Block Copolymers Regulated Efficient Heterojunction Thin Film Materials

Block copolymers?BCPs?,with its weak impact on response characteristics and under given conditions can self-assemble into a variety of topography have attracted people.Especially in the BCPs film,the ordered cylinder phase structure oriented perpendicularly of the substrate obtained by modulating in the application of nanomaterials causes the interest of researchers.In this thesis,?1?we have systematically investigated the phase behavior of polystyrene–poly?methyl methacrylate??PS–b–PMMA?diblock copolymer.First,we use PG?PS-r-PMMA containing a small amount of glycidyl methacrylate random copolymer?modifying the substrate?silicon and ITO conductive glass?;And then thermal annealing and acetone annealing are used to modulating PS–b–PMMA diblock copolymer and obtain PS cylinder phase films oriented perpendicularly of the substrate?silicon and ITO conductive glass?;Finally,we obtain the PS cylinder films only by removing the PMMA phase using UV and glacial acetic acid etching.This cylinder films are used as a template to prepare CdS film with PS cylinder films using chemical bath deposition and electrochemical deposition;Finally,the PS cylinder filme are removed by sintering at high temperature and CdS nanoporous films were obtained.?2?TiO₂ nanoparticles are synthesized by solvent evaporation approach by usinghydrophilicpolyoxyethylene-polyoxypropylene-polyoxyethylene(PEO₁₀₆PPO₇₀PEO₁₀₆,F127)triblock copolymer as template agent,tetrabutyl titanate?TBOT?as titanium source;Finally,we obtain the preparation of mesoporous TiO₂ nanospheres through a two-step calcination?N₂ atmosphere and air atmosphere?removing the BCPs template.First,The regulation of PS cylinder phase films oriented perpendicularly of the substrate?silicon and ITO conductive glass?are investigated by SEM.The results show that we successfully obtain PS cylinder phase films oriented perpendicularly of the silicon and ITO conductive glass by PG modification of the substrate?silicon and ITO conductive glass?,the thermal annealing,acetone vapor annealing and UV etching methods.Then the results of the preparation of ordered cadmium sulfide?CdS?nanoporous films show that we successfully obtain ordered cadmium sulfide?CdS?nanoporous films with the characteristic diffraction peaks of CdS in XRD,the line of S and Cd elements in XPS and the main elements of the film being S and Cd in EDS.The results of SEM show that the particle size of CdS thin films prepared by chemical deposition is uneven and the film is in crack and the CdS thin films prepared by electrochemical deposition ia uniform and compact.So,electroche mical deposition method is the best solution to prepare CdS thin films.And the optimal conditions:the concentration ratio of chromium chloride and sodium thiosulfate being 10:1,pH=2,cathodic electrodeposition,deposition temperature of 40 ^oC water bath,deposition potential of-1 V,deposition time of 2 h.Then prepared ITO/CdS/P3HT/Au bulk heterojunction solar cell,and get open circuit voltage being 0.64 V,a lower?0.6?fill factor,but has not been,short-circuit current and effectively cell conversion efficiency.The results show that we successfully obtain mesoporous TiO₂ nanospheres with the characteristic diffraction peaks of TiO₂ in XRD and being anatase,the preparation of TiO₂being mesoporous material and the pore size between 10 and 40 nm.The BET results show that when the amount of template F127 is 1.0 g and the amount of TBOT,formic acid,hydrochloric acid are 1.0 g,1.97 mL,2.03 mL,an average pore size of the synthesized mesoporous TiO₂ nanospheres is 10.42 nm and its specific surface area is 117.44 m²/g.And also studied its photocatalytic properties,but the catalytic efficiency is not ideal,only about50%.And prepared DSSC of mesoporous TiO₂ being used as the light anode and the area of the battery is approximately 0.25 cm².The results are open circuit voltage being 0.66 V,short-circuit current being 3.05 mA/cm²,the fill factor being 0.52 and effectively cell conversion efficiency being only 1.04%.