I understand this may be an unusual and maybe not even a feasible approach. In comparison to a cluster of small quantum dots, around 5nm is bound by a conic dna structure, versus a larger quantum dot of the same size comparatively to a cluster of quantum dots. I am interested in using DNA origami to cluster small quantum dots to increase the emission intensity.
I have attached a publication regarding DNA origami used to attach quantum dots.
Also I am aware that larger quantum dots will have emission spectrums of increased wavelengths.
Thank you!
Article Hierarchical assembly of metal nanoparticles, quantum dots a...
While clustering of small nanoparticles should in theory increase the emission intensity, at least in the sense that the local concentration of emitters will be higher, it may not be quite this simple. For one thing, are you planning on using core or core-shell Quantum Dots? I ask as clustering of particles may result in quenching of particles if they are too close due to electron transfer between adjacent particles, especially if you are using core particles. At the very least the interparticle separation may prove important.
Another consideration, depending on what environment the particles will be in, is that a small cluster of particles that have the same 'footprint' on a 2D substrate will have a lower volume and a greater surface area. While the lower volume may not be critical, the higher surface area means they will be more easily quenched by surface effects.
Lastly, if you are simply interested in having high intensity green emission, it might be better to use one of the recent approaches to particle synthesis that employ either 'giant shells' of CdS on a CdSe core, or alloying of CdSe/CdS/ZnS.
http://www.nature.com/nmat/journal/v12/n5/full/nmat3539.html?WT.ec_id=NMAT-201305
http://pubs.acs.org/doi/abs/10.1021/cm402645r