Laser-scribed wood photoabsorbers for sustainable interfacial solar steam and electricity co-generation

• Wood-based generator enables solar evaporation and hydrovoltaic production. • Photothermal graphite-Co 3 O 4 composite layer fabricated via a laser-engraving strategy. • Evaporation rate of 1.71 kg m -2 h −1 with 92.8 % efficiency under 1 sun irradiation. • V oc of ∼336 mV and I sc of ∼30 μA in pure water without sun irradiation. Interfacial solar steam generation has emerged as a promising approach for alleviating global freshwater shortages. Growing research interest focuses on harnessing sustainable biomass materials like wood to achieve dual-functional systems that produce freshwater while harvesting evaporation-induced energy for electricity generation. In this study, a laser-scribed wood photoabsorber is proposed to enable efficient co-generation of fresh water and electricity. Through brush-coating of cobalt nitrate solution followed by laser direct writing, a composite layer of graphite-Co 3 O 4 nanoparticles was successfully fabricated on the surface of basswood. Both cobalt salt coating and delignification processing were demonstrated to enhance the evaporation and electricity output performance of laser-engineered wood photoabsorbers. The device realized an evaporation rate and an efficiency of 1.71 kg m -2 h −1 and 92.8 % under 1 sun irradiation, respectively. Under ambient conditions without light irradiation, a single device (2 × 2 × 1 cm 3 ) was able to produce an open-circuit voltage of ∼336 mV and a stable short-circuit current of ∼30 μA in pure water. Furthermore, when multiple devices were connected in series, the generated voltage was sufficient to light a light-emitting diode or power an electronic calculator. Through laser-scribing of biomass materials, this study develops a sustainable solar interfacial evaporator capable of simultaneous freshwater production and electricity generation.