Combined experimental and theoretical study of the novel ferrocene derivatives and examining the effect of E-Z stereoisomerism on their optical properties

Deposition and Characterization of Heterostructures Based on Doped Ferrocene for Film-Device Applications

“…The results shown in Figure 4a are, as expected, given the heterostructure's opacity, with the lowest transmittance produced by FcPF 6 :DHAQ/nylon(ZnPc). According to Aslan et al [40], the transmittance of the investigated heterostructures was detected to be relatively weak and in line with the observation. Interestingly, in the region between 600 and 700 nm the transmittance of both heterostructures, decreases significantly, a behavior related to the charge transfer transition between the Fe(II) and cyclopentene in de Fc [41][42][43][44].…”

“…On the other hand, the E t values are higher than the E g , and their difference corresponds to the binding energy of the exciton [40,54]. According to previous studies [40,55,56], the binding energy (EB) values for FcPF 6 :DHAQ/nylon(ZnPc) and FcPF 6 :DAAQ/nylon(ZnPc) are in the range between 0.5 and 1.5 eV (see Table 3). The optical characteristics of the studied heterostructures favor their application in optoelectronic and photovoltaic devices.…”

“…The heterostructure with DHAQ displays lower E g and E t values, which could indicate a greater charge transport with respect to FcPF 6 :DAAQ/nylon(ZnPc). It is important to consider lower E g and E t values for both heterostructures with respect to those previously reported for Fc-base, doped semiconductors [27,40,52]. The main causes of the phenomenon could be: (i) the intermolecular interactions between Fc and its dopant, (ii) the alternate between the electron-donor Fc and the electron-acceptor DHAQ/DAAQ, which generates rich zones and electron-deficient zones favoring the charge transport, and (iii) the presence of the ZnPc and its π-π* transitions, both HOMO-LUMO between their symmetry orbitals a u and b g (Q band), and from their occupied symmetry orbitals b u and a u of lower energy, to the LUMO (B band).…”

“…As mentioned before, valuable optical heterostructures depend keenly on the optical band gap (E g ) and transport energy band gap (E t ) [40,[47][48][49][50][51]. At the absorption edge α > 10 4 cm −1 (see Figure 4b), the energy dependence of the band gap absorption coefficient is given by Equation ( 1) [47,48] using the Tauc plot method [39]:…”

“…This last one could be the most important, because the ZnPc contained in nylon(ZnPc) favors the optical behavior and places these heterostructures within an organic low-bandgap semiconductor range [53]. On the other hand, the E t values are higher than the E g , and their difference corresponds to the binding energy of the exciton [40,54]. According to previous studies [40,55,56], the binding energy (EB) values for FcPF 6 :DHAQ/nylon(ZnPc) and FcPF 6 :DAAQ/nylon(ZnPc) are in the range between 0.5 and 1.5 eV (see Table 3).…”