Uv 3600 spectrophotometer

¹H and ¹³C NMR spectra were recorded on a Bruker Varian and Ascend 400 MHz spectrometer in CDCl₃. UV–Vis absorption spectra were recorded on a Shimadzu UV-3600 spectrophotometer, and photoluminescence spectra were measured on a Hitachi F-7000 spectrophotometer. Cyclic voltammetry (CV) measurements were carried out with a CHI 600D system in acetonitrile solution containing 0.1 M tetrabutylammonium tetrafluoroborate (TBABF₄) as the supporting electrolyte, Ag/AgNO₃ as the reference electrode, a platinum wire as the counter electrode, and a platinum working electrode. The current density–voltage–luminance (I–V–L) characteristics were measured, and the electroluminescence (EL) spectra of the phosphorescent OLEDs were recorded using a Keithley 2400 source measurement unit and a CS-1000 spectrophotometer. A Keithley 2400 source measurement unit and a CS-1000 spectroradiometer were used to evaluate the device performance. The molecular weight was measured by gel permeation chromatography (GPC) with polystyrene standard and THF as the eluent using an Agilent 1260 Series instrument. The surface morphologies were measured by atomic force microscopy (AFM; Park Systems NX-20) in the non-contact scanning mode.