Twin domains modulate light-matter interactions in metal halide perovskites

Despite the extensive insights gained in how the microstructure impacts the device performance of metal halide perovskites (MHPs), little is known about the effect of the ferroelastic twin domains on the optoelectronic properties of MHPs. In this work, the effect of the ferroelastic twin domains on the photoluminescence (PL) behavior of CH3NH3PbI3 is investigated by correlating measurements from multiple microscopies. PL spectra and the confocal PL lifetime maps reveal no difference in wavelength of emitted light and decay dynamics between the neighboring domains, whereas PL intensity is different. We propose that the PL intensity variation is induced by the difference in light-matter interactions between neighboring domains. These results suggest that the effect of ferroelastic twin domains on the intrinsic PL behavior is negligible. We expect that this work will stimulate researchers to further explore the impact of twin domains on the photophysical properties of MHPs.