**6. Concluding remarks**

New materials have emerged as an appealing and profitable replacement to inorganic semiconductors due to the desire to manufacture more cost-effective electronic devices using simple manufacturing processes. Organic materials, such as conjugated polymers, tiny organic molecules, and self-assembling organic semiconductors, have recently piqued interest due to their ability to fabricate flexible, lightweight, semi-transparent, and large-area devices. As a result, DFT based computational computations have become a valuable method for investigating materials in OSC research. The relevance of DFT calculations in the knowledge of the structureproperties relationship in the design of new polymer solar cells has been highlighted in this paper. Furthermore, we discovered that DFT's improved power in understanding and forecasting features of polymer solar cells is caused by increased computational capacity and the emergence of robust and diverse computational methodologies. We have explored how theoretical calculations based on the KohnSham energy levels of density functional theory combined with Scharber's model can be utilized to locate viable photovoltaic polymers in this paper.

Within the generalized Kohn–Sham formalism that offered proper excitation energies, density functional theory and its time-dependent extensions made substantial progress along the range separated hybrid functionals. DFT has been effectively used to explain and predict molecular geometries, electronic structure, frontier molecular orbital (FMO) energy levels, absorption spectra, and intramolecular charge transfer for known conjugated organic compounds (ICT). These characteristics significantly impact the open-circuit voltage (VOC), short-circuit current (JSC), charge separation at the donor/acceptor interface, and solar photon absorption.
