A day-night solar thermoelectric generator enabled by phase change material and forced water cooling

•A novel STEG is proposed with the combination of home-made solar selective absorber, transparent phase change materials of methyl palmitate and forced water cooling.•The temperature difference is dramatically increased and the duration of hot end temperature is substantially extended.•A new fabricated solar selective absorber exhibits a high solar absorption of 96.05 %, leading to its surface temperature up to 100 °C under 1-sun illumination (1 kW m−2).•The temperature difference of hot/cold end can significantly increase to 5.6 °C from 2 °C, about 2.8 times higher than conventional thermoelectric module.•An output voltage of 307.3 mV is demonstrated by this unconcentrated PCM-STEG-WC, which is about 9 times higher than that of conventional thermoelectric module (35.5 mV).