High Photosensitive Y-type Titanylphthalocyanine Nanoparticles: Preparation And Photoelectric Properties

Y-type titanylphthalocyanine(Y-TiOPc)is a kind of very important organic photosensitive materials.This paper mainly includes the preparation and organic photoelectric application of high photosensitive Y-TiOPc nanoparticles,and the theoretical study on the relationship between crystal structures and photoelectric properties in different polymorphs of TiOPc by quantum chemistry calculations.A microemulsion phase transfer method was developed to prepare Y-TiOPc nanoparticles.The effects of feed temperatures,holding temperatures,transition time and stirring rate on the crystal form and particle size of the prepared TiOPc nanoparticles have been investigated.The prepared Y-TiOPc nanoparticles with 2.3 ± 0.8 nm showed an excellent dispersibility(zeta potential:-50.0 mV)in the solution of polyvinyl butyral,methylethylketone and cyclohexanone,supported by the only 3.12% of transmission rate variation during 60 days.The excellent solvent-stabilized dispersibility mainly relied on the multiple factors interaction of Brown movement,electrostatic repulsion force,steric hindrance and solvent repulsive force.A new method of the recyclable acid solvent process has been developed to prepare Y-TiOPc nanoparticles.TiOPc crude dissolved in benzenesulfonic acid/dichloromethane solution was firstly precipitated in cold water,then the wet cake of TiOPc precipitation was transformed into Y-TiOPc nanoparticles.The optimal conditions for the preparation of Y-TiOPc nanoparticles were that: acid soluble temperature:-10 ?,precipitation temperature: 0 ?,transformation solvent: dichlorobenzene,transformation temperature: 50? and the transformation time: 1 h.Atmospheric distillation method was used to study the acid-solvent recovery of dichloromethane.The recovery of DCM was 78.46% and the purity was 99.88%.Through conditional experiments to determine the optimal preparation process of multilayer organic photoconductors(OPCs): drying temperature and time of the charge generation layer were respectively 60? and 15 min,the drying temperature and time of the charge transport layer were respectively 80? and 60 min.Under the optimal process,the photosensitivity of the organic photoconductor prepared by Y-TiOPc nanoparticles with 2.3 ± 0.8 nm obtained from microemulsion phase transfer method as charge generation material was 0.064 ?J/cm2 after correction,which was the best value reported in the literatures.The near-infrared organic photodetectors(NIR OPDs)based on ITO/glass(rigid substrate)and ITO/PET(flexible substrate)were prepared with the cnfiguration of ITO/Y-TiOPc@PVB/m-TPD@PC/Al.The type of the prepared NIR OPDs were electron trap-assisted photomultiple photodetectors.The NIR OPDs with the rigid substrate showed an excellent photosensitivity properties with the highest external quantum efficiency(EQE)of 354,200%,the maximum photoresponsivity(R)of 2,227 A/W,and the highest normalized detectivity(D*)of 3.1 × 1014 Jones under 780 nm with a low intensity of 0.1 ?W/cm2 at +15 V/?m.The NIR OPDs with the flexible substrate showed good flexibility under the bending diameter of 3 cm,2 cm and 1 cm.Using the quantum chemical theory to study the relationship between the TiOPc crystal structures and the photoelectric properties.The hole/electron reorganization energy and hole/electron transfer integrals of ?-??-and Y-TiOPc were calculated.According to the results of the hole/electron transfer integrals of the adjacent molecules in the crystal cell,the optimal charge transport channel in the crystal of ?-??-and Y-TiOPc were determined,respectively.