| Popis: |
Nowadays, organic-inorganic hybrid perovskite solar cells have emerged rapidly in over few years due to their impressive improvements in the photoconvertion efficiencies exceeding 21%.1 This technology has become an alternative to the conventional photovoltaic devices, such as Silicon Solar Cells which consume a large portion of the market. In spite of their powerful features, for instance: high absorbance and long-range balanced charge transport lengths within hybrid perovskites,2 there are still some issues that are complete unknown. The electrical processes such as carrier transport into the perovskite film and charge extraction at the interfaces as well as electric field that occurs in the timescale of seconds are still under debate.3 Particularly, we found a new current peak at forward bias in the current-voltage curves under dark for the standard mesoscopic perovskite solar cells. This shape only appears at reverse scan (RS) direction and when the solar cells were kept for several seconds at short-circuit conditions before starting the RS measurement. If the device remains at forward conditions, the mentioned peak disappears. To that end, several hole transport materials (Spiro-OMeTAD and P3HT) and perovskite absorbers with different organic/inorganic cations (CH3NH3PbI3 and CsPbI3) were analyzed in a complete mesoporous-TiO2 photovoltaic devices. We considered that shallow and/or deep traps states located at interface either perovskite/p-type or perovskite/n-type transport materials should be filled. References 1 J. H. Noh, S. H. Im, J. H. Heo, T. N. Mandal, and S. I. Seok, Nano Lett. 13 (4), 1764 (2013). 2 B. Wu, K. W. Fu, N. Yantara, G. C. Xing, S. Y. Sun, T. C. Sum, and N. Mathews, Adv. Energy Mater. 5 (19), 8 (2015). 3 H. S. Duan, H. P. Zhou, Q. Chen, P. Y. Sun, S. Luo, T. B. Song, B. Bob, and Y. Yang, Phys. Chem. Chem. Phys. 17 (1), 112 (2015); X. D. Li, X. Y. Wang, W. J. Zhang, Y. L. Wu, F. Gao, and J. F. Fang, Org. Electron. 18, 107 (2015). |
