The varied Magnetic polarons and related photoluminescence behaviors of layer PA2CdCl4: Fe (III) structure

Abstract Ferromagnetic polaron couplings (FMP) and antiferromagnetic polaron (AMP) couplings from the transition metal (TM) have been studied in zero dimensional or three dimensional photoluminescent structure. However, there is still some photoluminescence phenomena relate to FMP and AMP in photoluminescent layer structure are often overlooked. Based on this situation, we focus on layer PA2CdCl4: Fe (III) structure. In this work, we find out the doped Fe(III) ions easily replace the Cd-Cd pairs in the inorganic layer to form ferromagnetic Fe-Fe pairs in minor Fe ion doped PA2CdCl4 and varied magnetic Fe-Fe pairs in rich Fe ion doped PA2CdCl4. The ferromagnetic polaron couplings dominant the enhancement red emission in poor Fe ion doped layer PA2CdCl4 causing by the self-trapped exciton (STE) emission accidentally coincides with the emission of ferromagnetic (FM) Fe-Fe pairs. The varied magnetic polaron dominant one blue emission causing by the Zhang-Rice AFM state (Fe-Cl-Fe) together with the Fe-aniline charge-transfer band, the other one red emission come from FMP together with STE. The density functional theory (DFT) calculation result of FM and AFM PA2CdCl4: Fe (III) structure also proves 1) the direct Fe-Fe ferromagnetic coupling would overlap with the STE state from [CdCl6]4- cluster for favored red emission. 2) the electrons of N in aniline occupy Fe-3d orbitals formed the its transfer band and dominated in the blue emission processes. A bright blue light afterglow can also be observed from the PA2CdCl4:Fe(III) structure with rich antiferromagnetic polaron (AMP) couplings after UV lamp off, makes the PA2CdCl4:Fe(III) structure promising in the field of time-dependent photoluminescence. This work would help to understand the electronic structures, optical properties and photoluminescence behaviors of 2D magnetic semiconductors.