.96 eV excitation. This study can initiate further a methodology for tailoring the photoresponse of this semiconducting thin film by spatially controlling the film stoichiometry.
38 citations
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TL;DR: In this article, a donor-πacceptor (D-π-A) type organic dye (coded as B2) was designed and synthesized for applications in dye-sensitized solar cells (DSSC).
Abstract: Although numerous donor-π-acceptor (D-π-A) type organic dyes were investigated in order to replace the ruthenium polypyridyl complexes, there have been few reports of the D-π-2A system and the related electron transfer processes. In this work, a novel D-π-2A dye (coded as B2) was designed and synthesized for applications in dye-sensitized solar cells (DSSC). Obvious intramolecular charge transfer (ICT) between the donor and acceptor takes place under photoexcitation. Three frontier LUMOs (LUMO, LUMO+1, LUMO+2) of B2 are all located on the acceptor part, which is highly favorable for intramolecular electron transfer from the donor to acceptors and enhances the electron injection into the semiconductors. DSSC based on B2 showed a maximum monochromatic incident photon-to-current efficiency (IPCE) of 68% at 425 nm and an overall power conversion efficiency of 3.62% under simulated solar light (AM 1.5G, 100 mW cm–2) irradiation. Femtosecond and nanosecond TA, and TCSPC techniques were used to monitor the photo...
38 citations