Semiconductor colloidal quantum dots (CQDs) offer size- and composition-tunable luminescence of high colour purity. Importantly, their emission can be tuned deep into the second biological near-infrared (NIR-II) window (1,000–1,700 nm). However, applications are hindered by the low efficiencies achieved to date. Here, we report NIR-II CQD light-emitting diodes with an external quantum efficiency of 16.98% and a power conversion efficiency of 11.28% at wavelength 1,397 nm. This performance arises from device engineering that delivers a high photoluminescence quantum yield and charge balance close to unity. More specifically, we employed a binary emissive layer consisting of silica-encapsulated silver sulfide (Ag₂S@SiO₂) CQDs dispersed in a caesium-containing triple cation perovskite matrix that serves as an additional passivation medium and a carrier supplier to the emitting CQDs. The hole-injection contact also features a thin porphyrin interlayer to balance the device current and enhance carrier radiative recombination.

半导体胶体量子点（CQD）可提供尺寸和组成可调的高色纯度发光。重要的是，它们的发射可以深入到第二个生物近红外（NIR-II）窗口（1,000-1,700 nm）中。但是，迄今为止的低效率阻碍了应用。在这里，我们报告了在波长1,397 nm处具有16.98％的外部量子效率和11.28％的功率转换效率的NIR-II CQD发光二极管。此性能源于设备工程学，该技术可提供高的光致发光量子产率和接近于1的电荷平衡。更具体地说，我们采用了由二氧化硅包裹的硫化银（Ag ₂ S @ SiO ₂）CQD分散在含铯的三阳离子钙钛矿基质中，该基质用作额外的钝化介质和发光CQD的载体供应商。空穴注入触点还具有一个薄的卟啉夹层，以平衡器件电流并增强载流子的辐射复合。