Preparation Of Polydopamine Nanomaterials And Their Applications In Polymer Solar Cells And Photocatalytic

Dopamine(DA)can adsorb onto most solid materials and self-polymerize into polydopamine(PDA).PDA has abundant functional groups and can react with amino,sulfhydryl,metal ions and so on.In metal oxide@PDA nanocomposites,PDA plays multiple roles under the action of light and the most important is increasing light absorption and accelerating electron transfer,thus reducing photogenerated electron and hole recombination.The thickness of PDA coating has an important influence on the above function.This paper focuses on the preparation of dopamine-coated TiO2 and ZnO nanocomposites and their applications in photocatalysis and polymer solar cells.The main contents are divided into the following four parts:1.Photocatalytic activity of TiO2@PDA.By changing the concentration and polymerization time of DA,TiO2@PDA was prepared and used for photocatalytic degradation of dyes.It showed that the degradation rate of Rhodamine B(RhB)was the highest by TiO2@PDA obtained at a DA concentration of 0.4 mg/mL and a polymerization time of 2 h.Compared with the uncoated TiO2,after 1.5 h of UV-Vis irradiation,the degradation rate of RhB by TiO2@PDA was increased from 94.42%to 99.28%,which increased by 4.86%.After 1.5 h of Vis irradiation,the degradation rate increased from 42.36%to 77.40%,which increased by 35.04%.It showed that surface modification of TiO2 with suitable thickness of PDA effectively increased light absorption and promoted separation of photogenerated carriers.HPLC-MS revealed the differences in photocatalytic degradation mechanism of TiO2@PDA to RhB under UV-Vis and Vis irradiation.Under Uv-Vis irradiation,OH can directly attack RhB to break the benzene ring into N,N-diethyl acetamide,and then degrade to NH4+,NO3-,CO2 and H2O;Under Vis irradiation,·OH attacked the remaining parts of RhB after the removal of the amino group,cracked them into macromolecular acids,which were further degraded into CO2 and H2O.2.Photocatalytic activity of ZnO@PDA.By changing the concentration and polymerization time of DA,ZnO@PDA was prepared and used for photocatalytic performance.When the DA concentration was 0.15 mg/mL and the polymerization time was 2.5 h,ZnO@PDA had the best degradation effect on RhB.Compared with the uncoated ZnO,fter 1 h of UV-Vis irradiation,the degradation rate of RhB by ZnO@PDA increased from 94.7%to 99.7%,which increased by 5%.After 1 h of Vis irradiation,the degradation rate increased from 25.6%to 29.4%,which increased by 3.8%.PDA in ZnO@PDA has little effect on improving the utilization of light energy,but it can improve photocatalytic performance by accelerating electron transfer.3.TiO2@PDA used as the electronic transfer layer(ETL)of the inverted PTB7:PC71BM solar cell.The surface modification of TiO2 by PDA was realized by DA atomization on the surface of TiO2.Without changing the thickness of the active layer,the introduction of PDA for the interface design and construction of the ETL can improve the charge injection rate and make the electrons easy to enrich and transport.When the atomization time of DA wass 20 min,the device performance was improved greatly:short circuit current density(Jsc)reached 10.48 mA/cm2,open circuit voltage(Voc)increased to 0.67 V,filling factor(FF)increased to 0.58,and photoelectric conversion efficiency(PEC)reached 4.02%.4.ZnO@PDA used as the ETL of the inverted PTB7:PC71BM solar cell.It was found that different atomization time,i.e.different PDA thickness,had a great influence on the performance of the device.When the atomization time of DA was 10 min,the device performance was best.Jsc reached 10.54 mA/cm2,Voc increased to 0.63 V,the FF increase dto 0.59,and PEC reached 3.87%.