Transparent conducting oxide-free and Pt-free flexible dye-sensitized solar cells employing CuS-nanosheet networks as counter electrodes

Abstract

We present completely transparent conducting oxide (TCO)-free and platinum (Pt)-free flexible dye sensitized solar cells (DSSCs) with remarkable efficiency and superior mechanical flexibility, consisting of TiO₂ nanotube arrays on Ti foil (TNARs/Ti) as the photoanode and newly designed free-standing copper sulphide nanosheet (CuS NS) networks as the counter electrode (CE). Herein, CuS NS networks not only served as conducting films, but also as catalysts for DSSCs. CuS NS network electrodes exhibit both excellent optoelectronic performances (a sheet resistance of 20 Ω sq⁻¹ at 80% transmittance) and remarkable mechanical stability under bending tests compared to traditional ITO/plastic substrates. What is more, the electrochemical catalytic activity of CuS NS networks towards triiodide solution was first investigated and 6.38% energy conversion efficiency was obtained by using CuS NS networks as the CE.