Environmentally friendly InP/ZnSe core/shell quantum dots (QDs) with high absorption coefficients and tunable band gaps have demonstrated great potential for photoelectrochemical (PEC) water splitting. However, the tightly bound excitonic feature by inherent type I band alignment tends to reduce the charge separation efficiency, limiting their PEC performance. Herein, we devised heterovalent In³⁺ gradient doping in the ZnSe shell of InP QD to construct core/shell structural InP/ZnSe-G-In QDs. The In³⁺ dopant increased the Fermi level of the ZnSe shell; thus continuous semiconductor homojunction and band bending were formed by gradient composition doping, which accelerates the exciton separation through the built-in electric field. As a result, the PEC cells based on such QDs exhibited high photocurrent density of 8.7 mA/cm², demonstrating one of the highest values for the InP-based QDs PEC cells. This work provides an effective strategy for the application of type I band structure QDs in solar energy conversion.

中文翻译：

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构建用于光电化学电池的壳梯度 In3+ 掺杂的 InP/ZnSe 量子点

具有高吸收系数和可调带隙的环保型InP/ZnSe核/壳量子点（QD）在光电化学（PEC）水分解方面表现出巨大的潜力。然而，固有的 I 型能带排列带来的紧密束缚激子特征往往会降低电荷分离效率，从而限制其 PEC 性能。在此，我们设计了在InP QD的ZnSe壳层中进行异价In ³⁺梯度掺杂，以构建核/壳结构的InP/ZnSe-G-In QDs。 In ³⁺掺杂增加了ZnSe壳层的费米能级；通过梯度成分掺杂形成连续的半导体同质结和能带弯曲，通过内建电场加速激子分离。结果，基于此类QD的PEC电池表现出8.7 mA/cm ²的高光电流密度，这是基于InP的QD PEC电池的最高值之​​一。该工作为I型能带结构量子点在太阳能转换中的应用提供了有效的策略。