Controllable Growth of Perovskite Films by Room‐Temperature Air Exposure for Efficient Planar Heterojunction Photovoltaic Cells. (21st October 2015)

• Record Type: Journal Article
• Authors: Yang, Bin; Dyck, Ondrej; Poplawsky, Jonathan; Keum, Jong; Das, Sanjib; Puretzky, Alexander; Aytug, Tolga; Joshi, Pooran C.; Rouleau, Christopher M.; Duscher, Gerd; Geohegan, David B.; Xiao, Kai
• Is Part Of: Angewandte Chemie. Volume 127:Number 49(2015)
• Page Start: 15075
• Page End: 15078
• Publication Date: 2015-10-21
• Subjects: Dünne Filme -- In‐situ‐Röntgenbeugung -- Luft -- Perowskite -- Photovoltaik; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.201505882
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: A two‐step solution processing approach has been established to grow void‐free perovskite films for low‐cost high‐performance planar heterojunction photovoltaic devices. A high‐temperature thermal annealing treatment was applied to drive the diffusion of CH3 NH3 I precursor molecules into a compact PbI2 layer to form perovskite films. However, thermal annealing for extended periods led to degraded device performance owing to the defects generated by decomposition of perovskite into PbI2 . A controllable layer‐by‐layer spin‐coating method was used to grow "bilayer" CH3 NH3 I/PbI2 films, and then drive the interdiffusion between PbI2 and CH3 NH3 I layers by a simple air exposure at room temperature for making well‐oriented, highly crystalline perovskite films without thermal annealing. This high degree of crystallinity resulted in a carrier diffusion length of ca. 800 nm and a high device efficiency of 15.6 %, which is comparable to values reported for thermally annealed perovskite films. Abstract : An der „frischen Luft"︁ und bei Raumtemperatur kommt es zur Diffusion zwischen Schichten aus Perowskit‐Vorstufen und zur Bildung gut ausgerichteter, hochkristalliner dünner Perowskit‐Filme. Funktionseinheiten mit/ohne TiO2 ‐Elektronentransportschicht erreichten Effizienzen von 15.6 % bzw. 13.8 %.