Recent advancements in colloidal chemistry offer unique opportunities to construct core/shell semiconductor nanocrystals (NCs) with tailored optical properties. Major efforts have been focused on synthesizing core/shell NCs via heteroepitaxial growth, which often leads to effective surface passivation and thus reduced trap states (TS). However, the growth of a shell with a wider band gap or energy band offset tends to form a physical barrier for the migration of photo-generated charge carriers to the surrounding environment, resulting in compromised photoactivity. Here, we show that the homoepitaxial growth of NCs is able to facilitate the passivation of TS without affecting the migration of charge carriers to the surface of NCs. Homostructured CdS_homo NCs have demonstrated improved photocatalytic hydrogen production compared with the CdS core NCs and heterostructured CdS/ZnS core/shell NCs in terms of both efficiency and photostability. We envision that homoepitaxial growth would provide new opportunities to tailor semiconductor NCs for photocatalytic and photovoltaic applications.

中文翻译：

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在半导体纳米晶体上进行同质外延生长以有效且稳定地产生可见光光催化氢

胶体化学的最新进展为构建具有定制光学特性的核/壳半导体纳米晶体（NC）提供了独特的机会。主要的努力集中在通过异质外延生长合成核/壳NC上，这通常导致有效的表面钝化并因此降低陷阱态（TS）。然而，具有较宽的带隙或能带偏移的壳的生长趋向于形成用于光生电荷载流子向周围环境迁移的物理屏障，从而导致光活性受损。在这里，我们表明NCs的同质外延生长能够促进TS的钝化而不会影响电荷载流子向NCs表面的迁移。同质CdS_均质与CdS核心NC和异结构CdS / ZnS核心/壳型NC相比，NC在效率和光稳定性方面均表现出更高的光催化制氢能力。我们设想同质外延生长将为定制用于光催化和光伏应用的半导体NC提供新的机会。