Superconformally filling a recessed feature includes: contacting the recessed feature with superconformal filling composition that includes: Au(SO3)23− anions; SO32− anions; and Bi3+ cations; convectively transporting Au(SO3)23− and Bi3+ to the bottom member of the recessed feature; subjecting the recessed feature to an electrical current to superconformally deposit gold from the Au(SO3)23− on the bottom member relative to the sidewall and the field, the electrical current providing a cathodic voltage; and increasing the electrical current subjected to the field and the recessed feature to maintain the cathodic voltage between −0.85 V and −1.00 V relative to the SSE during superconformally depositing gold on the substrate to superconformally fill the recessed feature of the article with gold as a superconformal filling of gold, the superconformal filling being void-free and seam-free.