## 3 Results and Discussion
Coplanarity of the molecule is expected to have frontier orbitals delocalized through the polymer's backbone, which might be beneficial to increase charge carrier mobility. Thermal properties of the **P(FDPP-TP)** polymer were investigated with TGA and DSC. The respective TGA curve and DSC traces are included in Figure S9. The 5% decomposition in the TGA thermogram of **P(FDPP-TP)** polymer was observed until 160 \({}^{\circ}\)C temperature, which may be due to adsorbed solvent molecules on the surface of the polymer, whereas the onset of melting was observed at 262 \({}^{\circ}\)C in the heating cycle of the DSC, reflecting the possible crystalline nature of the polymer. The OFET performance of **P(FDPP-TP)** was studied with both BGBC and BGTC device architectures, and **P(FDPP-TP)** polymer showed p-type OFET characteristics. A summary of the OFET performance for BGBC devices is shown in Table S2, and the corresponding transfer and output curves are presented in Figure 3. The hole mobilities were calculated from the transfer curves obtained at different annealing temperatures. For BGBC devices, maximum hole mobility of 4.46 \(\times\) 10\({}^{-3}\) cm\({}^{2}\) V\({}^{-1}\) s\({}^{-1}\) was measured, and the on/off ratio was \(\sim\)10\({}^{3}\), without thermal annealing treatment. After annealing at 150 \({}^{\circ}\)C for 5 min,  
Figure 2: (a) UV-Vis spectrum; (b) Cyclic voltammogram of **P(FDPP-TP)**. the hole mobility showed a 10-fold increase compared to the value measured for non-annealed devices. Once the annealing temperature was increased to 200 \({}^{\circ}\)C, the maximum hole mobility had a value of 0.42 cm\({}^{2}\) V\({}^{-1}\) s\({}^{-1}\), and the on/off ratio also increased to 10\({}^{5}\). This improvement is similar to reported DPP polymers in the literature [27, 39, 44, 45]. At low annealing temperatures, the threshold voltages varied between \(-2\) and \(-7\) V. The temperatures higher than 200 \({}^{\circ}\)C resulted in a reduction in the hole mobility, which may be due to the thermal degradation of the polymer suggested by the TGA data. The BGTC devices showed the same trend in the hole mobility, and the maximum mobility obtained was 0.127 cm\({}^{2}\) V\({}^{-1}\) s\({}^{-1}\) at 200 \({}^{\circ}\)C. Corresponding transfer and output plots are shown in Figures S7 and S8. A summary of the OFET parameters is included in Table S3. For the BGTC devices, the maximum mobility measured was 2.62 \(\times\) 10\({}^{-3}\) cm\({}^{2}\) V\({}^{-1}\) s\({}^{-1}\) at room temperature. Upon annealing, it showed an increase of \(\sim\)100-fold at 200 \({}^{\circ}\)C, retaining the on/off ratio higher than 10\({}^{5}\), indicating that intrinsic hole mobility is independent of the device architecture used. The optimized conditions for both the device architectures showed better device performance concerning hole mobility and on/off switch-ratio than our previously reported **PDPP-TP** polymer with the thiophene spacer group [26]. The **PPPP-TP** showed four times higher maximum hole mobility compared to the maximum mobility reported for **PDPP-TP**), and the on/off ratio was 10\({}^{2}\) times higher than that of **PDPP-TP**. The transfer curves of the devices showed improved \"linear\" behavior upon annealing. They showed two gradients at lower temperatures, but the transistors reached the nearly ideal behavior leading to \"linear\" plots for both BGBC and BGTC devices for the annealed films. For most of the DPP-based polymers, the mobility calculation has suffered from the non-ideal behavior of the transfer curves [25, 26, 31, 33], and the transistor behavior of TP-based polymers has shown its ability to be utilized as a better candidate for improved OFET applications. Moreover, the spacer unit's change from thiophene to furan in DPP copolymers with thienylenevinylene (TVT) has dramatically increased the hole mobility of furan-based DPP, a promising building block for a vast range of semiconducting polymers for organic electronics [40, 41].