Encapsulation of colloid perovskite nanocrystals into solid polymer matrices: Impact on electronic transition and photoluminescence

To improve the stability and enable luminescent devices, colloidal perovskite nanocrystals (NCs) are usually encapsulated by polymer host matrices. Here, colloidal CsPbX3 (X = Cl, Br or I, or mixture) NCs with bright emissions covering wide color gamut (similar to 410-700 nm) are incorporated into the off-stoichiometry thiol-ene (OSTE) for solid state luminescence. The impact of polymer encapsulation on electronic transitions is investigated by comparison of absorption, photoluminescence (PL), and time resolved PL (TRPL) of the CsPbX3 NCs before and after the encapsulation by the OSTE. The PL bandwidth increase pronouncedly, while the PL peak position apparently blue shifts after encapsulation. The spectral changes suggest the energy transfer between the CsPbX3 NCs and OSTE matrix and decreased exciton binding energy due to the suppressed dielectric screen effect, which are further validated by the TRPL results. This work sheds light on the fluorescence of CsPbX3 NCs incorporated in the polymer host matrices, which will facilitate their future applications in light-emitting and other optoelectronic devices.