Showerhead-assisted chemical vapor deposition of CsPbBr_3 films for LED applications

摘要

CsPbBr_3 represents a highly attractive material for perovskite light-emitting diodes (PeLEDs) in the green spectral range. However, the lack of deposition tools for reproducible and scalable growth of perovskite films is one of the major obstacles hindering PeLED commercialization. Here, we employ the highly scalable showerhead-assisted chemical vapor deposition (CVD) method to produce uniform pinhole-free CsPbBr_3 films for PeLED application. The precursors CsBr and PbBr_2 are evaporated under low vacuum in N_2 carrier gas. By adjusting the PbBr_2 sublimation temperature, process conditions for CsBr-rich, stoichiometric, and PbBr_2-rich CsPbBr_3 layer growth have been developed. A substrate temperature of 160°C enables direct growth of these CsPbBr_3 films on a polymeric hole transport layer (HTL), finally yielding PeLEDs with a maximum luminance of 125 cd/m~2. Although the device efficiency still lags behind solution-processed counterparts, our approach presents the first demonstration of PeLEDs containing CsPbBr_3 films processed in a perovskite showerhead-assisted CVD reactor.