Enhancement of photocurrent extraction and electron injection in dual-functional CH₃NH₃PbBr₃ perovskite-based optoelectronic devices via interfacial engineering

Photocurrent extraction and electron injection in CH₃NH₃PbBr₃ (MAPbBr₃) perovskite-based optoelectronic devices are both significantly increased by improving the contact at the PCBM/MAPbBr₃ interface with an extended solvent annealing (ESA) process. Photoluminescence quenching and x-ray diffraction experiments show that the ESA not only improves the contact at the PCBM/MAPbBr₃ interface but also increases the crystallinity of the MAPbBr₃ thin films. The optimized dual-functional PCBM-MAPbBr₃ heterojunction based optoelectronic device has a high power conversion efficiency of 4.08% and a bright visible luminescence of 1509 cd m^-2. In addition, the modulation speed of the MAPbBr₃ based light-emitting diodes is larger than 14 MHz, which indicates that the defect density in the MAPbBr₃ thin film can be effectively reduced by using the ESA process.