Green Solvent Polishing Enables Highly Efficient Quasi-2D Perovskite Solar Cells

摘要

Preferred crystalline orientationat the surface of quasi-2Dorganic-inorganichalide perovskites is crucial to promote vertical carrier transportand interface carrier extraction, which further contribute to deviceefficiency and stability in photovoltaic applications. However, looseunoriented and defective surfaces are inevitably formed in the crystallizationprocess, especially with the introduction of bulky organic cationsinto the quasi-2D perovskites. Here, a facile and effective surfacepolishing method using a natural-friendly green solvent, 2,2,2-trifluoroethanol,is proposed to reconstruct the surface. After solvent polishing, therandomly oriented phases containing trap sites on the surface aresuccessfully removed, and the compact vertical-oriented phases underneathare revealed with less defectiveness and better smoothness, whichgreatly facilitates carrier transport and interfacial charge extraction.Consequently, the green solvent polished devices show a boosting efficiencyof 18.38% with a high open-circuit voltage of 1.21 V. The devicesalso show improved storage and operational stability.

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