Pro-tRNA synthetase from Phaseolus aureus and Delonix regia

Pro-tRNA synthetase from Phaseolus aureus was photoinactivated in the presence of methylene blue or rose bengal. Pro and several imino acid analogues protected the enzyme against dye-mediated photoinactivation but ATP was ineffective. Together with kinetic data, this evidence suggested that a His-residue near the Pro-binding site was involved in the enzyme reaction. In the absence of methylene blue, Phaseolus enzyme was stable to light whilst that from Delonix was rapidly and reversibly photoinactivated. ATP as well as Pro, protected the Delonix enzyme against dye-independent photoinactivation. In the presence of methylene blue, the Delonix enzyme was more rapidly photoinactivated than in the absence of the dye. p-Chloromercuribenzoate (pCMB)-inhibited enzyme from both Phaseolus and Delonix was reactivated by sulphydryl reducing reagents. Reactivation of Delonix enzyme was markedly temperature-dependent whilst Phaseolus enzyme was reactivated equally efficiently at all temperatures tested. ATP, tRNA, Pro and several analogues of Pro, protected both the Phaseolus and Delonix enzymes against pCMB inhibition. The possible roles of the His-residue and SH group are discussed in relation to the known differences in substrate specificity between the Phaseolus and Delonix enzymes.     

Nitrogen‐Doped CNx/CNTs Heteroelectrocatalysts for Highly Efficient Dye‐Sensitized Solar Cells

The use of polydopamine as a nitrogen containing precursor to generate catalytically active nitrogen‐doped carbon (CN_x) materials on carbon nanotubes (CNTs) is reported. These N‐doped CN_x/CNT materials display excellent electrocatalytic activity toward the reduction of triiodide electrolyte in dye‐sensitized solar cells (DSSCs). Further, the influence of various synthesis parameters on the catalytic performance of CN_x/CNTs is investigated in detail. The best performing device fabricated with the CN_x/CNTs material delivers power conversion efficiency of 7.3%, which is comparable or slightly higher than that of Pt (7.1%) counter electrode‐based DSSC. These CN_x/CNTs materials show great potential to address the issues associated with the Pt electrocatalyst including the high cost and scarcity.     

MoS2‐Based All‐Purpose Fibrous Electrode and Self‐Powering Energy Fiber for Efficient Energy Harvesting and Storage

Here an all‐purpose fibrous electrode based on MoS₂ is demonstrated, which can be employed for versatile energy harvesting and storage applications. In this coaxial electrode, ultrathin MoS₂ nanofilms are grown on TiO₂ nanoparticles coated carbon fiber. The high electrochemical activity of MoS₂ and good conductivity of carbon fiber synergistically lead to the remarkable performances of this novel composite electrode in fibrous dye‐sensitized solar cells (showing a record‐breaking conversion efficiency of 9.5%) and high‐capacity fibrous supercapacitors. Furthermore, a self‐powering energy fiber is fabricated by combining a fibrous dye‐sensitized solar cell and a fibrous supercapacitor into a single device, showing very fast charging capability (charging in 7 s under AM1.5G solar illumination) and an overall photochemical‐electricity energy conversion efficiency as high as 1.8%. In addition, this wire‐shaped electrode can also be used for fibrous Li‐ion batteries and electrocatalytic hydrogen evolution reactions. These applications indicate that the MoS₂‐based all‐purpose fibrous electrode has great potential for the construction of high‐performance flexible and wearable energy devices.     

A Hierarchically Organized Photoelectrode Architecture for Highly Efficient CdS/CdSe‐Sensitized Solar Cells

A form of photoelectrode architecture suitable for inorganic semiconductor solar cells is reported. The developed architecture consists of hierarchically organized TiO₂ nanostructures with several tens of nanometer‐sized particles that have a large surface area and open channels with several hundred‐nanometer‐gaps perpendicular to the substrate. These are tailored by controlling the kinetic energy of the ablated species during pulsed laser deposition (PLD). To fabricate the solar cells, CdS and CdSe inorganic sensitizers are assembled onto the architecture by successive ionic layer adsorption and reaction and polysulfide solution is used as an electrolyte with lead sulfide counter‐electrodes. The inorganic semiconductor solar cells using the developed architecture (PLD‐TiO₂) show high energy conversion efficiencies of 5.57% compared to a conventional mesoporous TiO₂ film(NP‐TiO₂) (3.84%) with an optical mask at 1 sun of illumination. The improved cell performance of PLD‐TiO₂ is attributed to greater light‐harvesting ability, which results in the enhancement of the J_sc value. PLD‐TiO₂ absorbs more CdS/CdSe because of its larger surface area and excellent adhesion properties with fluorine‐doped tin oxide (FTO) substrates. Additionally, due to its unique channel‐shaped architecture, PLD‐TiO₂ has a longer electron lifetime compared to NP‐TiO₂.     

High‐Performance,Transparent, Dye‐Sensitized Solar Cells for See‐Through Photovoltaic Windows

Dye‐sensitized solar cells (DSCs) have attracted great interest as one of the most promising photovoltaic technologies, and transparent DSCs show potential applications as photovoltaic windows. However, the competition between light absorption for photocurrent generation and light transmittance for obtaining high transparency limits the performance of transparent DSCs. Here, transparent DSCs exhibiting a high light transmittance of 60.3% and high energy conversion efficiency (3.66%) are reported. The strategy is to create a cocktail system composed of ultraviolet and near‐infrared dye sensitizers that selectively and efficiently harvest light in the invisible or low‐eye‐sensitivity region while transmitting light in high‐eye‐sensitivity regions. This new design provides a reasonable approach for realizing high efficiency and transparency DSCs that have potential applications as photovoltaic windows.     

Design of a New Energy‐Harvesting Electrochromic Window Based on an Organic Polymeric Dye,a Cobalt Couple,and PProDOT‐Me2

A new design for an energy‐harvesting electrochromic window (EH‐ECW) based on the fusion of two technologies, organic electrochromic windows and dye‐sensitized solar cells (DSSCs), is presented. Unlike other power‐generating smart windows, such as photoelectrochromic devices that are passive and only contain two states (i.e., a closed‐circuit colored state and an open‐circuit bleaching state), EH‐ECW allows active tuning of the transmittance by varying the applied potential and it functions as a photovoltaic cell based on a DSSC. The resulting device demonstrates a fast switching rate of 1 s in both the bleaching and coloring processes through the use of an electrochromic polymer as a counter electrode layer. To increase the transmittance of the device, a cobalt redox couple and a light‐colored, yet efficient, organic dye are used. The organic dye contains a polymeric structure that contributes to the high cyclic stability. The device exhibits a power conversion efficiency (PCE) of 4.5% (100 mW cm^‐2) under AM 1.5 irradiation, a change in transmittance of 34% upon applied potential, and shows only 3% degradation in the PCE after 5000 cycles.