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Plasmon-enhanced electron injection in dye-sensitized solar cells
Recent experiments have shown that the efficiency of photoinduced electron transfer from sensitizers (molecules or quantum dots) to semiconductors can be enhanced by coupling the sensitizers to plasmon resonances in metal nanoparticles. Here, we use a model Hamiltonian approach to show theoretically that there is an optimal coupling be- tween the sensitizer and plasmons that maximizes the electron-transfer efficiency. This optimum results from the competition between electron transfer, plasmon relaxation and plasmon decoherence. For coupling values that exceed the optimal value, the dy- namics of electron transfer from the sensitizer to the semiconductor can be significantly modified due to the sensitizer-plasmon coupling.
Side Chain Engineering of Near-IR Aza-BODIPY Dyes Enables Processable Films with High Hole Mobility in Diodes
Boron chelated azadipyrromethene (Aza-BODIPY) derivatives are promising candidates for near-infrared optoelectronic applications due to their tunable absorption, electron-deficient core, and strong π-conjugation. Here, in this work, we synthesized and studied a series of 1-naphthylethynyl-substituted aza-BODIPY molecules featuring hexyl or hexyloxy solubilizing groups at either the proximal or the distal phenyl positions. These substitutions were designed to improve the solubility, film formation, and optoelectronic properties. We found that solubilizing groups not only enabled uniform solution-processed films but also fine-tuned key properties, such as absorption onset, oxidation potential, and energy levels. Charge transport analysis showed consistently high hole mobilities (∼10 –3 cm 2 /V s) across all substituted derivatives when CuI was used as the hole transport layer, regardless of film morphology. In contrast, electron mobilities tended to be low and inconsistent, partly because of the relatively poor-quality films on the ZnO electron transport layer. Overall, we have shown that solubilizing groups enable film solution-casting and can fine-tune the properties of these near-infrared aza-BODIPY derivatives.
Decoupling pH Dependence of Flat Band Potential in Aqueous Dye-Sensitized Electrodes
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Factors that Control the Direction of Excited-State Electron Transfer at Dye-Sensitized Oxide Interfaces
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Self-Assembled Chromophore–Catalyst Bilayer for Water Oxidation in a Dye-Sensitized Photoelectrosynthesis Cell
Not Available
Extending Infrared Emission via Energy Transfer in a CsPbI 3 –Cyanine Dye Hybrid
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Charge-Transfer Dynamics of Fluorescent Dye-Sensitized Electrodes under Applied Biases
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Signatures of Antisymmetric Vibrations in the Ultrafast Dynamics of Quadrupolar Dyes
Antisymmetric molecular vibrations are central to ultrafast, nonadiabatic photophysical and photochemical processes such as conical intersection dynamics, Herzberg–Teller couplings and, potentially, singlet fission. Direct spectroscopic identification of such vibrations is, however, challenging, since they are typically Raman inactive and affect optical transitions only weakly. Here, we report experimental signatures of vibronic couplings to a high-frequency antisymmetric vibration in the excited state dynamics of a quasi-quadrupolar molecule by ultrafast two-dimensional electronic spectroscopy (2DES). The early time, sub-50 fs 2DES maps reveal an asymmetric peak pattern with characteristic low-energy cross-peaks. We show that these peaks arise from stimulated emission transitions from an anharmonic, double-minimum excited state potential energy surface formed by vibronic coupling to a high-frequency antisymmetric mode. Simulations based on a phenomenological essential state model support the results. Our findings offer a new approach for identifying antisymmetric vibrations in ultrafast 2DES and track excited state wavepacket motion before relaxation washes out the spectra.