Preparation Of CdS/MoS₂ Nano Heterojunction And Study On Carrier Dynamics

Nanomaterials show many interesting optoelectronic properties and great application potential in the field of light capture and light emitting devices.With the development of nanomaterials,people have opened a special window to understand the world.In order to solve the problem of global energy shortage and environmental pollution,in recent years,semiconductor photocatalytic technology for converting solar energy into chemical fuel has been widely studied.Regarding semiconductor-based photocatalysts,Cd S has received widespread attention because of its relatively narrow band gap in response to visible light and the negative potential at the edge of the conduction band is sufficient to reduce protons.Research shows that Cd S-based photocatalysts have excellent photocatalytic performance in solar power generation and environmental purification.However,for the fluorescent material Cd S,the rapid recombination of light-excited carriers affects the further improvement of its efficiency in the field of optoelectronics and catalysis.On the one hand,cadmium sulfide has good absorption performance for visible light with a wavelength less than 516 nm.On the other hand,it has good carrier transport ability,which can make photo-generated electrons and holes move in a timely and efficient manner,prolong the life of photo-generated carriers,and has high photocatalytic activity.The introduction of transition metal disulfide shows excellent catalytic hydrogen evolution reaction.At the same time,the transition metal disulfide can generate more photo-excited carriers and have a certain grooming effect on the photo-excited carriers,which greatly improves photoelectricity.Device performance.In this paper,Cd S nanocrystals and Cd S/Mo S2 nanoheterojunctions are prepared by hot injection method.The effects of nanoheterojunctions on carrier diffusion and transport are explained by comparing the properties of two nanomaterials.First of all,in the introduction,some properties of nanomaterials and the way of characterizing nanomaterials are introduced.Nanomaterials with different structures,different components,and different physical properties use different ways of characterization.The preparation methods of Cd S nanocrystals are introduced,and some significant properties of Mo S2 nanostructures are described.Secondly,the specific preparation methods of Cd S nanocrystals and Cd S/Mo S2 nanoheterojunctions used in this experiment are described in detail.The hot injection method is used in this article.In 1993,Bawendi and his colleagues reported a general method for synthesizing chalcogen cadmium nanocrystals,which was later referred to as the "hot injection" method,so that the preparation had medium size uniformity.Cd Se nanocrystals(relative standard deviation of the size distribution ?r ~ 10%)become possible,where the average size can be controlled between 2 and 12 nm.Later,this hot injection method was extended to the synthesis of nanocrystals of other materials.The crystals formed by the crystals were relatively uniform in shape and uniform in size,which was a key factor in the research of nanomaterials.The materials were fully characterized by transmission electron microscopy,scanning electron microscopy,X-ray diffraction spectroscopy,and steady-state absorption spectroscopy.Then,using the femtosecond transient absorption technology and the I-V curve of light-excitation downloaded carrier transport,the carrier diffusion and transport characteristics of the nanoheterojunction were studied.The research shows that the introduction of Mo S2 will indeed produce more photo-generated carriers,which can greatly promote the transport of carriers in a directional electric field.