Yang et al. demonstrated that the Schottky OSC architecture can be implemented using solution-processed and polymer donor materials, such as poly(3-hexylthiophene) (P3HT), poly[4,8-bis-substituted-benzo[1,2-b:4,5-b′]dithiophene- 2,6-diyl-alt-4-substituted-thieno[3,4-b]thiophene-2,6-diyl] (PBDTTT-C-T), 5-(2,6-bis((E)-2-(3,4-dioctyl-[2,2′:5′,2′′:5′′,2′′′-quaterthiophen]-5-yl)vinyl)-4H-pyran-4-ylidene)-1,3-diethyl-2-thioxodihydropyrimidine-4,6 (1H, 5H)-dione (8TPDC8), and fluorine-substituted poly[2,3-bis-(3-octyloxyphenyl) quinoxaline- 5,8-diyl-alt-thiophene-2,5-diyl] (FTQ).36 They compared the performance of these materials in BHJ and Schottky OSCs. The concentration of donor material in the BHJ OSC was 50%, whereas the concentration of donor material in the Schottky OSC was 5%. Despite their varying HOMO and LUMO energy level offsets with , the of the cells with the different donor materials remained constant at 0.85 V–0.87 V in the Schottky OSCs. The was reflective of the energy level difference in BHJ OSCs. The efficiency of the Schottky OSC reached 3.3%, with similar levels of performance from FTQ and PBDTTT-C-T donors. However, 8TPDC8 was observed to have a very low FF and, consequently a lower efficiency. Yang et al. suggested that the donor material increases the dissociation efficiency of excitons with high binding energy in the fullerene material, whereas excitons with lower binding energy undergo field-assisted dissociation. This notion is discussed in further detail in Sec. 3 of this review.