Colloidal quantum dots (CQDs) are of interest for optoelectronic applications owing to their tunable properties and ease of processing. Large‐diameter CQDs offer optical response in the infrared (IR), beyond the bandgap of c‐Si and perovskites. The absorption coefficient of IR CQDs (≈104 cm?1) entails the need for micrometer‐thick films to maximize the absorption of IR light. This exceeds the thickness compatible with the efficient extraction of photogenerated carriers, a fact that limits device performance. Here, CQD bulk heterojunction solids are demonstrated that, with extended carrier transport length, enable efficient IR light harvesting. An in‐solution doping strategy for large‐diameter CQDs is devised that addresses the complex interplay between (100) facets and doping agents, enabling to control CQD doping, energetic configuration, and size homogeneity. The hetero‐offset between n‐type CQDs and p‐type CQDs is manipulated to drive the transfer of electrons and holes into distinct carrier extraction pathways. This enables to form active layers exceeding thicknesses of 700?nm without compromising open‐circuit voltage and fill factor. As a result, 90% charge extraction efficiency across the ultraviolet to IR range (350–1400?nm) is documented.
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机译：由于其可调谐性能和易于加工，胶体量子点（CQDS）对光电应用感兴趣。大直径CQDS在红外（IR）中提供光学响应，超出C-Si和Perovskites的带隙。 IR CQDS（≈104cm≤1）的吸收系数需要需要微米厚的薄膜以最大化IR光的吸收。这超过了与光生载流子的有效提取兼容的厚度，这是限制装置性能的事实。这里，证明CQD散装异质结固体具有扩展载波传输长度，实现高效的IR光收获。设计了用于大直径CQDS的型掺杂策略，用于解决（100）刻面和掺杂剂之间的复杂相互作用，使控制CQD掺杂，能量配置和尺寸同质性。操纵N型CQD和P型CQD之间的杂偏移以驱动电子和孔的传送到不同的载流子提取途径。这使得能够在不影响开路电压和填充因子的情况下形成超过700ΩNM的厚度的有源层。结果，记录了紫外线的90％充电提取效率（350-1400？nm）。
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