Preparation And Photoelectric Properties Of 2D Melanophosene In Liquid Phase

Black Phosphorus（BP）semiconductor material is a direct band gap two-dimensional semiconductor material with a high carrier migration rate(～1000 cm²·V^-1·s^-1)and a tunable direct band gap（0.3-2.0 e V）,which can make up for the shortcomings of graphene and transition metal sulfides,showing a wide range of applications and prospects in the manufacturing of electronic and optical semiconductor components.It is very difficult to prepare BP crystals by vapor deposition method,and much problems such as extremely high risk and high cost.Mechanical peeling method can obtain high-quality BP crystals with few layers,but the yield of this method is very low and the number of layers is uncontrollable.Ultrasonic peeling can be mass-produced,the size of the few layers of BP obtained is smaller,almost all of the nanometer level.Therefore,researchers have been searching for a method to prepare FL-BP with high yield,large size and high quality.In the conjugated structure of BP,the remaining lone pairs of electrons in the hybrid P atom cause the BP crystal to be easily oxidized under the air condition,which greatly reduces the performance of the BP device.Therefore,how to develop a universal preparation method for high-stability,high-quality,low-layer BP crystals is another problem faced by researchers.In response to these problems,we first developed a hydrogen-free electrochemical layering strategy using weak Lewis acid intercalation to achieve exfoliation,which can prepare high-quality super large FL-BP single crystal domains.On the basis of peeling,a method of simultaneous preparation and passivation was further proposed,and a FL-BP nanosheets with high stability and high quality were obtained.The specific research content of this paper is as follows:（1）Preparation and characterization of ultra large size and FL-BP.In an organic solvent,the bulk BP was stripped,and the effects of experimental conditions such as the acidity of the coordination anion,intercalation time,working voltage,and H⁺and H₂O concentrations on the production rate and size of the FL-BP were systematically studied.After peeling by electrochemical peeling method,high-quality BP nanosheets with few layers,uniform surface,about 50μm in size（maximum size up to 100+μm）can be obtained.（2）Application of super large size and few layers of BP.Constructed BP nanosheet field effect transistor（FET）devices and flexible electronic（TFT）devices.Using the optoelectronic test platform,the FET was tested for electrical and optical performance at room temperature and low voltage,and then the mobility and subthreshold swing of the device were analyzed.Electrical properties such as amplitude and threshold voltage and optical properties such as response time and responsivity.（3）Passivation of BP nanosheets.It is explored that on the basis of electrochemical preparation of large-size BP nanosheets,metal cations are added to the electrolyte,and the metal cations are electrochemically reduced to metal nanoparticles at the cathode,which combine with the lone pair of P electrons to prevent BP from being oxidized.