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Construction, photoelectric response and phase transition for new hybrid double perovskites showing narrow band gaps

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Chinese Chemical Letters 2023年第4期34卷 595-600页

作者： Changyuan Su Zhixu Zhang Jie Yao Ming Chen Peizhi Huang Yi Zhang Dawei Fu Liyan Xie Ordered Matter Science Research Center Jiangsu Key Laboratory for Science and Applications of Molecular FerroelectricsSoutheast UniversityNanjing 211189China Institute for Science and Applications of Molecular Ferroelectrics Key Laboratory of the Ministry of Education for Advanced Catalysis MaterialsZhejiang Normal UniversityJinhua 321004China Chaotic Matter Science Research Center Department of MaterialsMetallurgy and ChemistryJiangxi University of Science and TechnologyGanzhou 341000China

To explore the lead-free key scientific issue in perovskite, double perovskite based on Ag Bi and Cu Bi was naturally selected as a competitive candidate due to its fascinating functional features, such as self-powered circularly polarized light detection, X-ray detection, photoluminescence and so on. However, the most challenging point is to simulate the structure and function of traditional lead-based perovskite in new double perovskite. At the same time, there are few suitable double perovskite systems with optical and electrical potential. The above two points greatly limit the competitiveness of double perovskite. In order to solve this problem, firstly, by analyzing and comparing previous studies,we used 2,2-dimethylpropan-1-aminium(abbreviated as 2,2-DPA) as the organic template to assemble materials. Solid-to-solid phase transition materials(2,2-DPA)3Bi2I91 and(2,2-DPA)3Pb2I72 were constructed. Along the path of lead-free and two-dimensional maintenance, we successfully synthesized(2,2-DPA)4AgBiI8.H_(2)O 3 and(2,2-DPA)_(4)CuBiI8.H_(2)O 4. As two typical semiconductors, 3 and 4 with narrower optical band gaps of 1.98 and 1.76 e V show obvious photo-response when the xenon lamp with intensity of 20 m W/cm^(2)is on or off, implying that they may be applied to light-harvesting and light-detecting devices. By referring to the phase transition mechanism of 1 and 2, 3 may be caused by ordered-disordered transition of the organic part, which was proven to be the first solid-to-solid phase transition material with -oriented layered double perovskites with n = 1 by systematic characterization methods after dehydration for all we know. We believed that this work can provide meaningful guidance for the development of lead-free double perovskites.

关键词： Double perovskite photoelectric response Phase transition Dielectric properties Semiconducting behavior

Band alignment of type-Ⅰ SnS_(2)/Bi_(2)Se_(3) and type-Ⅱ SnS_(2)/Bi_(2)Te_(3) van der Waals heterostructures for highly enhanced photoelectric responses

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Science China Materials 2022年第4期65卷 1000-1011页

作者： Mingwei Luo Chunhui Lu Yuqi Liu Taotao Han Yanqing Ge Yixuan Zhou Xinlong Xu Shaanxi Joint Lab of Graphene State Key Laboratory of Photon-Technology in Western China EnergyInternational Collaborative Center on Photoelectric Technology and Nano Functional MaterialsInstitute of Photonics&Photon-TechnologySchool of PhysicsNorthwest UniversityXi’an710069China

Heterostructures based on new advanced materials offer a cornerstone for future optoelectronic devices with improved photoelectric *** alignment is crucial for understanding the mechanism of charge carrier transportation and interface dynamics in ***,we grew SnS_(2)/Bi_(2)X_(3)(X=Se,Te)van der Waals heterostructures by combining physical vapor deposition with chemical vapor *** band alignment,measured by high-resolution X-ray photoelectron spectroscopy,suggested the successful design of type-Ⅰ SnS_(2)/Bi_(2)Te_(3) and type-Ⅱ SnS_(2)/Bi_(2)Te_(3) *** SnS_(2)/Bi_(2)X_(3) heterostructure greatly improved the photoelectric response of a photoelectrochemical-type *** photocurrent densities in the type-Ⅰ SnS_(2)/Bi_(2)Te_(3) and type-Ⅱ SnS_(2)/Bi_(2)Te_(3) heterostructure-based devices were more than one order of magnitude higher than those of SnS_(2),Bi_(2)Te_(3),and Bi_(2)Te_(3).The improved photoelectric properties of the SnS_(2)/Bi_(2)X_(3) heterostructures can be explained as follows:(i)the photoexcited electrons and holes are effectively separated in the heterostructures;(ii)the charge-transfer efficiency and carrier density at the interface between the SnS_(2)/Bi_(2)X_(3) heterostructures and the electrolyte are greatly improved;(iii)the formed heterostructures expand the light absorption *** photoelectric performance was further enhanced by efficient light trapping in the upright SnS_(2).The photoelectric response is higher in the type-Ⅰ SnS_(2)/Bi_(2)Te_(3) heterostructure than in the type-Ⅱ SnS_(2)/Bi_(2)Te_(3) heterostructure due to more efficient charge transportation at the type-Ⅰ SnS_(2)/Bi_(2)Te_(3) heterostructure/electrolyte *** results suggest that suitable type-Ⅰ and type-Ⅱ heterostructures can be developed for high-performance photodetectors and other optoelectronic devices.

关键词： SnS_(2)/Bi_(2)Se_(3) SnS_(2)/Bi_(2)Te_(3) type-Ⅰheterostructure type-Ⅱheterostructure photoelectric response photodetector

Thickness effect on solar-blind photoelectric properties of ultrathinβ-Ga_(2)O_(3)films prepared by atomic layer deposition

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Chinese Physics B 2023年第4期32卷 707-713页

作者：王少青程妮妮王海安贾一凡陆芹宁静郝跃刘祥泰陈海峰 The Key Laboratory of Advanced Semiconductor Devices and Materials Xi’an University of Posts&TelecommunicationsXi’an 710121China The State Key Discipline Laboratory of Wide Band Gap Semiconductor Technology Xidian UniversityXi’an710071China

Theβ-Ga_(2)O_(3)films with different thicknesses are prepared by an atomic layer deposition *** influence of film thickness on the crystal quality is obvious,indicating that the thicker films perform better crystal quality,which is verified from x-ray diffraction(XRD)and scanning electron microscope(SEM)*** Ga_(2)O_(3)-based solar blind photodetectors with different thicknesses are fabricated and *** experimental results show that the responsivity of the photodetectors increases exponentially with the increase of the film *** photodetectors with inter-fingered structure based on 900 growth cyclesβ-Ga_(2)O_(3)active layers(corresponding film thickness of 58 nm)exhibit the best performances including a low dark current of 134 fA,photo-to-dark current ratio of 1.5×10^(7),photoresponsivity of 1.56 A/W,detectivity of 2.77×10^(14)Jones,and external quantum efficiency of 764.49%at a bias voltage of 10 V under 254-nm DUV *** photoresponse rejection ratio(R_(254)/R_(365))is up to 1.86×10^(5).In addition,we find that the photoelectric characteristics also depend on the finger spacing of the MSM *** the finger spacing decreases from 50μm to10μW,the photoresponsivity,detectivity,and external quantum efficiency increase significantly.

关键词： β-Ga_(2)O_(3) film thickness solar blind photodetectors photoelectric response

Atomically Precise Doping in Chalcogenide-based Coreless Nanocluster for Tunable Electro-/photoelectric and Photoluminescent Properties

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Atomically Precise Doping in Chalcogenide-based Coreless Nan...