Mitigation of Current Mismatch Limitations and Spectral Variation Losses Using Three-Terminal Perovskite–Silicon Tandem Solar Cells

Mohammad Gholipoor^1,2, Michael Rienaecker³, Xuzheng Liu^1,2, Seyedamir Orooji^1,2, Lingyi Fang^1,2, Paul Fassl^1,2, Renjun Guo^1,2*, Uli Lemmer^1,2, Robby Peibst³*, and Ulrich Wilhelm Paetzold^1,2*

¹Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology (KIT), Germany

²Light Technology Institute (LTI), Karlsruhe Institute of Technology (KIT), Germany

³Institute for Solar Energy Research in Hamelin (ISFH), Germany

mohammad.gholipoor@kit.edu

ABSTRACT

Two-terminal (2T) Perovskite/silicon tandem solar cells (PSTSCs) have emerged as a leading candidate for next-generation high-efficiency photovoltaics [1,2]. However, challenges such as instability and current mismatch under realistic operation conditions restrict their commercial development [3]. Although four-terminal (4T) PSTSCs can alleviate the above limitations, they have disadvantages such as higher cost, complexity of electrical interconnection, inactive areas due to laser scribing [4], and significant parasitic absorption losses occurring in the thick transparent conductive oxide layer [5].

Three-terminal (3T) tandem architectures offer potential solutions to these limitations [6]. Here, we demonstrate that three-terminal (3T) perovskite/silicon tandem solar cells effectively mitigate weather-dependent performance variations and current mismatch under real-world operating conditions. We report a power conversion efficiency (PCE) of 30.1% in 3T tandem cells using a front-side textured, interdigitated back contact (IBC), and passivated POLysilicon-on-silicon Oxide (POLO) silicon bottom cell. Through a comparative analysis of two-terminal (2T) and three-terminal (3T) device configurations using an iterative measurement technique, we demonstrate that the 3T architecture is independent of the perovskite bandgap. While the PCE of 2T PSTSCs decreases by about 7% as the perovskite bandgap drops from 1.72 to 1.52 eV, the PCE of 3T solar cells remains relatively stable. Such flexibility overcomes the limitations of fixed-bandgap halide perovskites, allowing the use of more stable bandgaps.

Furthermore, 3T devices appear to be more robust to variations in the solar spectrum, particularly when the tandem cell’s short-circuit current density is limited by the top cell. Numerical simulations show that 3T solar cells deliver higher annual energy yield (EY) than 2T devices under various climates, confirming their greater robustness to spectral variations. These findings highlight the potential of 3T architectures to address key challenges in tandem photovoltaic technology, facilitating their widespread adoption in industrial and real-world applications. The full results of this study have recently been published in Advanced Science [7].