TABLE 5.

Use of physical characterization techniques

Technique	n (of 51)	References
Optical/Electrical Methods (OEM): RPS, NTA, DLS	22	44‐49,52,54,55,57,60,63,66,70,72,75‐77,80,85,87,88
Non‐Optical Microscopy (NOM): TEM, SEM, AFM	19	28,35,46,49,52‐55,57,58,62,64,75,76,79,82,84,85,90
Multiple	10	46,49,52,54,55,57,75‐77,85,90
None (in several cases, techniques were mentioned but results not reported)	19	36,39,50,51,56,59,61,65,67‐69,71,73,74,78,81,83,86,89