In this report, we introduced subwavelength sanding treatment to boost the cost-effectiveness of luminescent solar concentrators (LSCs). It was proven the hypothesis that sanding the device surface to roughness (R-q = 22-105-nm) much smaller than the wavelength of sunlight (lambda = 280-4000 nm) would improve the device performance due to much higher scattering gain than scattering loss. Experimental results showed that the sanded devices exhibited power conversion efficiency (eta(LSC)) and power concentration ratio (C) enhanced by at least 44% and could have the doping concentration of the luminophores significantly reduced by 87.5%. Measurement on the waveguide edge emission revealed that the performance enhancement was attributed to the utilization of the long-wavelength (lambda > 800 nm) photons. Monte Carlo ray tracing simulation signified that the subwavelength sanding treatment was also applicable to large-area devices with geometric gain (G) up to 120 (9.29 m(2)) and devices made of other luminophores. Cost-effectiveness analysis indicated a huge reduction by 45% in the price per watt (PPW) for large-area commercial-sized (80 in. by 40 in.) LSCs. This study suggested that subwavelength sanding treatment was promising to bridge the gap between research and commercialization of the LSCs.