Plasmonic CsPbBr_(3)–Au nanocomposite for excitation wavelength dependent photocatalytic CO_(2) reduction

The optoelectronic performance of CsPbBr_3 nanocrystal(NC) has been dramatically limited by the severe charge carrier recombination and its narrow light absorption range,which are anticipated to be resolved via coupling with plasmonic Au nanoparticle(NP).In view of this,CsPbBr_3-Au nanocomposite is fabricated and further employed as a concept model to study the electronic interaction between perovskite NC and Au NP for the first time.It has been found that the excitation-wavelength dependent carrier transfer behavior exists in CsPbBr_3-Au nanocomposite.Upon illumination with visible light(λ>420 nm),photo-generated electrons in CsPbBr_3 can inject into Au with an electron injection rate and efficiency of 2.84×10~9 s^(-1) and 78%,respectively.The boosted charge separation is further translated into a 3.2-fold enhancement in CO_2 photocatalytic reduction activity compared with pristine CsPbBr_3.On the other hand,when solely exciting Au NP with longer wavelength light(λ>580 nm),the localized surface plasmon resonance(LSPR) induced hot electrons in Au NPs can transfer to CsPbBr_3 NC and further participate in photocatalytic reaction towards CO_2 reduction.The present study provides new insights into preparing plasmonic nanostructure to enhance the performance of perovskite based optoelectronic devices.

Layered-stacking of titania films for solar energy conversion:Toward tailored optical,electronic and photovoltaic performance

Nanostructured TiO_2 with differentiate morphologies has attracted tremendous attention due to its wide band-gap nature as well as outstanding optical and electric properties for solar-driven light-toelectricity conversion application. Layered-stacking TiO_2 film such as double-layer, tri-layer, quadrupleor quintuplicate-layer, is highly desirable to the design of high-performance semiconductor material photoanodes and the development of advanced photovoltaic devices. In this minireview, we will summarize the recent progress and achievements on proof-of-concept of layered-stacking TiO_2 films(LTFs) for solar cells with emphasis on the tailored properties and synergistic functionalization of LTFs, such as optimized sensitizer adsorption, broadened light confinement as well as facilitated electron transport characteristics.Various demonstrations of LTFs photovoltaic systems provide lots of possibilities and flexibilities for more efficient solar energy utilization that a wide variety of TiO_2 with distinguished morphologies can be integrated into differently structured photoanodes with synergistic and complementary advantages. This key structure engineering technology will also pave the way for the development of next generation state-ofthe-art electronics and optoelectronics. Finally, from our point of view, we conclude the future research interest and efforts for constructing more efficient LTFs as photoelectrode, which will be highly warranted to advance the solar energy conversion process.

Blade-coating Perovskite Films with Diverse Compositions for Efficient Photovoltaics

In this research highlight,recent significant advances with hot-assisted blade-coating or air knife-assisted blade-coating of different perovskite compositions with bandgaps ranging from 1.3 eV to 1.9 eV(i.e.widebandgap or small-bandgap perovskites with mixed cations and anions,2D/3D perovskites,Pb/Sn binary perovskites,and all-inorganic perovskites)for single-junction or tandem PSCs are discussed,with an emphasis on elucidating the distinct ink formulation engineering strategies,crystal growth mechanisms,crystallization kinetics,and optoelectronic properties of the different perovskite compositions.

构建三元WO_(3)/CsPbBr_(3)/ZIF-67异质结用于高效光催化CO_(2)还原

近年来,卤素钙钛矿纳米材料以其优异的光电性能在光催化等领域引起了关注.然而,光生载流子严重的复合反应和较差的反应动力学也极大地限制了其光催化性能.本论文设计合成了一种三元WO_(3)/CsPbBr_(3)/ZIF-67异质光催化剂,并将其应用于有效的CO_(2)光还原反应.研究表明,WO_(3)与CsPbBr_(3)之间构建的Z型电荷转移路径能够保证光生载流子的有效转移和分离.此外,在表面修饰具有活性Co中心的ZIF-67壳层作为助催化剂有利于改善复合材料的CO_(2)的吸附和活化能力.因此,电荷分离和CO_(2)吸附性能的增强大大提高了WO_(3)/CsPbBr_(3)/ZIF-67的光催化活性,还原产物中CO产率达到99.38μmol g_(−1),是单一CsPbBr_(3)的6.8倍.这项工作有望为开发高效的卤素钙钛矿基光催化剂及其在CO_(2)还原和其他复杂光催化反应中的应用提供参考.

A facile method to fabricate high-quality perovskite nanocrystals based on single crystal powder

Although great advancements have been successfully achieved in ligand-assisted reprecipitation strategy(LARP)towards lead halide perovskite nano crystals(NCs)syn thesis,it still remains challe nging to develop bright and stable iodide-based perovskite NC via facile LARP.Herein,striki ngly bright MAPbl3 NCs with photoluminesce nee qua ntum yield(PLQY)as high as 79%are synthesized via replacing the raw material(MAI and Pbh)with MAPbl3 crystal powder during LARP procedure.It has been found that crystal powder derived MAPbl3 NCs are more iodide-rich compared with that based on raw material,which is favorable to passivate the surface trap state.Accordingly,femtosecond transient absorption spectroscopies and space charge limited current measurements have corroborated that the trap density is much less in crystal powder resulted MAPbl3 NCs.Further analyses indicate stronger solvation with reduced precursor colloid size has been observed in crystal powder derived precursor solution probably due to the formation of MAPbl3-DMF.This work has provided a facile but valid method to enhance the photoluminesce nee of perovskite NC via modulati ng the beginning precursor solution.