Tuning photoresponse through size distribution control of silicon quantum dots

► We present a novel strategy to maximize the photoresponse through size distribution control of the Si quantum dots. ► We take advantage of the inherent size distribution to provide a marked improvement of light harvest for the potential application in quantum dot rainbow solar cells. ► We show that there is a tradeoff between the absorption enhancement and tunneling loss for the photocurrent intensity in Si quantum dots. ► We develop a new approach for maximizing light energy conversion with relative simple and low cost manufacturing process.