Water photolysis is a sustainable technology to convert natural solar energy and water into chemical fuels and is thus considered a thorough solution to the forthcoming energy crises. Unassisted water splitting that could directly harvest solar light and subsequently split water in a single device has become an important research theme. Three types of tandem devices including photoelectrochemical (PEC), photovoltaic (PV) cell/PEC and PV/electrolyser tandem cells are proposed to realize water photolysis at different levels of integration and component. Recent progress in tandem water splitting devices is summarized, and crucial issues on device optimization from the perspective of each photo-absorber functionalities in band edge potential, light absorptivity and transmittance are discussed. By increasing the performances of stand-alone PEC or PV devices, a 20% solar to hydrogen efficiency is predicted that is a significant value towards further application in practice. Accordingly, the challenges for materials development and configuration optimization are further outlined.
Bibliographical noteFunding Information:
K.Z. and M.M. contributed equally to this work. This work was supported by the NRF of Korea Grant funded by the Ministry of Science, ICT & Future Planning (NRF-2013R1A2A1A09014038, 2015M1A2A2074663, 2014R1A1A1002419).
All Science Journal Classification (ASJC) codes
- Renewable Energy, Sustainability and the Environment
- Materials Science(all)