Colloidal semiconductor quantum dots (QDs) are promising materials for realizing high-performance liquid-junction photovoltaic cells. Solar cells based on Zn:CuInSe₂ QDs show high efficiency despite a large abundance of native defects typical of ternary I–III–VI₂ semiconductors. To elucidate the reasons underlying the remarkable defect tolerance of these devices, we conduct side-by-side photovoltaic and spectroscopic studies of as-prepared and surface-modified Zn:CuInSe₂ QDs. Using surface ligands with different lengths and binding affinities to the TiO₂ surface, we tune the rates of both defect-related relaxation and QD-to-TiO₂ electrode electron transfer. Despite their profound influence on photoluminescence dynamics, surface modifications have surprisingly little effect on photovoltaic performance suggesting that intragap defects do not impede but actually assist the photoconversion process in Zn:CuInSe₂ QDs. These intragap states, identified as shallow surface-located electron traps and native Cu¹⁺ hole-trapping defects, mediate QD interactions with the TiO₂ electrode and the electrolyte, respectively, and help achieve consistent photovoltaic performance with ~85% photon-to-electron conversion efficiencies and highly reproducible power conversion efficiencies of 9–10%.

胶体半导体量子点（QD）是用于实现高性能液结光伏电池的有前途的材料。尽管存在大量的I–III–VI ₂三元半导体典型的天然缺陷，但基于Zn：CuInSe ₂ QD的太阳能电池仍显示出高效率。为了阐明这些设备显着的缺陷耐受性的原因，我们对制备的和表面改性的Zn：CuInSe ₂ QD进行了并排光伏和光谱研究。使用具有不同长度和与TiO ₂表面的结合亲和力的表面配体，我们调整了缺陷相关弛豫和QD-to-TiO ₂的速率电极电子转移。尽管表面修饰对光致发光动力学有深远影响，但其对光伏性能的影响却出乎意料地几乎没有，这表明间隙内缺陷不会阻碍但实际上有助于Zn：CuInSe ₂ QDs的光转换过程。这些能隙状态被识别为浅层表面电子陷阱和天然Cu ¹⁺空穴俘获缺陷，分别介导了与TiO ₂电极和电解质的QD相互作用，并以约85％的光子对光子效应帮助实现了稳定的光伏性能。电子转换效率和9-10％的高可重复功率转换效率。