What question did this study set out to answer?

To investigate strategies to enhance the open-circuit voltage of wide-bandgap perovskite solar cells through defect passivation and energy-level engineering.

February 2, 2026Open Access

Cooperative Dipole Engineering Unlocks 92.8% Shockley–Queisser Voltage Limit in Wide-Bandgap Perovskites for Tandem Photovoltaics

Key Points

To investigate strategies to enhance the open-circuit voltage of wide-bandgap perovskite solar cells through defect passivation and energy-level engineering.
Developed a coassembly technique using acetylcholine chloride and n-octylammonium iodide for surface treatment.
Measured voltage, current density, fill factor, and power conversion efficiency of treated perovskite solar cells.
Integrated the optimized solar cell into a tandem configuration with p-type silicon.
Achieved an open-circuit voltage of 1.29 V and a power conversion efficiency of 21.27% in wide-bandgap perovskite solar cells.
The tandem configuration reached a power conversion efficiency of 26.8% with an open-circuit voltage of 1.91 V.
Demonstrated that cooperative defect passivation significantly improved device performance up to 92.8% of the Shockley–Queisser voltage limit.

Abstract

Wide-bandgap (WBG) perovskite solar cells (PSCs, Eg ≃ 1.67 eV) still suffer from pronounced open-circuit-voltage (VOC) deficits. Here, we report a synergistic surface-passivation strategy that coassembles a dipolar quaternary-ammonium salt, acetylcholine chloride (ACCl), with an electron-rich long-chain alkylammonium halide, n-octylammonium iodide (OAI). A mixed ACCl:OAI treatment reconstructs the perovskite surface, lowers surface-trap density, and aligns the valence band with the hole-transport layer. Consequently, the champion WBG PSC delivers VOC = 1.29 V, JSC = 20.0 mA cm–2, FF = 82.8%, and PCE = 21.27%, corresponding to 92.8% of the Shockley–Queisser voltage limit. When integrated as the top absorber in a monolithic n-i-p perovskite/p-type Si tandem, the passivated WBG cell contributed to a PCE of 26.8% with a VOC of 1.91 V. These results reveal that cooperative defect passivation and energy-level engineering are both essential to unlock the full voltage potential of WBG perovskites.

Cooperative Dipole Engineering Unlocks 92.8% Shockley–Queisser Voltage Limit in Wide-Bandgap Perovskites for Tandem Photovoltaics

Key Points

Abstract

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