Biopower generation in a microfluidic bio-solar panel

•We report a biosolar panel by installing miniature biosolar cells in an array format.•The connection of the nine cells in series generated 5.59μW maximum power.•The biosolar panel continuously generated electricity from bacterial activities. We developed a scalable and stackable bio-solar panel that integrated significantly improved miniature bio-solar cells in an array. A 3×3 bio-solar panel was fabricated by installing nine bio-solar cells with a common microfluidic channel. The bio-solar panel continuously generated electricity from cyanobacterial photosynthetic and respiratory activities under day–night cycles. The open circuit voltages from individual bio-solar cells differed by less than 2% to the cell units in the array. The connection of the nine cells in series generated 5.59μW maximum power and 1.28V operating voltage under a 200kΩ external resistor, which is the highest-reported numbers of any existing small-scale bio-solar cells. Bio-solar cell performance has improved significantly through miniaturizing innovative device architectures and connecting multiple miniature cells in a panel.