Photoluminescence of I‐VII Semiconductor Compounds. Sensitized Luminescence from “Deep States” Recombination in CuBr/AgBr Nanocrystals

Abstract

The photoluminescence (PL) properties of CuBr and CuBr/AgBr semiconductor nanocrystals (NCs) embedded in borosilicate glasses are measured under band‐to‐band excitation by a 355‐nm Nd YAG laser. We observed emission from CuBr (peaked at 520 nm) doped glass, which is associated with deep states in CuBr NCs. We also observed the sensitized blue to orange‐red emission in CuBr/AgBr‐glass systems (peaked at 520 and 570 nm), in which the luminescence intensity of CuBr decreases with increasing AgBr concentrations, while it is enhanced significantly around 570 nm. The results are discussed by the possible energy transfer between them, or by the multi‐exitonic recombination process which ejects an excited carrier from CuBr to AgBr NCs.

Cuprous halides semiconductors as a new means for highly efficient light-emitting diodes

“…The strong excitonic effects manifested by Re q k (0) in Fig. 2 agree at least qualitatively with the experimental results 32 33 34 .…”

“…Recently, I-VII γ -cuprous halides semiconductors 20 such as CuCl, CuBr, and CuI have drawn attention 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 because these are zincblende direct band-gap semiconductors (3.3 eV for CuCl, 2.91 eV for CuBr and 2.95 eV for CuI) and have large exciton binding energies (190 meV for CuCl, 108 meV for CuBr and 58 meV for CuI) with their lattice constants closely matched to that of Si as can be seen by the table 1 . From this table, one can see that the lattice constant of Si, 0.543 nm, is very closely matched to that of CuCl, 0.542 nm.…”