<p>Detection performance of filter-free fluorescence sensors in the near-ultraviolet region has improved in this study. Thinner polycrystalline-Si film and indium tin oxide film were introduced as materials of photogate which required high transparency for sensitive measurement. Optical property of the photogate material was evaluated. Filter-free fluorescence sensors which have photogates with high optical transmittance were fabricated based on standard CMOS process. As results of a demonstration which emulates separate detection of excitation light and fluorescence by the fabricated filter-free sensors, detection performance in the near-ultraviolet region has improved a hundredfold compared to a previous sensor.</p>