Layer-controlled two-dimensional perovskites: synthesis and optoelectronics

Solution-processed hybrid organic-inorganic metal halide perovskites are emerging as one of the most promising candidates for low-cost photovoltaics and optoelectronics. Moreover, two-dimensional (2D) forms of these materials induce a dielectric quantum confinement effect that drastically increases the exciton binding energy. Previous studies on two-dimensional (2D) hybrid perovskites have been focused on the thinnest counterparts, namely, the zero-layer and monolayer species, in which the photoluminescence quantum yield is typically low (<10%), thereby limiting their applications in optoelectronics. Recent advances in colloidal synthesis have suggested that precise control over the layer numbers can be realized on a large scale, offering another degree of freedom in tailoring the optoelectronic properties. Herein, we reviewed the photophysical properties, synthetic routes, and potential technology opportunities of layer-controlled 2D hybrid perovskites.