Preparation Of Highly Stable Nano Metal-free Phthalocyanine And Its Photoconductive Properties

Metal-free phthalocyanine(H₂Pc)is one of the important organic optoelectronic materials,has good near infrared photoelectric response performance,and is a very active frontier research direction in the field of organic optoelectronic devices.H₂Pc was synthesized by condensation of 1,3-diiminoisoindoline under basic conditions.The acid-paste method was used to purify the amorphous product,and the heat-induced phase transition was studied in a tube furnace with adjustable atmosphere.The effects of H₂Pc crystal form transformation were studied by means of speed-up,speed-down and gradient heating and different holding time.When T=235?and holding for 2 h,the H₂Pc prepared by heating at 3-5?/min and 5-3?/min are both?and?mixed crystal forms,which respectively are 71.77%of?-H₂Pc and 84.25%of?-H₂Pc.It shows that the heating methods of increasing speed and decreasing speed are conducive to the formation of?-H₂Pc and?-H₂Pc respectively;when T=280?,the crystallinity of?-H₂Pc increases obviously,and when the time gradient is 2 h,the crystallinity of?-H₂Pc Up to 100%.Sulfuric acid solution of the H₂Pc was directly added dropwise to the binary dispersion medium to prepare?and?-H₂Pc nanoparticles.The binary dispersion medium composed of methyl ethyl ketone/water was used to study the effects of the dispersion medium composition,stirring speed,crystal form adjustment temperature and time on the degree of H₂Pc conversion.At a volume ratio of 1:3 butanone/water,under the conditions of 600 rpm,40?and crystal form adjustment for 5 h,a highly crystalline stable and highly dispersed stable?with a particle size of 68.8 nm and a crystallinity greater than 90%was obtained?-H₂Pc.Using it as a carrier generation material to prepare a laser organic photoconductor(OPC),the photoconductive response performance is:V₀=698.24 V,V_r=29.30 V,R_d=12.24 V/s,E_1/2=0.60?J/cm².Using 1,2-dichloroethane/water and o-dichlorobenzene/water as binary dispersion media,the effect of H₂Pc crystal form conversion was studied.When the former is used as a dispersing medium,when the crystal form adjustment temperature is T=-5?or T>30?,the product is?-H₂Pc with a crystallinity greater than 97.3%.T=0?-20?,the product is mainly in the crystal form of?-H₂Pc.Using the latter as the dispersion medium,the highly crystallized?-H₂Pc products are obtained under various conditions.The study of dispersion stability found that the dispersion stability of?-H₂Pc prepared by o-dichlorobenzene/water as the dispersion medium(2.1%)was slightly higher than that of 1,2-dichloroethane/water(3.8%).Using the prepared?-H₂Pc as a carrier generation material to prepare OPC,the former device:V₀=734.9 V,R_d=13.8 V/s,V_r=50.7 V,E_1/2=0.5?J·cm^-2;the latter device:V₀=671.0 V,R_d=40.0 V/s,V_r=80.0 V,E_1/2=0.8?J·cm^-2.