An electron transport layer is essential for effective operation of planar perovskite solar cells. In this Article, PW12-TiO2 composite was used as the electron transport layer for the planar perovskite solar cell in the device structure of fluorine-doped tin oxide (FTO)-glass/PW12-TiO2/perovskite/spiro-OMeTAD/Au. A proper downward shift of the conduction band minimum (CBM) enhanced electron extraction from the perovskite layer to the PW12-TiO2 composite layer. Consequently, the common hysteresis effect in TiO2-based planar perovskite solar cells was significantly reduced and the open circuit voltage was greatly increased to about 1.1 V. Perovskite solar cells using the PW12-TiO2 compact layer showed an efficiency of 15.45%. This work can contribute to the studies on the electron transport layer and interface engineering for the further development of perovskite solar cells.

In this study, Bi2S3 sensitive layer has been grown on the surface of WO3 nanoplate arrays via an in situ approach. The characterization of samples were carried out using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and ultraviolet–visible absorption spectroscopy (UV-vis). The results show that the Bi2S3 layer is uniformly formed on the surface of WO3 nanoplates and less interfacial defects were observed in the interface between the Bi2S3 and WO3. More importantly, the Bi2S3/WO3 films as photoanodes for photoelectrochemical (PEC) cells display the enhanced PEC performance compared with the Bi2S3/WO3 films prepared by a sequential ionic layer adsorption reaction (SILAR) method. In order to understand the reason for the enhanced PEC properties, the electron transport properties of the photoelectrodes were studied by using the transient photocurrent spectroscopy and intensity modulated photocurrent spectroscopy (IMPS). The Bi2S3/WO3 films prepared via an in situ approach have a greater transient time constant and higher electron transit rate. This is most likely due to less interfacial defects for the Bi2S3/WO3 films prepared via an in situ approach, resulting in a lower resistance and faster carrier transport in the interface between WO3 and Bi2S3.

Zn x Bi2S3+x sensitized platelike WO3 photoelectrodes on FTO substrates were for the first time prepared via a sequential ionic layer adsorption reaction (SILAR) process. The samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet visible spectrometry (UV–vis), and Raman spectra. The results show that the Zn x Bi2S3+x quantum dots (QDs) are uniformly coated on the entire surface of WO3 plates, forming a WO3/Zn x Bi2S3+x core/shell structure. The Zn x Bi2S3+x /WO3 films show a superior ability to capture visible light. High-efficiency photoelectrochemical (PEC) hydrogen generation is demonstrated using the prepared electrodes as photoanodes in a typical three-electrode electrochemical cell. Compared to the Bi2S3/WO3 photoelectrodes, the Zn x Bi2S3+x /WO3 photoelectrodes exhibit good photostability and excellent PEC activity, and the photocurrent density is up to 7.0 mA cm–2 at −0.1 V versus Ag/AgCl under visible light illumination. Investigation of the electron transport properties of the photoelectrodes shows that the introduction of ZnS enhances the photoelectrons’ transport rate in the photoelectrode. The high PEC activity demonstrates the potential of the Zn x Bi2S3+x /WO3 film as an efficient photoelectrode for hydrogen generation.

No abstract

In this paper, a novel Bi 2 S 3 /BiVO 4 heterojunction film was prepared by a facile drop-casting and hydrothermal method for the first time. The as-prepared films were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM) and ultraviolet visible spectrometry (UV-Vis). Interestingly, the heterojunction film was formed by epitaxial growth of Bi 2 S 3 nanowires on BiVO 4 nanostructures and exhibited a good visible light absorption performance. The photoelectrochemical (PEC) hydrogen generation was demonstrated using the prepared films as photoanodes.The heterojunction photoelectrode showed an excellent PEC activity and generated a photocurrent density of 7.81 mA cm -2 at 0.9761 V vs. RHE (0.1 V vs.Ag/AgCl) in the electrolyte solution containing 0.35 M Na 2 SO 3 and 0.25 M Na 2 S.The present study provides new insight into the design of highly efficient heterojunction photoelectrode for hydrogen generation.of Bi 2 S 3 can extend the spectral responsive range and the formation of heterojunction can promote the separation of photogenerated carriers.