Effect of Surface Treatment by Chemical-Mechanical Polishing for Transparent Electrode of Perovskite Solar Cells

Sangmo Kim,Chung Wung Bark

doi:10.3390/en13030585

Abstract

Perovskite solar cells (PSCs) are usually fabricated by using the spin coating method. During the fabrication process, the surface status is very important for energy conversion between layers coated in the substrate. PSCs have multilayer-stacked structures, such as the transparent electrode layer, the perovskite layer, and a metal electrode. The efficiency and uniformity of all layers depend on the surface status of the transparent electrode coated on the glass substrate. Until now, etching methods by chemical processes have been introduced to make the substrate surface smooth and uniform by decreasing surface roughness. However, highly reactive chemical treatments can be harmful to the environment. In this study, we employed an eco-friendly chemical-mechanical polishing (CMP) process to ensure the fluorine-doped tin oxide (FTO) substrate is treated with a smooth surface. Before the perovskite layer and electron transport layer (ETL) are applied, the TiO2 layer is coated with the FTO substrate, and the surface of the FTO substrate is polished using CMP. As a result, the CMP-treated surface of the FTO substrate showed a smooth surface, and the PSCs with CMP treatment did not require conventional TiCl4 treatment.

Highlights

This research focuses on solar energy as the most sustainable energy due to its clean, abundant, and unlimited energy source
Compared to the bare cell, the efficiency of perovskite solar cells (PSCs) prepared with a smooth fluorine-doped tin oxide (FTO) substrate treated by chemical mechanical polishing (CMP) processes improves by 10%
It was confirmed that the smooth surface in the current in relation to the graph in Figure 9 can be attributed to the scattering and absorbance of light, enhancing the photovoltaic performance of the perovskite solar cells [26]

Summary

Introduction

This research focuses on solar energy as the most sustainable energy due to its clean, abundant, and unlimited energy source. Compared to silicon-based solar cells, perovskite solar cells (PSCs) based on organic–inorganic hybrid materials have been introduced to next-generation solar cells, with low-cost production, light weight, and flexible device applications [1,2,3,4] These types of organic–inorganic-materials-based solar cells are usually fabricated by using the spin coating method. Since method is more pro-environmental than other chemically reactive treatments, it can reduce the this method is more pro-environmental than other chemically reactive treatments, it can reduce the adverse effects on the environment during the mass production of solar cells. The surface of the FTO substrate was smoothed by the chemical mechanical polishing (CMP) process, as compared to the TiCl4 treatment.

Surface Treatment

Fabrication of Perovskite Solar Cells to form CH3 NH

Measurements

Results and Discussion

Surface and cross-sections of of FE-SEM

Conclusions