Experimental verification of nanonization enhanced solubility for poorly soluble optoelectronic molecules

Solubility enhancement has been a priority to overcome poor solubility with optoelectronic molecules for solution-processable devices. This study aims to obtain experimental data on the effect of particle sizes on the solubility properties of several typical optoelectronic molecules in organic solvents, including the solubility results of 1,3-bis(9-carbazolyl)benzene (mCP), 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene (TPBi) and 2-(4- tert -butylphenyl)-5-(4-biphenyl)-1,3,4-oxadiazole (PBD) in ethanol and acetonitrile , respectively. Nanoparticles of mCP, TPBi and PBD with sizes from dozens to several hundred nanometers were prepared by solvent antisolvent precipitation method and their solubility were determined by using isothermal saturation method. The saturation solubility of nanoparticles of three kinds of optoelectronic molecules exhibited increase of 12.9%−25.7% in comparison to the same raw materials in the form of microparticles. The experimental evidence indicates that nanonization technology is a feasible way to make optoelectronic molecules dissolve in liquids with enhanced solubility.