In room temperature photoluminesence, if the size of the particle increases, then how does it influence non-radiative recombinations? Are they suppressed?
Many effects should be considered in this question. If you assume the defect density in the bulk does not change, with increasing the size, the surface effect, typically causing "non-radiative recombination" to the band edge states, becomes less significant. The well-known examples are those nano-crystals and wires show very low emission efficiency, if their surface are not passivated. Of course, changing the size also changes the wavefunctions, thus impacts the relative efficiency between the radiative and non-radiative recombination.
With the increasing size of the nanoparticles increases the matrix element of the transition dipole moment (oscillator strength). This leads to an increase in energy of the dipole-dipole interaction between the nanoparticles and, consequently, to increase the probability of nonradiative recombination. Professor of Theoretical Physics
With increasing size of the particle the band gap decreases and I would expect that the non-radiative part of the relaxation would increase with increase of particle size.
Many effects should be considered in this question. If you assume the defect density in the bulk does not change, with increasing the size, the surface effect, typically causing "non-radiative recombination" to the band edge states, becomes less significant. The well-known examples are those nano-crystals and wires show very low emission efficiency, if their surface are not passivated. Of course, changing the size also changes the wavefunctions, thus impacts the relative efficiency between the radiative and non-radiative recombination.
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