## 4 Conclusions  
In summary, we compared three post-deposition processing treatments using DPP(TBFu)2:PC61 BM as a model system. First, we determined that the decrease in PCE in flexible ITO-PET substrates was mainly due to the characteristics of the ITO film. Therefore, we consider it of high importance to find new flexible architectures that conjugate the ITO properties while maintaining the mechanical qualities of the substrate. Then, we tested several post-deposition processing treatments for the active layer, among which JHA is described for the first time for the annealing of the photoactive layer in this kind of device. On one hand, TA and SVA are widely used techniques and showed comparable efficiency results in this work. However, the testing of several exposure times and additional characterization is required to optimize device fabrication. On the other hand, the application of JHA provides a precise temperature treatment that has allowed us to tune the regular thermal annealing processing and increase the PCE of the devices (50% higher). Moreover, it is readily applied and has given excellent results in shorter times in comparison to the other two techniques.  
Finally, we believe that these results can be of interest for the post-deposition treatment of larger-area devices, especially the JHA treatment, since it is applied in in-operand conditions. With JHA, the improvement in the photoactive domains can be monitored in real time, allowing for easier optimization during the device fabrication process.  
The following are available online at [[https://www.mdpi.com/article/10.3390/app12052552/s1](https://www.mdpi.com/article/10.3390/app12052552/s1)]([https://www.mdpi.com/article/10.3390/app12052552/s1](https://www.mdpi.com/article/10.3390/app12052552/s1)), Figure S1. J-V curve of the reference cell with the following structure: glass/ITO/PEDOT:PSS/active layer/LiF/Au. Figure S2. Photographs of DPP(TBFu)2:PCBM films as-casted (blue) and after SVA treatment (purple) made in a close home-made system. Figure S3. (a). AFM images and (b) roughness profile of a sample overexposed to a SVA treatment. Figure S4. Absorption spectra of as-cast and solvent vapour annealed devices on glass for different times when using (a) DCM and (b) THF. Figure S5. (a) J-V curves of a flexible device under JHA treatment from as-cast to 90 minutes and (b) image taken by a thermal camera during the application of the JHA on a solar cell.  
Conceptualization, M.M., E.M.-F. and E.P.; methodology M.M., D.F., A.V.; validation M.M., D.F., A.V., E.M.-F. and E.P., writing - original draft, review and editing M.M., D.F., A.V., E.M.-F., E.P., Supervision E.M.-F., E.P. All authors have read and agreed to the published version of the manuscript.  
This research was funded by Eurecat, ICIQ, ICREA and AGAUR grant number 2017-SGR-978.  
**Institutional Review Board Statement:** Not applicable.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Temperature** & **V\({}_{\text{oc}}\) (V)** & **J\({}_{\text{sc}}\) (mA/cm\({}^{2}\))** & **FF (\%)** & **PCE (\%)** & **R\({}_{\text{S}}\) (f)** & **R\({}_{\text{P}}\) (f)** \\ \hline
110 \({}^{\circ}\)C & 0.64 & 3.11 & 36.82 & 0.73 & 469.63 & 2133.71 \\
65–80 \({}^{\circ}\)C & 0.77 & 6.14 & 31.36 & 1.46 & 330.363 & 837.98 \\ \hline \hline \end{tabular}
\end{table}
Table 4: Comparison of solar cell parameters of flexible devices annealed at different temperatures.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** Not applicable.  
**Acknowledgments:** The authors acknowledge funding from Eurecat, ICIQ, and ICREA. AGAUR is also acknowledged for financial support through project 2017-SGR-978.  
**Conflicts of Interest:** The authors declare no conflict of interest.