| Silver nanomaterials,combined with the unique structure and excellent performance of metallic silver and nanomaterials,possess unique electrical,optical,thermal,catalytic characteristics and so on,and have wide application prospects in film electrodes,catalysts,sensors,antibacterial sterilization and many other fields.Silver nanomaterials such as silver nanowires,silver nanoparticles and transparent conductive films have been become the key electrode materials for display,solar cell and heating devices.At present,there are some problems in the preparation of silver nanomaterials,such as low yield,high impurity content and poor process stability,which seriously restrict the application of silver nanomaterials in electrode and related fields.Optimizing preparation process of silver nanomaterials,developing new preparation technology of conductive films and controlling the photoelectric properties have become the research hotspots in film electrodes of photoelectric devices.Based on systematic review of the research progress and application status of silver nanomaterials and their conductive films,this research focuses on the preparation of silver nanomaterials and conductive films.The silver nanowires and silver nanoparticles were synthesized by polyol method,and the particle-free silver ink was prepared.With three silver nanomaterials as raw materials,the transparent conductive films,dense conductive films and patterned conductive films were achieved respectively.The influence of the synthesis process parameters on the morphology and size of silver nanomaterials were investigated,and the effect of coating process and treatment on the photoelectric properties and surface roughness of the conductive films were revealed.The resultant transparent conductive films,dense conductive films and patterned conductive films built an important foundation for their application in the film electrodes of photoelectric devices.Detailed research contents and results are as follows:（1）Controllable synthesis of silver nanowires and preparation of transparent conductive films.With AgNO3 as silver source,EG or other polyols such as diethylene glycol,triethylene glycol or glycerol as solvent and reducing agent,PVP as heterotropic growth control agent,and FeCl3 or mixed with NaBr as main ion assistant,the silver nanowire dispersion was prepared by polyol method.The silver nanowires with the ratio of length to diameter up to 1029,the ultra long（>120μm）silver nanowires and ultra-fine（<20 nm）silver nanowires can be obtained,respectively.With the help of low-speed centrifugation and acetone precipitation process,the silver nanowire dispersion with the mass ratio of more than 97%and solid content of 10 mg·mL-1 was obtained,and the mass production of 10-100 times was achieved.A transparent conductive film with a transmittance of 81.6%and a resistance of 11.36Ω·sq-1 was prepared by spin coating and sintering.（2）Synthesis of silver nanoparticles and preparation of dense conductive films.Silver nanoparticles were prepared in different systems including water system,toluene system,fluorine-containing solvent system,glycol system and so on,and the morphology characteristics of their products were studied.Under glycol system,silver nanoparticles with an average particle size of 43 nm and uniform particle size distribution can be obtained.With ethanol dispersion of silver nanoparticles as raw material,the dense conductive films were successfully by dip coating method combined with rapid sintering.The dense conductive films with better surface morphology（thickness 1.97μm,roughness about 2 nm）can be achieved by dipping40 times at the lifting speed of 500μm·s-1.After further microwave sintering at 500 W power for 50 s,the sheet resistance of dense conductive films is only 0.75Ωsq-1,and the surface roughness is1 nm.（3）Preparation of patterned conductive films by combining laser direct writing and transfer method.Using silver nitrate as silver source,ethanol and a small amount of deionized water as solvent,FSO-100 as main surfactant,PVP as viscosity regulator and surfactant,a particle-free silver nano ink was prepared,and the corresponding patterned conductive films were prepared by laser direct writing technology and transfer method.When the laser power is 3 W and the scanning speed is 2.6 cm·s-1,the patterned conductive film with a sheet resistance of 0.9Ω·sq-1 can be prepared.The work function of the patterned conductive film can be tuned from 4.25to 2.98 and 4.44 eV by introducing ZnO and Au into the films,respectively.Through the,a patterned conductive film with smooth surface（surface roughness of 4.2 nm）can be obtained by combining laser direct writing with resin transfer method. |
