Figure 4: Detecting polymer aggregation with time.
From: A real-time study of the benefits of co-solvents in polymer solar cell processing

(a) Evolution of the absorption spectrum during spin coating of a PDPP5T:[70]PCBM film from chloroform with 3 vol% oDCB. (b) Laser interference (thin lines) and transmission of 780–820 nm light (thick semi-transparent lines) of PDPP5T:[70]PCBM films during spin coating from chloroform with different concentrations oDCB.