Poly vinyl phenol

N-type organic semiconductor polymer, poly{[N,N′-bis(2-octyldodecyl)naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5′-(2,2′-bithiophene)} (N2200, LUMO: −3.8 eV, M_w = 289,730, M_n = 150,497), was purchased from Ossila (Sheffield, England) and used without purification [21 (link)]. The N2200 was dissolved in o-dichlorobenzene at 0.2 wt%. The organic semiconductor ink was filtered with a 0.44 µm hydrophobic filter after being stirred at 70 °C for 1 day. Cross-linked poly(vinyl phenol) (C-PVP) was prepared by dissolving 10 wt% each of poly(vinyl phenol) (M_w = 25,000, Sigma-Aldrich, St. Louis, MO, USA) and poly(melamine-co-formaldehyde) methylated (M_n = 432, 84 wt% in 1-butanol, Sigma-Aldrich) in propylene glycol monomethyl ether acetate (PGMEA).