**4. Conclusions**

Toxicity and stability are the main hurdles for the commercialization of the perovskite solar cell. For this purpose, a planar p-i-n type perovskite solar cell is proposed, and the stability is improved by the proper selection of doping-free hole-transport (NPB) and electron-transport layer (PCBM). On the other hand, to avoid toxicity a novel leadfree perovskite compound cesium titanium (IV) bromide (Cs2TiBr6) is incorporated as the absorber layer and finally the Ag/BCP/PCBM/Cs2TiBr6/NPB/ITO solar cell was proposed as the lead and dopant free perovskite solar cell. For photovoltaic characterization, we theoretically analyzed, and optimized the proposed solar cell with the help of SCAPS 1D. After a comprehensive optimization of each layer, it is observed that the proposed perovskite solar cell can yield with maximum power-conversion efficiency up to 16.85%. We believe that the outcome of this study will help in the fabrication of lead and dopant free highly efficient and stable perovskite solar cell for future applications.

**Author Contributions:** S.A.M. and A.N.M.A. contributed equally for the conceptualization, methodology, validation, formal analysis, and writing of the manuscript. All authors have read and agreed to the published version of the manuscript.

**Funding:** The authors would like to thank the Deanship of Scientific Research at Umm Al-Qura University for supporting this work by grant code 18-ENG-1-01-0005.

**Acknowledgments:** The authors acknowledge the use of SCAPS-1D program developed by Marc Burgelman et al. at the University of Gent for all the simulations reported in this work.

**Conflicts of Interest:** The authors declare no conflict of interest.
