“…where ε is the relative dielectric constant; Vbi is the built-in potential; Vr is the applied voltage; ND is assumed to be the concentration of charge carriers. Generally, the ND value in Equation (1) is the density of uncompensated donors or acceptors [31], but in our case, charge carrier transport in PbS-TBAI is dominated by electron transport since PbS-TBAI shows n-type behavior [32][33][34]; therefore, we assume ND as the concentration of free charge carriers (electrons). From the minimum capacitance in Figure 3, which is observed at a negative bias, the dielectric constant can be determined from the equation for the capacitance of a flat capacitor, C dep = εε 0 S W dep [29], where C dep is the measured capacitance, ε is the relative dielectric constant, S is the pixel area, W dep is the depletion region width of the device that equals the geometric thickness when the device is fully depleted, and ε 0 is the vacuum permittivity.…”