Measurement and Model Evaluation of Solubility of 2-(4-tert-Butylphenyl)-5-(4-biphenyl)-1,3,4-oxadiazole in Different Organic Solvents at Various Temperatures

2-(4-tert-Butylphenyl)-5-(4-biphenyl)-1,3,4-oxadiazole (PBD) is one of the most widely used electron transport layer materials in optoelectronic devices, and studies on the solubility of PBD in various solvents are critical for development of solution-processable roll-to-roll electronic devices. In this study, the isothermal saturation method is used to determine the solubility data of PBD in 12 commonly used organic solvents. The experimental solubility of PBD increases gradually with enhanced temperature for the examined temperature range of 283.15–323.15 K in n-hexane, methanol, ethanol, isopropanol, tetrahydrofuran (THF), acetonitrile, ethyl acetate, N-methylpyrrolidone (NMP), toluene, and chlorobenzene, while the temperature ranges were 293.15–333.15 K and 273.15–303.15 K for dimethyl sulfoxide and dichloromethane, respectively. The obtained solubility values of PBD are correlated by three models including the modified Apelblat equation, λh equation, and Yaws equation. Comparison of the calculated Akaike information criterion values resulted in selecting the optimal model for each solvent. Of the five solvents calculated, n-hexane, methanol, toluene, THF, and NMP, the λh equation provides an optimal fit. Both the modified Apelblat equation and the Yaws equation work well in chlorobenzene. Among the other six solvents, the fit of the Yaws equation is the best. These results of solubility provide the basic data for the synthesis of PBD nanoparticles via high-gravity-assisted antisolvent precipitation processing.