BiVO<sub>4</sub> Polaron-Hopping State-Induced Low-Bias\nSpintronic Water Splitting Device

Both n-type and p-type BiVO<sub>4</sub> photoelectrodes\ndemonstrate\na high performance in water splitting devices, with an ultrahigh solar\nto hydrogen energy conversion performance as high as 6.77 and 7.51%,\nrespectively. The external quantum efficiencies of the n-type and\np-type BiVO<sub>4</sub> photoelectrodes under 520 nm laser irradiation\nare 54.52 and 48.38%, respectively. Besides, over 49 L of hydrogen\ngases evolved from the n-type BiVO<sub>4</sub> photoelectrode and\nover 32 L of hydrogen gases from the p-type BiVO<sub>4</sub> photoelectrode.\nWith the polaron surface state and the polaron-hopping energy level,\nthe p-type BiVO<sub>4</sub> demonstrated over 50% spin polarization\nrate since ℏ/–ℏ angular momentum-modulated circular\npolarization serves as the spintronic excitation light source. The\nhole-trapping Fermi level of the p-type BiVO<sub>4</sub> affords the\nwater splitting devices a shorter path for hole transportation than\nthe n-type BiVO<sub>4</sub>.