Non-conjugated organosilicone fluorescent nanoparticles for latent fingerprint detection

Highlights: • Si-NPs without typical fluorophores are applied for latent fingerprint imaging. • Si-NPs particles have blue fluorescence with quantum yield being 70.6%. • Si-NPs exhibit excellent stability in ultraviolet irradiation and wide pH range. • Improved stability is attributed to the protection of the silica matrix. • Clear fluorescent images on various substrates with high resolution are obtained. -- Abstract: In this paper, non-conjugated organosilicone fluorescent nanoparticles (Si-NPs) were synthesized by the Stöber method. The Si-NPs have a diameter of approximately 30 nm, uniform particle size, and a quantum yield of up to 70.6% ultra-bright blue light emission. The prepared non-conjugated siloxane fluorescent small molecule is covalently bonded to the silica matrix. The Si-NPs exhibited excellent stability in ultraviolet irradiation and a wide pH range, and their improved stable optical properties are attributable to the protection of the silica matrix. In addition, the effectiveness of Si-NPs for potential fingerprint detection on a variety of substrates is demonstrated. Clear optical/fluorescent images of the ridges and spaces with high contrast and resolution are obtained because the particle size of the obtained Si-NPs is much smaller than the width of the fingerprint ridges.