Described herein is a photoreceptor and a method of making metal oxide particles having hygroscopic polymers attached to a surface of the metal oxide particles. The photoreceptor includes a conductive substrate and an undercoat layer disposed on the conductive substrate. The undercoat layer includes metal oxide particles having hygroscopic polymers attached to a surface of the metal oxide particles. The undercoat layer includes a binder resin. A photosensitive layer is disposed on the undercoat layer.