Needle coke: A predominant carbon black alternative for printable triple mesoscopic perovskite solar cells

As a key component of a printable triple mesoporous perovskite solar cell (PSC), the carbon material used in it is a decisive factor for the photovoltaic performance of the device. In this work, needle coke (NC) has been innovatively introduced into the carbon paste to replace the traditional carbon black for the fabrication of printable triple mesoporous PSCs. The champion power conversion efficiency was largely improved from 7.49% with carbon black to 11.66% with NC. The excellent performance of NC can be attributed to its high charge extraction capability, morphology-assisted perovskite injection and crystallization, inhibition of current leakage, and charge recombination. In addition, its low dielectric constant is also beneficial to minish the hysteresis effect for PSCs. (C) 2019 Elsevier Ltd. All rights reserved.