•First demonstration of solid-state Pb5Sb8S17 quantum dot-sensitized solar cells.•The best cell achieved a respectable efficiency of 4.14% and a normalized Jsc of 20.0 mA cm−2 under 10% sun.•The best efficiency is 65% higher than the best previous result.•Pb5Sb8S17 has a large optical absorption coefficient and a near optimal Eg.•External quantum efficiency (EQE) spectral range: 300–800 nm; maximal EQE = 65% at λ = 450 nm.