ACS Energy Letters published a study in September 2022. As the perovskite field continues to develop, there are still issues to overcome in the process. Defects impair the stability of perovskite solar modules (PSMs) and exacerbate the photodegradation processes under continuous illumination (especially, UV light). Photodegradation is the gradual oxidation of organic matter to low-molecular intermediates under the action of light, eventually producing carbon dioxide and water and other ions. This will limit the competitiveness and commercial development of perovskite photovoltaics.

　　Here the researchers propose a tautomeric passivation strategy toward molecular isomerism passivation, 2,3-bis(2,4,5-trimethyl-3-thienyl)maleimide (DAE), to assist in the defect passivation of photostable PSMs with sustainable UV protection. After UV irradiation, the tautomeric DAE molecule in the perovskite film showed a high charge density difference values (-0.182e for -C=O-Pb; 0.015e for N-H…I-), and the defect formation energy was effectively improved , through the free closed and open rings of the DAE molecules in the PSM, preventing perovskite UV degradation. Enlitech’s Solar Simulator, QE-R Quantum Efficiency Measurement system and other instruments were used in this study to assist in the measurement. It was found that DAE PSCs exhibited champion efficiency and long-term UV photostability as high as 24.12% (small area: 0.08 cm²) and 18.47% (module area: 25 cm²). This also allows for continuous charging of the mobile phone on a cloudy day.

　　In addition to the EQE (External Quantum Efficiency) spectrum analysis of solar cells, the Quantum Efficiency Measurement System of Enlitech also provides Jsc (short-circuit current density) comparison for the short-circuit current of solar cells under the solar simulator to prove the authenticity of the experiment.