Xueqi Zhang

High-Efficiency AgInS2-Modified ZnO Nanotube Array Photoelectrodes for All-Solid-State Hybrid Solar Cells

Highly ordered AgInS2-modified ZnO nanoarrays were fabricated via a low-cost hydrothermal chemical method, and their application as all-solid-state solar cells was also tested. A sensitizer and a buffer layer were developed around the surface of ZnO nanotubes in the preparation process, and this method is easily be manipulated to produce uniform structure. In this structure, the ZnO served as direct electron transport path, the ZnS as the buffer layer, and the ternary sensitizer AgInS2 as absorber and outer shell. The novel all-solid-state hybrid solar cells (ITO/ZnO/ZnS/AgInS2/P3HT/Pt) showed improved short-circuit current density (Jsc) of 7.5 mA/cm(2), open-circuit voltage (Voc) of 512 mV, giving rise to a power conversion efficiency of 2.11%, which is the relatively highest value ever reported for ZnO-based all-solid-state hybrid solar cells. This better result is attributed to the improved absorption spectrum, high speed of photoinduced charge transmission velocity, and appropriate gradient energy gap structure, which implies a promising application in all-solid-state solar cells.

Trilaminar ZnO/ZnS/Sb2S3 nanotube arrays for efficient inorganic–organic hybrid solar cells

Efficient hybrid solid-state solar cells based on novel trilaminar ZnO/ZnS/Sb2S3 nanotube arrays (NTs) and poly(3-hexylthiophene) (P3HT) are fabricated by using a buffer layer using ZnS and surface modification using a sensitizer layer (Sb2S3). Vertically aligned trilaminar ZnO/ZnS/Sb2S3 nanotube arrays (NTs) were directly grown on an indium-doped tin oxide (ITO) substrate via a low-cost hydrothermal chemical conversion method based on ion exchange, which is easy to be manipulated and can form uniform structures without destroying the original morphology. The ZnO/ZnS/Sb2S3/P3HT hybrid solar cell exhibited an improved short-circuit current density (Jsc) of 5.57 mA cm−2, open-circuit voltage (Voc) of 440 mV, giving rise to a power conversion efficiency of 1.32%. The trilaminar architecture is able to suppress carrier recombination and increase electron collection efficiency via (i) increasing photon absorption through a sensitizer layer (Sb2S3), (ii) forming a buffer layer (ZnS) on the surface of ZnO NTs in the chemical conversion process and (iii) a better energy level alignment in the ZnO/ZnS/Sb2S3/P3HT.

Preparation and enhanced photoelectrochemical performance of selenite-sensitized zinc oxide core/shell composite structure

A fast, versatile and low-cost hydrothermal chemical synthesis based on ion-exchange has been used to deposit a shell of cupric selenite onto vertically aligned zinc oxide nanorod arrays with a buffer layer of zinc selenite for photoelectrochemical water splitting. In the present work, detailed growth mechanisms for single shell of zinc selenite composite structure and double shells of zinc selenite and cupric selenite closed nanotubes based on zinc oxide core are discussed. The enhanced optical property and the improved photoelectrochemical performance are characterized. On the basis of cupric selenite outer shell, such a novel core/shell nanostructure provides a high photocatalytic activity, and the photocurrent density is up to 5.70 mA cm−2. This promising result is probably due to the improved absorption efficiency, enhanced photoelectron collection process and reduced recombination rate including photoelectron injection and charge transportation. The double shells based on zinc oxide composite structure can render this new material promising in photoelectrochemical water splitting.

Three-dimensional flower-like hybrid BiOI–zeolite composites with highly efficient adsorption and visible light photocatalytic activity

Three-dimensional flower-like hybrid BiOI–zeolite composites were synthesized via a simple, facile and environmentally-benign hydrothermal method. And the synthetic mechanism of the flower-like BiOI–zeolite hierarchical structures was discussed. The as-obtained BiOI–zeolite samples exhibited excellent performance in the degradation of methylene blue solution under visible light irradiation. The influence of different Bi/I molar ratios and surfactants was studied. The degradation rate of MB by BiOI–zeolite composite photocatalysts can reach 94.8% under visible light irradiation for 10 min, when the Bi/I molar ratio is 1:1 and is surfactant free. This implies its huge application potential as photocatalysts in degradation of pollutants under visible light.

Flower‐like Cu2In2ZnS5 Nanosheets: A Novel Promising Photoelectrode for Water Splitting

This paper describes a promising photoelectrochemical electrode based on a flower‐like Cu2In2ZnS5 structure composed of nanosheets and its use as a photoelectrode for photoelectrochemical (PEC) water splitting for the first time. The detailed growth of Cu2In2ZnS5 was discussed. The morphology and microstructure were characterized in detail. PEC measurements showed that on the basis of the optimal hydrothermal time, flower‐like Cu2In2ZnS5 exhibited high photoelectrochemical activity, as the photocurrent density reached up to 2.00 mA cm−2. The remarkable PEC performance stems from crucial factors, including improved light absorption, an ideal band gap value, decoupling of the directions of light absorption and charge‐carrier collection, and large surface area. Our results indicate that the flower‐like Cu2In2ZnS5 structure composed of nanosheets has enormous potential in PEC water splitting.