A hybrid tandem solar cell consisting of a thin-film, nanocrystalline silicon top junction and a silicon heterojunction bottom junction is proposed as a supporting solar cell for photoelectrochemical applications. Tunneling recombination junction engineering is shown to be an important consideration in designing this type of solar cell. The best hybrid cell produced has a spectral utilization of 30.6 mA cm(-2) a J(sc) of 14 mA cm(-2), a V-oc of 1.1 V, a fill factor of 0.67 and thus an efficiency of 103%. A high solar-to-hydrogen efficiency of 7.9% can be predicted when using the hybrid cell in conjunction with current a-SiC photocathode technology. (C) 2016 Elsevier B.V. All rights reserved.