Mn2+ ions act as energy-transfer-stations of hot excitons (coupling-1) and couplers of cold excitons (coupling-2) to enhance charge-transfer exciton emission.
Excitons are created in Zn1−xMnxS under photo-excitation. A fraction of the excitons transfers their energy to ZnS's intrinsic traps, generating blue emission, whereas the remaining excitons are utilized to excite Mn2+ ions, showing orange emission.