Loss Analysis of Fully‐Textured Perovskite Silicon Tandem Solar Cells: Characterization Methods and Simulation toward the Practical Efficiency Potential

Abstract

Optimally enhancing the performance of perovskite silicon tandem solar cells comes with accurate identification of loss origins in the device in combination with optoelectrical device simulations assessing the respective efficiency gains to prioritize optimization pathways. Herein, various characterization methods, namely, spectrally resolved photoluminescence (PL), transient‐PL, PL‐based implied open‐circuit voltage (iVOC) imaging, spectrometric characterization, and Suns‐VOC measurements are combined to quantify current density–voltage (jV) photovoltaic metric losses of a fully‐textured perovskite silicon tandem solar cell (26.7% efficiency). The extracted device characteristic parameters are then used as a reference for the comprehensive optoelectrical Sentaurus simulation model which precisely reproduces the experimentally obtained optical and electrical solar cell characteristics, considering mobile ion dynamics. Subsequently, starting from the current device design, the authors alleviate one step at a time the loss constraints and show the impact of each loss channel on the efficiency, the impact of each loss channel on the efficiency, identifying the three major ones to be at the: 1) perovskite/C60 interface (−4.6%abs) , 2) the series resistance (−2.9%abs), and 3) light management (−2.1%abs), which limit the VOC, fill factor, and jSC of the device, respectively. Furthermore, it is demonstrated that a practical efficiency potential of 39.5% can be regarded as a practical limit for the presented tandem device architecture.

Optoelectrical Modeling of Perovskite/Perovskite/Silicon Triple‐Junction Solar Cells: Toward the Practical Efficiency Potential

“…In a former publication, we analogously showcased the impact of mitigating each individual loss channel step by step for a PS tandem solar cell based on a variety of measurements with different characterization methods. [ 11 ] However, for the PPS cell, this experimental work and establishing equivalent characterization methods is ongoing; therefore, due to the lack of experimental data, we cannot yet assign values to the individual contributions. In Figure , a band diagram at the maximum power point of the simulation of the cell in the practical potential scenario with idealized electrics is shown.…”

“…An efficiency of 44.3% represents a 51% rel increase over the potential of the silicon single cell with 29.4% [ 30 ] and 11% rel improvement over the PS tandem cell with 39.3%. [ 11 ]…”

“…For modeling, we use Sentaurus TCAD, [10] a tool that has already demonstrated its capability in accurately describing the optical properties of PS tandem solar cells. [11][12][13] In this study, we extend the model to the triple-junction solar cell, which includes an additional perovskite absorber layer with ETLs/HTLs. To account for the different bandgaps in the top and middle perovskite layers, we need to approximate the nk-data, due to the lack of experimental data.…”

“…To translate the individual steps into efficiency potentials, an electrical simulation model in Sentaurus TCAD [ 10 ] was elaborated for this triple‐junction technology for the first time including the ion migration within both perovskite absorbers. As experimental characterization of the device is an ongoing process, this article is restricted on idealized electrical properties, which allow us to yield a practical efficiency potential for PPS solar cells analogously to a previous publication by Er‐Raji et al [ 11 ] . Full electrical simulation and experimental validation of the current PPS solar cell remain for future work.…”

“…(silicon),[29] (PS tandem),[27] (PPS),[26] (all perovskite); practical potential values from ref [30]. (silicon),[11] (PS tandem), and this work (PPS); theoretical limit from refs [2,31]…”