Study On The Optoelectronic Functions Of Perylene Bisimide Based Organic-Inorganic Hybrid Materials

Traditional organic materials are structural diverse,freely soluble,easy-processable,and their energy level can be easily tuned by introduction of substituent groups.However,most of them suffer from high exciton binding energy,low carrier mobility,structure instability and poor solvent resistance.Inorganic materials possess,in the contract,low exciton binding energy,hight carrier mobility,stability,mechanical strength and solvent resistance,while there are weak at structure diversity,processability,fixed energy level.Thus,the combination of organic and inorganic material is a promising pathway toward high-performance photoelectronic materials by developing their advantage and to overcoming their weakness simultaneously.Based on a classical organic semiconductor,perylene bisimide,we investigated its interaction with metal oxide/sulfide and their photoelectronic property.The detailed information is listed as follows:1. The electron transfer process between PBI-H and point defects in ZnO and its effect to carrier transportation are investigated based on previous work of our group about ZnO:PBI-H photoconductive material.In the presence of PBI-H,the defect-induced fluorescence of ZnO was reduced by 50%indicating the decrease of defect density.Electron paramagnetic spectrum revealed that PBI-H passivated a portion of oxygen vacancies and zinc vacancies by donating its HOMO electron in dark.Threshold voltage of ZnO:PBI-H TFTs was significantly decreased.By introducing a mathematical model,the defect distribution inside ZnO was successfully extracted.The total amount of point defect in ZnO was found to be reduced and their distribution was closer to conduction band.Transient photovoltage test found that carrier lifetime at ZnO:PBI-H/polymer interface,which is similar to that in organic photovoltage?OPV?devices,increased to 28.3?s,which was much higher than that of ZnO/polymer interface?2.5?s?,indicating that the introduction of PBI-H slowed down the carrier recombination at ZnO interface.2. The formation of cp-PBI mono/dianion under low energy photon?visible light and near-infrared light?excitation was investigated,and it was adapted for hydrogen evolution.It was found that cp-PBI could be charged to mono-or dianion under visible-light excitation in the presence of triethanolamine.?TEOA?Further research revealed that deactivation of cp-PBI excited state and electron transfer between it and TEOA were competing reactions.The attraction between TEOA and four carboxyl groups on cp-PBI played an important role in promoting the electron transfer process.Time-resolved absorption spectra found that the life-time of cp-PBI mono-/dianion as long as several tens of minutes.The above two conditions enable the formation of cp-PBI mono-/dianion via consecutive charging.cp-PBI was loaded onto Ti O₂ nanoparticles for hydrogen evolution test.This work presents a different strategy of consecutive charging mechanism providing new pathway toward full spectrum driven hydrogen evolution.3. In this part,Ag₂S/PDIN complex was synthesized for wastewater treatment.Due to large amount of hydroxy group,PDIN nanorod was able to disperse in water.Under visible-light excitation,pure PDIN nanoraod could decompose methyl orange?MO?into H₂O and CO₂ with low efficiency.Ag₂S itself is a promising photocatalyst,but its dispersibility in water is poor.When Ag₂S was loaded onto PDIN nanorod,it was found that Ag₂S/PDIN complex decomposed MO more efficiently than either Ag₂S or PDIN nanorod.Further research reveal that such improvement was ascribed to the following three fact:1.Dispersibility of Ag₂S was improved after it was loaded onto PDIN nanorod;2.Absorption complementation of Ag₂S and PDIN nanorod enabled the fully utilized of visible and near-infrared photons;3.The energy level different promoted exciton fission at Ag₂S/PDIN interface.