AUTHOR=Zhong Hong , Zhou Renlai , Wu Xiaoqing , Lin Xiaoyun , Wang Ya , Li Qian , Zhou Hang 

TITLE=Investigation of the S-Shaped Current–Voltage Curve in High Open-Circuit Voltage Ruddlesden–Popper Perovskite Solar Cells

JOURNAL=Frontiers in Energy Research

VOLUME=9

YEAR=2021

URL=https://www.frontiersin.org/journals/energy-research/articles/10.3389/fenrg.2021.689657

DOI=10.3389/fenrg.2021.689657

ISSN=2296-598X

ABSTRACT=<p>We report our investigation on the S-shaped current–voltage characteristics in a hot-casting–processed (BA)<sub>2</sub> (MA)<sub>3</sub>Pb<sub>4</sub>I<sub>13</sub> Ruddlesden–Popper (RP) perovskite solar cell. The two-dimensional perovskite solar cells are fabricated with NiO<sub>x</sub> as the hole transport layer (HTL), which leads to significantly high open-circuit voltage (V<sub>oc</sub>). The champion device shows a V<sub>oc</sub> of 1.21 V and a short current density (J<sub>sc</sub>) of 17.14 mA/cm<sup>2</sup>, leading to an overall power conversion efficiency (PCE) of 13.7%. Although the PCE is much higher than the control device fabricated on PEDOT:PSS, a significant S-shaped current–voltage behavior is observed in these NiO<sub>x</sub>-based devices. It is found that the S-shaped current–voltage behavior is related to the lower dimensional phase distribution and crystallinity at the bottom interface of the RP perovskite layer, and the S-shaped distortion is less severe after the device ageing test.</p>