Research

Topic 1: Developing photoelectrodes using wide bandgap perovskites and organic semiconductor absorbers 

Halide perovskites which have in particular wide bandgap (>1.4 eV) can drive most of photoelectrochemical reactions in principle. Organic photovoltaic devices employing bulk heterojunctions (BHJs) of polymer donors and small molecular nonfullerene acceptors have recently demonstrated high performance, with strong visible and near-infrared absorption and low energy losses. Such junctions are promising candidates for solar-driven water splitting; however, the poor underwater stability in such devices has limited their viability to date. The LTH group SF team has a primary research interest in the improvement of stability and performance of our solution-processed photoelectrodes to upgrade the possibility toward solar-driven fuel production by PEC cells based on economical and scalable semiconductors.

Topic 2: Designing tandem architectures for water electrolysis 

Hetero-tandem devices consisting of wide- and small-bandgap materials provide high photovoltages and serve as an ideal light absorber to drive water electrolysis. The tandem PV is combined with an electrolyser to demonstrate a photovoltaic-electrolysis (PV-EC) system, which has most possibility to represent  a benchmark for PV-based solar fuel production. Furthermore, a wireless monolithic artificial leaf can be constructed, which has a potential to reduce the device complexity of PV-EC system. The LTH group PV and SF team has a further research interest in integrating them into photoelectrochemical devices.

Topic 3: Investigating carrier dynamics at semiconductor/electrolyte interfaces in photoelectrochemical devices 

Photogenerating charges with long lifetimes to drive catalysis is challenging in such semiconductors. Femtosecond transient absorption (TA) measurements show the yield of long-lived polarons from semiconductors. Furthermore, by operando photoinduced absorption (PIA) spectroscopic analyses, the successful PEC device is observed to extend the photogenerated charge lifetime to the seconds timescale, correlated with photocurrent generation. Our team investigates an effective design strategy for generating longer charge carrier lifetimes in photoelectrodes for efficient reduction/oxidation catalysis.