Fabrication of nickel oxide composites with carbon nanotubes for enhanced charge transport in planar perovskite solar cells

초록

As the conductivity of metal oxides is often insufficient for use in inverted planar perovskite solar cells (PSCs), a hybrid hole transporter consisting of carbon nanotube (CNT)-embedded nickel oxide (NiOx) is suggested to enhance the conductivity. Fully solution-processed NiOx/CNT composites are prepared by introducing CNTs (0–20 vol%) into a NiOx solution. Raman spectroscopy confirms successful incorporation of the CNTs in the NiOx-based hybrid material. Also, enhanced conductivity of NiOx by introducing CNTs is confirmed by conductance measurement and conductive atomic force microscopy. Furthermore, the enhanced charge extraction properties of the NiOx/CNTs hybrid are evidenced by transient photocurrent, steady-state and time-resolved photoluminescence. Electrochemical impedance spectroscopy reveals a reduction in charge recombination when the hybrid material is used as the hole transport layer (HTL) in PSCs. Interestingly, the average power conversion efficiency (PCE) of the PSCs is increased from 13.1% to 15.1% by applying this hybrid HTL. The best-performing cell, using NiOx/CNTs (7.5 vol%), exhibits a PCE of up to 16.9%. This unprecedented HTL provides a fundamental method for enhancing the performance of inorganic charge transporters for solution-processed inverted planar PSCs. © 2020 Elsevier B.V.

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