Stability issues and recovery strategies for perovskite/silicon

tandem solar cells

Mengmeng Chu¹, Maha Nur Aida², Alamgeer¹, Hyejeong Jin³, Hasnain Yousuf¹, Rafi ur Rahman³, Xiaowei Li⁴, Jinli Yang⁴, Zijia Li⁴, Muhammad Quddamah Khokhar³, Junsin Yi^1,2,3*

¹Interdisciplinary Program in Photovoltaic System Engineering, Sungkyunkwan University,

Republic of Korea

²Department of Future Energy Engineering, Sungkyunkwan University, Republic of Korea

³Department of Electrical and Computer Engineering, Sungkyunkwan University, Republic of Korea

⁴Chint New Energy R&D Center, Frontier Technology Dept.

^*E-mail: junsin@skku.edu

Abstract

Perovskite/silicon (PVK/Si) tandem solar cells have surpassed the crystalline silicon efficiency limit (29.4%), with our two terminal devices reaching a certified 31.50%, but long-term stability remains a key hurdle. Existing IEC tests target crystalline silicon and neglect tandem metastability, mobile ion migration and hysteresis. We examine five issues: pretreatment, hot spot, UV, electrical bias and potential induced degradation (PID), and review proposed solutions. IEC MQT 19 stabilization (≥10 kWh/m², 50 ± 10°C) can under stabilize or over stress the perovskite, so we propose a 5-10 min maximum power point tracking soak at 25-45°C, extended until dP/dt ≈ 0. The IEC hot spot procedure causes unintended degradation (>2% in cell selection, ~7% under short circuit exposure), whereas a fixed load voltage and exposure at the bypass diode turn-on voltage keep the final degradation below 5%. PID (-1000 V, 60°C) causes ~50% efficiency loss in one day through Na⁺ drift and Cs, Pb, I and Br out diffusion; a reported 50 nm NiO_x barrier raises efficiency retention from 27% to 65%. Under AM 1.5G illumination at 85°C, reversible ion migration (retention ≈80%) evolves into irreversible phase segregation (≈62%). An AC bias (square wave, 100 kHz, V_pp = 2 V) recovers 95-99% of the efficiency; TEM and photoluminescence analyses show a clear interface, cured defects and restored carrier lifetime. These results support in situ electro healing and tandem specific IEC tests.