Beschreibung:
<jats:p>A theoretical model of fluctuations of the number of adsorbed
micro/nanoparticles in environmental sensors operating in air and liquids is
presented, taking into account the effects of the mass transfer processes of
the target particles in a sensor reaction chamber. The expressions for the
total power of the corresponding adsorption-desorption noise, and for the
corresponding signal-to-noise ratio are also derived. The presented analysis
shows that the transfer processes can have a significant influence on the
sensors limiting performance. The influence on both the fluctuations
spectrum and the signal-to-noise ratio is estimated at different values of
target particles concentration, functionalization sites surface density, and
adsorption and desorption rate constants (the values are chosen from the
ranges corresponding to real conditions). The analysis provides the
guidelines for optimization of sensor design and operating conditions for
the given target substance and sensor functionalization, in order to
decrease the influence of the mass transfer, thus improving the ultimate
performance (e.g. minimal detectable signal, signal-to-noise ratio) of
sensors for particle detection. The calculations we performed show that it
is possible to increase the signal-to-noise ratio for as much as two orders
of magnitude by using the optimization that eliminates the mass transfer
influence.</jats:p>