Due to barrierless free charge generation, low charge trapping, and high charge mobilities, the PM6:Y6 organic solar cell (OSC) achieves an excellent power conversion efficiency (PCE) of 15.7%. However, the deficient hole transfer from Y6 to PM6 limits the further enhancement of the device performance. Herein, we demonstrate an additive-induced miscibility and morphology control strategy to achieve the balance of exciton dissociation and charge collection, prompting an increase in the PCE of OSCs composed of PM6:Y6 from 15.7% to 17.5%, which stands as the top PCE value of PM6:Y6 binary OSCs. The external quantum efficiency (EQE) of the optimal device significantly improves in the wavelength range where Y6 harvests photons. Therefore, the short-circuit current density (J_SC) was enhanced to 26.98 mA cm⁻², achieving 94.4% of the maximum theoretical J_SC obtained from the identical device configuration. The remarkable performance enhancement mainly results from the miscibility-driven donor and acceptor phase optimization with hierarchical morphology formation, leading to the improved photon-to-electron response of the Y6 phase, enhanced and balanced charge extraction and collection. Our findings highlight the significance of morphology control towards unleashing the full potential of OSC materials.

Recent research efforts on solution‐processed semitransparent organic solar cells (OSCs) are presented. Essential properties of organic donor:acceptor bulk heterojunction blends and electrode materials, required for the combination of simultaneous high power conversion efficiency (PCE) and average visible transmittance of photovoltaic devices, are presented from the materials science and device engineering points of view. Aspects of optical perception, charge generation–recombination, and extraction processes relevant for semitransparent OSCs are also discussed in detail. Furthermore, the theoretical limits of PCE for fully transparent OSCs, compared to the performance of the best reported semitransparent OSCs, and options for further optimization are discussed.