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An investigation is conducted on the mechanism by which the absorbent chenodeoxycholate, cografted with a sensitizer onto Tio(sub 2) nanocrystals, alters the open-circuit photovoltage and short-circuit current of dye-sensitized solar cells. Absorbed molecules improve the cell performance by inducing band-edge movement and shielding of recombination centers by the organic molecules is the explanation given for the observed effects.

Effect of lithium intercalation on the transport dynamics and recombination kinetics in dye-sensitized solar cells at lithium densities below 5 atom% is presented. Results show that lithium insertion occurs under the normal operating conditions of a cell containing a lithium electrolyte.

The light harvesting efficiency of dye-sensitized photoelectrodes was enhanced, by coupling a TiO2 photonic crystal layer to a conventional film of TiO2 nanoparticles. The inverse opal photonic crystal caused a significant change in dye absorbance, which depended on the position of the stop band.

Living organisms use fractal structures to optimize material and energy transport across regions of differing size scales. Here we test the effect of fractal silver electrodes on light distribution and charge collection in organic semiconducting polymer films made of P3HT and PCBM. The semiconducting polymers were deposited onto electrochemically grown fractal silver structures (5000 nm × 500 nm; fractal dimension of 1.71) with PEDOT:PSS as hole-selective interlayer. The fractal silver electrodes appear black due to increased horizontal light scattering, which is shown to improve light absorption in the polymer. According to surface photovoltage spectroscopy, fractal silver electrodes outperform the flat electrodes when the BHJ film thickness is large (>400 nm, 0.4 V photovoltage). Photocurrents of up to 200 microamperes cm-2 are generated from the bulk heterojunction (BHJ) photoelectrodes under 435 nm LED (10 -- 20 mW cm-2) illumination in acetonitrile solution containing 0.005 M ferrocenium hexafluorophosphate as the electron acceptor. The low IPCE values (0.3 -- 0.7%) are due to slow electron transfer to ferrocenium ion and due to shunting along the large metal -- polymer interface. Overall, this work provides an initial assessment of the potential of fractal electrodes for organic photovoltaic cells. [ABSTRACT FROM AUTHOR]

Presents a report on the development of a photo-assisted electrochemical etching technique to fabricate macropores in single-crystalline gallium phosphide (GaP) with variable porosity. Confirmation from scanning electron microscopy and x-ray diffraction experiments that the material consists of three-dimensional, interconnected random networks; Use of optical transmission measurements to demonstrate that the nonabsorbing disordered structures scatter light; Other information.

2D materials, particularly transition metal dichalcogenides (TMDCs), have shown great potential for microelectronics and optoelectronics. However, a major challenge in commercializing these materials is the inability to control their doping at a wafer scale with high spatial fidelity. Interface chemistry is used with the underlying substrate oxide and concomitant exposure to visible light in ambient conditions for photo-dedoping wafer scale MoS 2 . It is hypothesized that the oxide layer traps photoexcited holes, leaving behind long-lived electrons that become available for surface reactions with ambient air at sulfur vacancies (defect sites) resulting in dedoping. Additionally, high fidelity spatial control is showcased over the dedoping process, by laser writing, and fine control achieved over the degree of doping by modulating the illumination time and power density. This localized change in MoS 2 doping density is very stable (at least 7 days) and robust to processing conditions like high temperature and vacuum. The scalability and ease of implementation of this approach can address one of the major issues preventing the "Lab to Fab" transition of 2D materials and facilitate its seamless integration for commercial applications in multi-logic devices, inverters, and other optoelectronic devices., (© 2024 The Author(s). Advanced Materials published by Wiley‐VCH GmbH.)