Potential of TiO2 as a capping layer for industrial c-Si PERC solar cells

• Published in: Journal of computational electronics 2024-08, Vol.23 (4), p.874-883
• Main Authors: Siddiqui, Aamenah, Usman, Muhammad, Hallén, Anders
• Format: Article
• Language: English
• Subjects: Aluminum oxide; Atomic layer epitaxy; Atomic properties; Capping; Chemical vapor deposition; Contact pressure; Efficiency; Electrical Engineering; Emitters; Engineering; Mathematical and Computational Engineering; Mathematical and Computational Physics; Mechanical Engineering; Optical and Electronic Materials; Optical properties; Photovoltaic cells; Scratch resistance; Silicon; Simulation; Solar cells; Theoretical; Thickness; Titanium dioxide
• ISSN: 1569-8025; 1572-8137
• DOI: 10.1007/s10825-024-02187-0

Titanium dioxide (TiO 2 ) has gained popularity especially in photovoltaic applications, owing to its transparency in the visible region, and scratch resistance. In this work, the potential of TiO 2 as a capping layer for c-Si p-type SiN x passivated emitter and rear contact (PERC) solar cells is studied through extensive optical and device simulations. The bifacial PERC solar cell model used in this study is calibrated with an experimental device having an efficiency of 22.19%. Device simulation results show that TiO 2 deposited by the mesoporous technique outperforms atmospheric pressure chemical vapor deposition (APCVD) and atomic layer deposition (ALD)-based TiO 2 layers when capped over SiN x ( n  = 2.1) passivated solar cells. Furthermore, it is shown that the efficiency of SiN x ( n  = 2.1)/TiO 2 based solar cells is maintained, even when the TiO 2 layer thickness varies from 75 to 95 nm. To enhance the efficiency further, the type of SiN x layer (characterized by the n value), and the thicknesses of SiN x and TiO 2 layers are optimized simultaneously to find the best combination of these parameters. The best front side solar cell efficiency of 22.43%, is obtained when a stack of SiN x ( n  = 1.99)/TiO 2 ( t  = 58/76 nm) is used. Similarly, a rear side efficiency of 16.59% is achieved when the rear side Al 2 O 3 /SiN x stack is capped with mesoporous TiO 2 . These efficiencies are 0.24 and 1.25% higher, respectively, when compared to the original SiN x passivated PERC solar cell, demonstrating the prospective of using TiO 2 in encapsulant-free commercial photovoltaic applications.