Effect of Tm Doping on the Magnetic, Electronic and Optical Response Properties of TiO2 for Organic Solar Cell Application: A Density Functional Theory Study

The magnetic field contribution to charge transfers of active layer materials for organic solar cells has been topical recently. The current study focuses on the effect of rare earth Tm doping on the charge transfer and magneto-optical properties of TiO₂. The Tm doping effect on TiO₂ shows a transition from ferromagnetic—antiferromagnetic—ferrimagnetic features. A steady band gap narrowing is observed with Tm doping of TiO₂, which suggests increased localized defect buildup within the electronic structure of TiO₂. The transition from electropositive to electronegative charge transfer features suggests Tm doping can act as a means of tuning the optoelectronic properties of TiO₂. Additionally, the asymmetric spin-up and down features of Tm 4f orbital states suggest it is an active agent in tuning the magneto-optical properties of TiO₂ for improved organic solar cell harvesting.