Two-photon absorption spectra of silicon quantum dots and simulations of efficiency for bio-imaging

What is it about?

We measured the spectra of two-photon absorption in two different sizes of nanocrystalline silicon quantum dots by calibrating two-photon excited photoluminescence to a known reference standard. Excitation of photoluminescence by two-photon absorption can be advantageous for bio-imaging due to the ability to use redder light with deeper penetration depth in biological tissue and increased depth contrast. We simulated the efficiency of two-photon excited photoluminescence for bio-imaging applications of silicon quantum dots and compared them to other imaging agents and found that they were comparable or superior. Another advantage of silicon quantum dots in bio-imaging applications is their nontoxicity.

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Photo by Daniel Lozano Valdés on Unsplash

Photo by Daniel Lozano Valdés on Unsplash

Why is it important?

We present the first absolute measurement of two-photon absorption cross section spectra in two different sizes of nanocrystalline silicon quantum dots over a wide range of wavelengths. We also simulate their efficiency for bio-imaging applications and compare to other imaging agents to aid developers in this field.