Figure (3a) illustrates the capacitance-voltage (C-V) characteristics of the PM6:Y7 blend, manifesting a hysteresis curve at 38 GHz. These measurements utilized a 1000 µm coplanar waveguide (CPW) with a 500 nm thick PM6:Y7 blend, conducted at room temperature. Capacitance values were derived by employing the two-port transmission line theory applied to S-parameters, with the propagation constant (γ) and line impedance (Z c ) determined from Equations S10 and S11 [refer to the ad-ditional section (C)]. A nonlinear response to the applied voltage was observed in capacitance, transitioning from 161.5 pF/m to 153.6 pF/m as the voltage increased from 0 to 40 V at 38 GHz. The distinctive butterfly-shaped curve in the C-V graph suggests dielectric nonlinearity of the PM6:Y7 blend.