Brightening thiocyanate-anion layered perovskite through internal stress modulated nano phase segregation

Thiocyanate-anion (SCN−) two-dimensional (2D) layered perovskite with internal stress-controlled nano phase segregation has been firstly demonstrated as a promising material system for luminescence applications. An interesting energy band structure is found as well as charge transfer process caused by nano phase segregation, which provide an alternative route to overcome the indirect-bandgap luminescence limit of SCN layered perovskites. It is revealed that, within the SCN layered framework, the segregated nano phases exist in a quantum well form, possessing much higher carrier localization and second-order radiative recombination abilities. With the help of internal stress modulation, these advantages can be significantly enhanced and finally contribute to high luminescence performances in visible-red regions. This work provides more potential opportunities for 2D layered perovskite materials in the future optoelectronic applications.