ZnO nanoparticles were synthesized in the presence of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) ((PEO)128-(PPO)54-(PEO)128) triblock copolymer, through a precipitation and sol-gel method using Zn(CH3COO)2.2H2O as the zinc source with NaOH or Na2CO3 as a precipitating agent, respectively. The change of particle shape was dependent on the use of NaOH or Na2CO3. The crystallite size diminished when the concentration of (PEO)128-(PPO)54-(PEO)128 was increased. The energy gap varied in the range of 3.216-3.225 eV and 3.202-3.222 eV when NaOH and Na2CO3 were used, respectively. The dependence of the energy gap on the defect concentration and strain was explained.
Keywords: ZnO nanoparticles, Surface active polymer, Defect concentration, Strain, Optical properties.