Hairui Liu

Passivated perovskite crystallization and stability in organic–inorganic halide solar cells by doping a donor polymer

Photovoltaic performance of planar perovskite hybrid solar cells (pero-HSCs) has been improved by mixing CH3NH3PbIxCl3−x and an electron donor polymer [N-9′′-hepta-decanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiaz-ole)] (PCDTBT). PCDTBT contains lone pairs of electrons due to the presence of S and N atoms, which could passivate the trap states of the perovskite layer and thus reduce the number of film defects. A Stonehenge-like structure could be formed by the interaction of CH3NH3PbIxCl3−x and PCDTBT, developing more ordered orientation crystallization and a high quality film morphology. The doped solar cells are characterized by their excellent photovoltaic properties and enhanced stability. When the doping concentration is 0.3 mg mL−1, the fabricated solar cell device exhibits an outstanding power conversion efficiency (PCE) of 15.76%, which represents a significant improvement with respect to the magnitude of 16% obtained for the reference device.

Improving the stability of the perovskite solar cells by V2O5 modified transport layer film

This study describes a method for producing highly stable perovskite solar cells (PSCs). On the basis of conventional PSCs, a high-performance device was prepared using a vanadium pentoxide (V2O5) film to modify the poly(3,4-ethylene dioxy-thiophene)–poly(styrene sulfonate) (PEDOT:PSS) hole transport layer (HTL). The V2O5 modified layer prevents the acidic PEDOT:PSS film from etching the indium tin oxide (ITO) electrode and maintains the stability of the PSC structure. In addition, a 4,7-diphenyl-1,10-phenanthroline (Bphen) modified layer prevented the photoactive layer film from coming into direct contact with the Ag electrode to enhance the lifetime of the PSC stored in the air. In our study, a stable power conversion efficiency (PCE) of 15.49% was achieved using this method. Compared to the same type of devices, this type of device exhibited excellent performance and its stability was much higher than that of other device structures when stored in air. On modifying the transport layers to enhance the stability and longevity of the PSC, a method is provided for reference for further research.

Fabrication of In2O3/ZnO@Ag nanowire ternary composites with enhanced visible light photocatalytic activity

Herein, an In2O3/ZnO@Ag ternary photocatalyst was synthesized by a facile co-precipitation process. The results indicated that Ag nanowires were encapsulated by In2O3/ZnO compounds, and the obtained In2O3/ZnO@Ag photocatalyst showed strong absorption in the visible light region. The photoluminescence (PL) emission intensity gradually decreased for In2O3/ZnO@Ag as compared to that for the In2O3/ZnO composites and pure ZnO. The as-prepared In2O3/ZnO@Ag composites exhibited excellent visible light photocatalytic activities for degradation of organic contaminants (methyl orange and 4-nitrophenol). The enhancement of photocatalytic activity was ascribed to the extended visible light absorption region by Ag nanowires and the formation of close hetero-structure by the matched band structures of In2O3 and ZnO. Finally, a possible photocatalytic mechanism was proposed based on the matched energy band structure and active species trapping experiments.

Efficient and stable perovskite solar cells based on high-quality CH3NH3PbI3−xClx films modified by V2Ox additives

The method of preparing perovskite films in ambient air is of great importance to commercializing high-performance planar perovskite solar cells (PSCs). Herein, an efficient and stable inverted planar PSC has been prepared via a simple solution method in ambient air. A suitable vanadium oxide (V2Ox) aqueous solution is mixed with a CH3NH3PbI3−xClx precursor solution, resulting in an improvement in the CH3NH3PbI3−xClx film. Perovskite films with large crystal sizes could be obtained using V2Ox additives. The improvement in the performance of perovskite films is conducive to the separation and transmission of charge carriers. For PSCs, the highest power conversion efficiency (PCE) of 16.14% was obtained by controlling the proportion of V2Ox additives in ambient air. It is via a physical mechanism that V2Ox particles are dispersed in the perovskite crystal boundary, and the heterogeneous structure between CH3NH3PbI3−xClx and V2Ox is formed. In addition, the slow migration of iodide ions and stability of the perovskite films are also achieved. What merits more attention is that the PSCs with CH3NH3PbIxCl3−x:V2Ox (2.5 wt%) still maintain a high PCE after being stored for 1000 h, more than 70% of the initial one.

Direct Growth of Feather-Like ZnO Structures by a Facile Solution Technique for Photo-Detecting Application

The feather-like hierarchical zinc oxide (ZnO) was synthesized via successive ionic layer adsorption and reaction without any seed layer or metal catalyst. A possible growth mechanism is proposed to explain the forming process of ZnO feather-like structures. Meanwhile, the photo-electronic performances of the feather-like ZnO have been investigated with the UV-vis-NIR spectroscopy, I-V and I-tmeasurements. The results indicate that feather-like ZnO hierarchical structures have good anti-reflection and excellent photo-sensitivity. All results suggest that the direct growth processing of novel feather-like ZnO is envisaged to have promising application in the field of photo-detector devices.