This paper presents a new approach to improve the efficiency of wide bandgap perovskite solar cells. The team developed a new self-assembled monolayer, (4-(5,9-dibromo-7H-dibenzo[c,g]carbazol-7-yl)butyl)phosphonic acid (DCB-BPA), as a selective hole transport layer in the 1.77 eV bandgap perovskite absorber. This innovation led to a significant increase in average open-circuit voltage (VOC) from 1.18 V to 1.31 V, achieving a record VOC of 1.339 V. The improved interface quality and energy level alignment reduced non-radiative recombination. The champion devices in this study realized a conversion efficiency of 18.88%, enabling highly efficient 4-terminal all-perovskite tandem solar cells with 26.9% efficiency.

In this study, four Enlitech products played an important assisting role: REPS Voc loss analysis system, QE-R quantum efficiency measurement system, and SS-F5-3A solar simulator. These tools provided critical measurements and simulations to support the research findings. The REPS Voc loss analyzer from Enlitech was crucial for electroluminescence measurements, able to detect extremely low EL-EQE signals and calculate thermodynamic Voc, radiative Voc, and non-radiative recombination Voc. The QE-R quantum efficiency system delivered highly repeatable and accurate results, enabling rapid IPCE, IQE and spectral response measurements. The SS-F5-3A solar simulator achieved reliable J-V curve recordings under simulated solar illumination. By utilizing these precision measurement and simulation tools, the researchers obtained reliable conclusions.

Keywords: perovskite solar cell, VOC loss