of two different materials. [7,[16][17][18][19] It also enables the hybrids to inherit the superior mechanical flexibility of organic materials. [20,21] Since the first CQD/ organic hybrid solar cells were proposed, [22] efforts have been underway to improve the PCE. Although many previous studies successfully demonstrated complementary absorption, the PCEs of hybrid solar cells are still affected by inefficient charge extraction, caused by 1) the short exciton diffusion length in polymers, [19] 2) poor nanomorphology of the CQD:polymer mix causing unfavorable charge transfer pathways, and 3) local trap sites at the interfaces of CQD and polymer. [18] Various strategies such as exploration of new materials for use in the hybrids, [23][24][25][26][27] tuning CQD size, [18,28] molecular modification, [18,29] and ligand exchange [30,31] have been proposed to enhance the charge extraction in CQD/polymer hybrids. Among them, tuning the CQD surface using organic/inorganic ligands has been widely investigated because it can modify the CQD surface that affects the electrical properties. [16,32,33] Recently, a small-molecule bridge was employed in CQD/ organic hybrid solar cells to overcome the short exciton diffusion length problem; [34,35] however, the hybrid cells still suffer from substantial trap sites at the CQD/organic interfaces, limiting charge extraction. The CQD/organic interfaces have many trap sites due to the large difference in surface energy between the CQD and polymer, [18] the presence of insulating ligands, [16] and defects on the CQD surfaces. [36] These CQD/polymer interfaces potentially hinder charge transport and induce bimolecular recombination.In this work, we systematically investigated how the CQD/ organic interfaces influenced the charge transport properties. First, we replaced the native ligand of CQD with halides to form conventional CQD solids. [37] Subsequently, a polymer layer was stacked onto the CQD solid to form a CQD/organic heterointerface. Additionally, an auxiliary interfacial layer passivated by various organic ligands was implemented at the CQD/polymer interface. The interfacial layer that provides the cascading conduction band offset (ΔE C ) between CQD and polymer relieved band bending that adversely hinders the charge transfer at CQD/polymer interfaces. The reduced band bending facilitated the charge transfer across the heterojunction by suppressing charge accumulation -as confirmed by transient photocurrent (TPC) spectroscopy -and by reducing bimolecular recombination at the CQD/polymer interfaces.Emerging semiconducting materials including colloidal quantum dots (CQDs) and organic molecules have unique photovoltaic properties, and their hybridization can result in synergistic effects for high performance. For realizing the full potential of CQD/organic hybrid devices, controlling interfacial properties between the CQD and organic matter is crucial. Here, the electronic band between the CQD and the polymer layers is carefully modulated by inserting an interfacial layer treated...