A Thienothiophene-Based Cation Treatment Allows Semitransparent Perovskite Solar Cells with Improved Efficiency and StabilityAdvanced Functional MaterialsPaperBahri E. Uzuner / Cevahir C. Akgul / Esra Bag Celik / Gorkem Gunbas / Hava Z. Kaya / İlker Yildiz / Mehmet KOÇ / Milad Ghasemi / Mohsen Ameri / Selçuk YERCİ / Ümmügülsüm ŞahinA Thienothiophene-Based Cation Treatment Allows Semitransparent Perovskite Solar Cells with Improved Efficiency and Stability