Plasmonics and magnetism from doped colloidal indium oxide nanocrystals

Abstract

Transparent conducting oxides TCOs are metal oxides capable of exhibiting mutually exclusive properties of high electrical conductivity and transparency to the visible light Through lattice doping one can either enhance the electrical conductivity of TCOs which enables their application to different optoelectronic applications or introduce new functionalities in them On the other hand decreasing the size of TCOs to nano regime allows them to exhibit localized surface plasmon resonance LSPR in the near infrared NIR region In this work we combine the control of size and doping on the properties of a material to yield codoped TCO nanocrystals NCs Using In2O3 as the host TCO we incorporated two dopants Sn4 and a transition metal T M colloidally to synthesize the codoped In2O3 NCs While Sn4 doping provides electrical conductivity and LSPR T M doping is expected to introduce localized magnetic spins giving rise to magnetism Results show that interactions can indeed be observed between the two dopants in the NC Through these interactions we achieve a tunable LSPR electrical conductivity and magnetism from Fe Sn codoped In2O3 NCs By changing the T M dopant to Mn2 we were able to achieve nearly ideal magnetic moment of 5 956 B Mn2 ion in Mn Sn codoped In2O3 NCs On the other hand we find that Cr Sn codoped In2O3 NCs exhibit one of the highest figure of merit Q factors for LSPR We used the fundamental understanding to develop a strategy for designing doped TCOs with high LSPR Q factors and employed them to synthesize Zr doped In2O3 NCs which exhibit high LSPR Q factors in the mid infrared region In the last chapter using Cr Sn codoped In2O3 NCs we elucidated the primary factors that govern modulation of NIR LSPR under an applied external potential newline newline