3 years, NFA-based OSC performance has improved remarkably, with several studies reporting efficiencies over 13% driven primarily through improved molecular design. [4][5][6][7] Particular progress has been made in enhancing the open circuit voltage (V OC ) of OSCs, achieved by use of NFAs with higher the lowest unoccupied molecular orbital (LUMO) levels as well as suppression of nonradiative recombination losses. [8][9][10][11][12][13][14] However, progress in achieving improvements in photocurrent generation has proven more challenging, despite NFAs typically exhibiting superior light-harvesting properties compared to fullerene acceptors. [15][16][17][18] Indeed, with a small number of notable exceptions, [19,20] most OSCs employing NFAs have yielded lower external quantum efficiencies (EQEs) than equivalent fullerene-based devices. In this paper, we undertake a meta-analysis of the device performance and transient spectroscopic results for various polymer:NFA and polymer:fullerene blends, employing three different electron donor polymers and seven different electron acceptors. From this analysis, we identify the primary factor limiting the efficiency of photocurrent generation in these blends and discuss its implications on materials design to further improve polymer:NFA blend solar cell performance.Following literature reviews, [21][22][23] the key processes of photocurrent generation in OSCs are illustrated in Figure 1a: exciton generation by light absorption, exciton diffusion to,