**Author details**

*Solar Cells - Theory, Materials and Recent Advances*

We have reported in this work a theoretical investigation on a D-A type copolymer and a D-π-A-π-D type small molecule based on CPDT derivatives as electron

*Scharber diagram for estimating the power conversion (PCE) efficiency of the studied compounds.*

The studied materials exhibited narrow band-gap energies with high planar structures governed by intra-molecular non-covalent interactions. The particular conjugated arrangement added to the dicyanomethylene Bridge groups has leaded to considerable intra-molecular charge transfer (ICT) within these molecules. The optical absorption spectra covered an interesting part of the solar spectrum which indicated that the studied molecules exhibit high light harvesting efficiency. The deep HOMO energy levels of these molecule encourage their application as donor materials in a BHJ-OSCs with the [70] PCBM as acceptor. The TDM analysis showed the ease dissociation of excitons within the considered materials at the first exited state that leads to enhance the photovoltaic properties. The PCEs, estimated

This study revealed that the reliability of the designed donor materials for developing efficient materials for BHJ OSCs. A molecular tuning based on these designed conjugated materials may enhance the donor materials efficiency in photovoltaic

This research was supported by the Ministry of Higher Education and Scientific

donor with BT or DPP as electron acceptor moiety.

using Scharber diagram, close to 10% were reached.

**76**

**4. Conclusion**

**Figure 9.**

applications.

**Acknowledgements**

Research, Tunisia.

Rania Zaier\* and Sahbi Ayachi\* Laboratory of Physico-Chemistry of Materials (LR01ES19), Faculty of Sciences of Monastir (FSM), Avenue of the Environment 5019 Monastir, University of Monastir, Tunisia

\*Address all correspondence to: rania.zaier02@gmail.com; ayachi\_sahbi@yahoo.fr

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