Escalab 250xi

The electrical characterizations of the OFETs were carried out on a standard probe station with a Keysight B1500A semiconductor device analyzer in ambient air. Field-effect hole mobility in saturation regime (μ_sat) and threshold voltage (V_th) were extracted via the relation I_D = −(W/2L)μ_FEC_i(V_G − V_th)², where W, L, and C_i are the channel width, channel length, and areal capacitance of the gate dielectric, respectively. The effective carrier mobility (μ_eff) was calculated by μ_eff = r × μ_sat, where r is the reliability factor defined as [38 (link)] $r={\left[\left(\sqrt{\left|I_{\text{on}}\right|}-\sqrt{\left|I_{\text{off}}\right|}\right)/{\left|V_{\text{G}}\right|}^{\max }\right]}^2/\left(\left({WC}_{\text{i}}/2L\right){\mu }_{\text{sat}}\right)$ . The dielectric spectra were measured by a Keysight E4980A LCR meter on the MIS capacitors with series resistance corrected. The luminance of the OLEDs was measured by a TOPCON BM-7AS luminance colorimeter. To characterize the material properties of the PVA layer, we used XPS (Thermo Scientific, Escalab 250Xi), XRF (Rigaku, ZSX Primus II), and Fourier-transform infrared spectroscopy (FTIR) (PerkinElmer, Frontier), and the layer thickness was measured by a stylus profiler (KLA Tencor, D-600).

Optical images were captured by a confocal microscope (Keyence, VK-X1000). Characterizations such as SEM (Phenom, Eindhoven, Netherlands) and AFM (Bruker, Billerica, MA, USA) were performed to examine the detailed morphologies. The chemical compositions of the rGO film were analysed by XPS (Thermo Escalab 250Xi) and XRD (Rigaku SmartLab). The spatial element distribution was analysed using EDS (Phenom, Prox). The Raman spectra were measured by a spectrometer (LabRAM HR Evolution) with an excitation wavelength of 532 nm. The light absorption of the GO film and rGO-LIPSS was investigated by a UV–Vis–NIR spectrometer (Agilent, Cary 5000) over a wavelength range of 200–2000 nm. The rGO samples were illuminated by an LED light source (OPTO SIGMA, SLA-100), and the photoresponse was measured using a 4200A-SCS Parameter Analyzer (Keithley, USA). The same LED light with a power of 65 mW and an infrared camera (Image@IR 8300) were used to characterize the photothermal properties and record the temperature.