High-Performance Bulk-Heterojunction Polymer Solar Cells - Low-cost Nanomaterials: Toward Greener and More Efficient Energy Applications - page 168

Fig. 2 a Grazing-incidence XRD patterns of P3HT:PCBM thin films before and after thermal
annealing. b Graphical representation of the microscopic behavior in P3HT/PCBM blends during
thermal annealing [ 13 ]
Fig. 3 a XRD diagram of P3HT/PCBM blends before and after thermal annealing at 150 C for
30 min. Inset: P3HT crystalline structure. b AFM images of P3HT/PCBM blends annealed at
150 C for 30 min after the removal of the Al cathode: (top) annealed prior to Al deposition;
(bottom) annealed after Al deposition [ 14 ]
consisting of 1-chloronaphthalene (Cl-naph) and o-dichlorobenzene (DCB) [ 19 ].
Because the vapor pressure of Cl-naph is lower (0.029 mm Hg) than that of DCB
(1.2 mm Hg), the addition of Cl-naph decreases the volatility of the solvent for the
photoactive layer and extends the drying time of the polymer film. Therefore, the
polymers have a longer time during which to undergo self-organization, thereby
increasing the degree of crystallinity. Such approaches using solvent mixtures or