Fig. 2

Perovskite MQW films deposited on PEIE modified ZnO layers. a Absorption spectra of NFPI7 films upon various annealing time. b XRD data of FAPbI3, ZnO/PEIE, and NFPI7 films upon various annealing time. c PL spectra of NFPI7 films excited by a 445 nm laser. d Time-resolved photoluminance of NFPI7 films annealed for various time. e Excitation-intensity-dependent PLQE of MQW perovskite films upon various annealing time. The most efficient emission is from the 10 min film which is around 60%