Performance of WO₃-Incorporated Carbon Electrodes for Ambient Mesoscopic Perovskite Solar Cells

Abstract

The stability of perovskite solar cells (PSC) is often compromised by the organic hole transport materials (HTMs). We report here the effect of WO3 as an inorganic HTM for carbon electrodes for improved stability in PSCs, which are made under ambient conditions. Sequential fabrication of the PSC was performed under ambient conditions with mesoporous TiO2/Al2O3/CH3NH3PbI3 layers, and, on the top of these layers, the WO3 nanoparticle-embedded carbon electrode was used. Different concentrations of WO3 nanoparticles as HTM incorporated in carbon counter electrodes were tested, which varied the stability of the cell under ambient conditions. The addition of 7.5% WO3 (by volume) led to a maximum power conversion efficiency of 10.5%, whereas the stability of the cells under ambient condition was ∼350 h, maintaining ∼80% of the initial efficiency under light illumination. At the same time, the higher WO3 concentration exhibited an efficiency of 9.5%, which was stable up to ∼500 h with a loss of only ∼15% of the initial efficiency under normal atmospheric conditions and light illumination. This work demonstrates an effective way to improve the stability of carbon-based perovskite solar cells without affecting the efficiency for future applications.

Electrochemical Impedance Spectroscopy Analysis of Hole Transporting Material Free Mesoporous and Planar Perovskite Solar Cells

“…Therefore, employing a 3-RC circuit model for this case is also justifiable. Both models have been used consistently in other works for double-layer mesoscopic architectures [25,29,[32][33][34][35][41][42][43][44]66]. The common reasoning provided for employing 2-RC elements in previous works is that, since the HTM layer is not present in the device, perovskite plays both roles of light-harvesting and hole transporting and, therefore, only two RC elements representing carbon/perovskite interface and perovskite/ETL interface are required to fit the EIS data.…”

“…EIS has been utilized in HTM-free PSC analysis to compare different architectures [31], different compositions [29], and different thicknesses of the layers [43] by studying their interfacial properties. Below, we describe some of the ways that researchers have adopted to utilize the EIS tool in their studies.…”

“…Royal Society of Chemistry, 2014. (c) Reproduced with permission from[29]. American Chemical Society, 2020.…”

Perovskite Solar Cells for BIPV Application: A Review

“…85% of initial PCE retains after 500 h in the ambient condition in the presence of light [109] Degradation of perovskite is the main reason for instability as mentioned above. Poor thermal stability over a long period and also the humidity related adverse effects contribute towards the degradation of the Pb-based perovskite [63,64,92].…”

High-performance hole conductor-free perovskite solar cell using a carbon nanotube counter electrode

“…[13][14][15] In the past few years, carbon substances such as carbon black, bio-carbon, bulk and ultrathin graphite, and carbon nanotubes, with an energy alignment comparable to that of gold, have been employed in carbon-based PSCs. [16][17][18][19] Previously, Ku et al reported the fabrication of fully printable processed mesoscopic perovskite/titanium dioxide (TiO 2 ) HTM-free PSCs with carbon CE. Employing a common dropcoating method to inltrate the perovskite into three mesoporous materials showed a device PCE of 6.65%.…”