Evolutions of the optical properties in green-emitting MAPbBr3 perovskite nanoplatelets/polymethyl methacrylate (PMMA) composite films for light-emitting diode applications

Organometal halide perovskites have been gaining tremendous attention for their potential application as optoelectronic devices, owing to their excellent optical and electronic properties. This work fabricated MAPbBr3/PMMA composite film with bright green emission via a simple drop-casting method. It is found that when MAPbBr3 were combined with PMMA, PL peak position and edge absorption spectra exhibit a redshift phenomenon. Comprehensive characterizations using x-ray diffraction (XRD) and transmission electron microscope (TEM) suggested that this phenomenon possibly corresponded to the dielectric screening and strain of perovskite crystal induced by the presence of PMMA. Understanding this redshift phenomenon could be beneficial for developing high color purity optoelectronic devices. A potential application of the prepared film as a green down-converter is also demonstrated. Applying the MAPbBr3/PMMA film on a UV LED has successfully generated green color at (0.21, 0.71), close to the green color standards, i.e., NTSC 1953 and Adobe RGB 98. This result suggests that MAPbBr3 perovskite nanoplatelets/PMMA composite films have great potential for light-emitting device applications.