A transparent p-type semiconductor designed <i>via</i> a polarizability-enhanced strongly correlated insulator oxide matrix

Abstract

Electron-transporting transparent conducting oxides (TCOs) are a commercial reality, however, hole-transporting counterparts are far more challenging because of limited material design. Here, we propose a strategy for enhancing the hole conductivity without deteriorating the band gap (E-g) and workfunction (Phi) by Cu incorporation in a strongly correlated NiWO4 insulator. The optimal Cu-doped NiWO4 (Cu0.185Ni0.815WO4) exhibits a resistivity reduction of similar to 10(9) times versus NiWO4 as well as band-like charge transport with the hole mobility approaching 7 cm(2) V-1 s(-1) at 200 K, a deep Phi of 5.77 eV, and E-g of 2.8 eV. Experimental and theoretical data reveal that the strength of the electron correlation in NiWO4 is unaffected by Cu incorporation, while the promoted polarizability weakens electron-phonon coupling, promoting the formation of large polarons. Quantum dot light-emitting and oxide p/n junction devices incorporating Cu0.185Ni0.815WO4 exhibit remarkable performances, demonstrating that our approach can be deployed to discover new p-type TCOs.