All-Perovskite Tandem Photoelectrodes for Unassisted Solar Hydrogen Production
Zhaoning Song, Chongwen Li, Lei Chen, Kshitiz Dolia, Sheng Fu, Nannan Sun, You Li, Keenan Wyatt, James L. Young, Todd G. Deutsch, Yanfa Yan
Abstract
Unassisted solar water splitting by multijunction tandem photoelectrodes is a sustainable approach to generating green hydrogen fuels. Here, we report on the fabrication of monolithically integrated all-perovskite tandem photocathodes for efficient unassisted solar water splitting. All-perovskite tandem photocathodes wired to an iridium oxide anode deliver a high photovoltage of more than 2 V with an operating photocurrent density of 12.5 mA cm –2 at zero applied bias under simulated AM1.5G 1 sun illumination, yielding a solar-to-hydrogen (STH) conversion efficiency of 15%. The tandem photoelectrode demonstrates continuous operation in water for more than 120 h under simulated 1 sun illumination with less than 5% efficiency loss. A technoeconomic analysis shows the projected production cost of all-perovskite tandem photoelectrodes is $30 m –2, promising a levelized cost of hydrogen of less than $1/kg if sufficient device longevity is realized. This work provides a path toward achieving cost-effective unassisted solar hydrogen fuel production.