A carbon doped anatase TiO2 as a promising semiconducting layer in Ru-dyes based dye-sensitized solar cells

Analysis of Hybrid Hetero-Homo Junction Lead-Free Perovskite Solar Cells by SCAPS Simulator

In this work, we report on the effect of substituting the active intrinsic i-layer on a conventional pin structure of lead-free perovskite solar cell (PSC) by a homo p-n junction, keeping the thickness of the active layer constant. It is expected that when the active i-layer is substituted by a p-n homo junction, one can increase the collection efficiency of the photo-generated electrons and holes due to the built-in electric field of the homo junction. The impact of the technological and physical device parameters on the performance parameters of the solar cell have been worked out. It was found that p-side thickness must be wider than the n-side, while its acceptor concentration should be slightly lower than the donor concentration of the n-side to achieve maximum efficiency. In addition, different absorber types, namely, i-absorber, n-absorber and p-absorber, are compared to the proposed pn-absorber, showing a performance-boosting effect when using the latter. Moreover, the proposed structure is made without a hole transport layer (HTL) to avoid the organic issues of the HTL materials. The back metal work function, bulk trap density and ETL material are optimized for best performance of the HTL-free structure, giving Jsc = 26.48, Voc = 0.948 V, FF = 77.20 and PCE = 19.37% for AM1.5 solar spectra. Such results highlight the prospective of the proposed structure and emphasize the importance of using HTL-free solar cells without deteriorating the efficiency. The solar cell is investigated by using SCAPS simulator.

Carbon Black-Doped Anatase TiO2 Nanorods for Solar Light-Induced Photocatalytic Degradation of Methylene Blue

In this work, C-doped TiO₂ nanorods were synthesized through doping carbon black into hydrothermally synthesized solid-state TiO₂ nanowires (NWs) via calcination. The effects of carbon content on the morphology, phase structure, crystal structure, and photocatalytic property under both UV and solar light by the degradation of methylene blue (MB) were explored. Besides, the photoelectrochemical property of C-TiO₂ was systematically studied to illustrate the solar light degradation mechanism. After doping with C, TiO₂ NWs were reduced into nanorods and the surface became rough with dispersed particles. Results showed that C has successfully entered the TiO₂ lattice, resulting in the lattice distortion, reduction of band gap, and the formation of C-Ti-O, which expands TiO₂ to solar light activation. Comparing with P25 and anatase TiO₂ NWs, doping with carbon black showed much higher UV light and solar light photocatalytic activity. The photocatalytic activity was characterized via the degradation of MB, showing that K _ap was 0.0328 min^-1 under solar light, while 0.1634 min^-1 under UV irradiation. The main free radicals involved in methylene blue degradation are H⁺ and OH^•-. Doping with carbon black led to the reduction of photocurrent in a long-term operation, while C-doping reduced the electron-hole recombination and enhanced the carrier migration.

Improving the efficiency of copper-dye-sensitized solar cells by manipulating the electrolyte solution

The use of a copper(i) dye, bearing a 2,9-dimesityl-1,10-phenanthroline and a 6,6'-dimethyl-2,2'-bipyridine-4,4'-dibenzoic acid, was investigated in DSSCs with various electrolyte solutions based on two different redox mediators, namely the common I-/I3- couple and an interesting copper electron shuttle. The experimental results provide evidence of the importance of the redox mediator concentration and the crucial role of additives such as 4-tert-butylpyridine and lithium bis(trifluoromethanesulfonyl)imide in the performance of sustainable "full-copper" DSSCs, consolidating the way to DSSCs with Earth-abundant components.