Solution‐processed hybrid solar cells employing a low band‐gap polymer and PbSxSe1‐x alloy nanocrystals, achieving a record high PCE of 5.50% and an optimal FF of 67% are presented. The remarkable device efficiency can be attributed to the high‐performance active materials, the optimal polymer/NCs ratio and, more importantly, the vertical donor/(donor:acceptor)/acceptor structure which benefits charge dissociation and transport.