Y.L. Zhao

Influence of annealing temperature on performance of dye-sensitized TiO2 nanorod solar cells

Single-crystal rutile TiO2 nanorod (NR) arrays have been synthesized on the fluorine-doped tin oxide substrates, followed by an annealing at 200–600xa0°C. It is found that DSSCs fabricated using TiO2 NR arrays which undergo annealing display an increased efficiency than those that do not undergo annealing. The optimal efficiency of 4.42% power conversion is achieved in the DSSC made with 500xa0°C annealed arrays, which show a 450% increase in the overall conversion efficiency. The improvement is ascribed to the increased light harvesting, the enhanced electric contact and the suppressed recombination of the injected electrons with redox species in the electrolyte.

Improved performance of perovskite solar cell by controlling CH3NH3PbI3−xClx film morphology with CH3NH3Cl-assisted method

Sequential deposition solution-based method has been widely used for the fabrication of perovskite solar cells (PSCs). However, there is still a challenge to achieve homogeneous and consecutive surface of the perovskite layers. In this work, CH3NH3PbI3−xClx layers were prepared by a modified two-step solution method. Specifically, the optimum amount of CH3NH3Cl pre-added into PbI2 precursor solution, the appropriate size of pinholes and voids appear in PbI2 films and leave room for the growth of CH3NH3PbI3−xClx crystal. Under this condition, the crystal grains size is diminished and the surface coverage ratio of CH3NH3PbI3−xClx film is enhanced, which prevent the combination of electron-hole pairs on the interface between perovskite layer and TiO2 substrate. By varying the CH3NH3Cl amounts, the PSC devices displayed the highest power conversion efficiency of 13xa0%, which was obviously higher than that of the one prepared via transitional routes (10.32xa0%). As a result, we developed a simple and repeatable route for controllable synthesis of perovskite absorption layers, which is demonstrated to be effective to improve the performance of PSCs.

CNT–G–TiO2 layer as a bridge linking TiO2 nanotube arrays and substrates for efficient dye-sensitized solar cells

This study incorporated a 3-D hybrid material comprising graphene and carbon nanotubes (CNTs) into a TiO2 composite paste to adhere TiO2 nanotube arrays (NTAs) as photoanodes. The effect of the proportion of CNTs to graphene on the dye-adsorption ability of bonding layers was investigated and the optimal proportion of 2:1 provided a greatest degree of dye absorption. The DSSC efficiencies firstly increased and then decreased with increasing amount of CNT–G hybrid. The optimized DSSC efficiency of 6.17% was achieved at a suitable concentration (0.1 wt%) of CNT–G, which is due to a balance between electron transport and light harvesting in the photoanode.

Photoelectrochemical performance and biosensor application for glutathione (GSH) of W-doped BiVO 4 thin films

Tungsten-doped BiVO4 (W:BiVO4) thin films were deposited on the FTO glass through a spin-coating method and their photoelectrochemical (PEC) properties were investigated. Although W-doping does not significantly affect the morphology, structure and light harvesting a suitable W-doping treatment can enhance the PEC activity of BiVO4 thin films, leading to a 100% enhancement of the photocurrent. It is found that the doping of 10xa0at.% W leads to an increased photocurrent from 0.75 mAxa0cm−2 (for undoped) to 1.5 mAxa0cm−2. Moreover, through an electrochemical impedance analysis, the enhancement of PEC performance was mainly due to the enhanced n-type conductivity of BiVO4 and charge separation at the solid/liquid interface. A scheme model was proposed to clarify the reason for performance enhancement. Moreover, a PEC biosensor was fabricated for detecting the glutathione, leading to an excellent detect limit of 96xa0nM.

Enhanced photoelectrochemical performance by doping Mo into BiVO4 lattice

The Mo-doped BiVO4 (m-BiVO4) thin films were deposited onto transparent conducting substrates via a facile metallic organic deposition method. The effect of nominal Mo doping contents on the photoelectrochemical (PEC) performance was investigated. By terms of the electrochemical impedance spectra and Mott–Schottky results, the best PEC performance appeared in the 5 and 10 at% Mo-doped BiVO4 samples was attributed to a lowering of charge transfer resistance occurred at the electrode/electrolyte interface. Moreover, a self-powered Mo:BiVO4 PEC biosensor was fabricated for detecting the glutathione (GSH), which demonstrated a rapid response, a wide detection range 5–1000xa0µmol/L (µM), a ultralow detect limit of 59xa0nM, and a sensitivity of 835xa0A/cm2/mM−1.