The hierarchical heterostructure of NiMoO4@NiMnCo2O4 (NMO@NMCO) with furry structures of NMCO juxtaposed with NMO nanowires are endowed with multiple electrochemically active and accessible sites for ion storage, thus delivering an ultrahigh specific capacitance of 2706 F g–1, nearly two-fold times greater than that of sole NMCO. Electrodeposition of an overlayer of a highly robust and electrically conducting polymer, poly­(3,4-propylenedioxythiophene) (PProDOT), not only improves the energy storage performance but also assists the binary oxide cathode in retaining its structural integrity during redox cycling. Coupling with an anode of porous flaky carbon (FC) derived from groundnut shells results in an asymmetric supercapacitor of FC//PProDOT@NiMoO4@NiMnCo2O4, which delivers an outstanding capacitance of 552 F g–1, energy and power density ranges of 172–40 Wh kg–1 and 0.75–10 kW kg–1, respectively, and a remarkable cycle life of 50 000 cycles, with ∼97.8% capacitance retention, over an operational voltage window of 1.5 V. From an application perspective, the charged supercapacitor was connected to a complementary coloring reversible electrochromic device (ECD) of Prussian blue//PProDOT, and the ECD state transformed from a pale-blue to a deep blue hue, thus signaling the efficient utilization of energy stored in the supercapacitor. The energy-saving attribute of the ECD was realized in terms of an integrated visible-light modulation of 39% that accompanied the optical transition. Deployment of low-cost devices at homes and commercial spaces, capable of storing and saving energy, is the way forward, and this is one significant step in this direction.

Selenium nanoparticle-decorated silicon nanowire (Se NPs@Si NWs) electrodes are applied as a photoanode in a liquid-junction photoelectrochemical (PEC) solar cell for the first time. Upon illumination, the Se NPs anchored along the axial length of Si NWs allow fast hole extraction at the radial Se/Si junctions because of the p-type conduction nature of Se NPs, thus enhancing electron–hole separation and simultaneously increasing the population of photoexcited electrons in Si NWs through light scattering that amplifies the effective light absorption of Si NWs. These attributes of Se NPs result in a power conversion efficiency (PCE) of 7.03% for the Se NPs@Si NW-based liquid-junction solar cell encompassing a Br–/Br2 electrolyte and a carbon fabric counter electrode. This PCE is greater by 43% than that of the analogous Si NW-based cell. Se NPs are photoconducting because of facile hole propagation that occurs particularly along the c-axis of trigonal Se NPs with a hexagonal crystal structure and size effects improve the optical path length, factors that lead to a significantly improved performance. Compared to Pt or Au NPs that have been explored previously in combination with Si NWs, where their roles are distinctively different, Se NPs here are not only more cost effective and easy to be synthesized on a large scale but also enable an improvement in PCE of Si NWs by relying on unique mechanisms. Optical, structural, PEC, and impedance studies furnish a deep understanding of the phenomena involved in yielding a superior performing liquid-junction PEC solar cell based on the Se NPs@Si NW photoanode.

Silicon nanowire (SiNW) arrays offer a range of exciting opportunities, from maximizing solar spectrum utilization for high-performance liquid-junction solar cells (LJSCs) to functioning as potential micro-supercapacitors in the near future. This work, contrasting strongly with the previously reported studies on SiNW-based LJSCs where electron-conducting nanoparticles of Pt or Au were employed to achieve high efficiencies, aims at tethering relatively inexpensive, hole-conducting, and photoresponsive carbon-coated tellurium nanorods (C@TeNRs) to SiNWs in the quest to achieve an outstanding solar cell performance. A SiNW LJSC (control cell) with a SiNWs/Br–, Br2/carbon-fabric architecture delivers a power conversion efficiency (PCE) of 4.8%. Further, by anchoring C@TeNRs, along the lengths of SiNWs via electrophoresis, a PCE of ∼11.6% is attained for a C@TeNRs@SiNWs/Br–, Br2/carbon-fabric-based LJSC. The multifunctionality of C@Te comes to the fore in this cell where (1) the p-type (hole) conducting nature of C@Te ensures efficient charge separation by rapidly collecting holes from SiNWs (and suppresses recombination), (2) the C@TeNRs are also photoresponsive and increase light-harvesting, and (3) the C coating restricts the chemical corrosion and photo-oxidation of SiNWs and the Te core by the acidic electrolyte, thereby improving the cell’s operational lifetime. This LJSC also serves as an effective stand-alone energy-storage device giving an improved areal specific capacitance of 1605 μF cm–2 (at 1 mA cm–2). This study unravels the pivotal role played by C@TeNRs in controlling the performance of SiNW-based LJSCs.

We report the synthesis of single crystals of the quaternary sulfide, BaCeCuS3, for the first time by heating a polycrystalline sample of BaCeCuS3 with an excess of KCl flux inside...

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