In the last 10 years, there has been extensive research by the nanoscience and catalysis communities on the potential use of plasmonic nanoparticles for both solar-to-electrical energy and solar-to-chemical fuel conversions. Herein, we present a critical review of the quickly expanding field of plasmon resonance-enhanced light energy harvesting. A wide range of enhancement phenomena have been observed: from enhanced light trapping in silicon solar cells loaded with plasmonic nanoparticles to plasmonically assisted hot carrier generation for photoelectrolysis, all of which are discussed in this review. We examine seminal findings, present various physical mechanisms potentially responsible for plasmonic enhancement, and also clear up some common fallacies about such enhancement phenomena. In addition, the review covers wide-open research opportunities for furthering deeper mechanistic understanding of plasmonic effects, engineering hybrid nanosystems optimized for efficient light-to-energy conversion, and translating promising effects to technologically relevant objectives. Plasmonically assisted solar energy conversion is a field rife with questions and opportunities for chemists and materials engineers alike. (C) 2015 Elsevier Ltd. All rights reserved.