Converting solar energy to chemical energy in the form of hydrogen via water splitting is one of the promising strategies to solve the global energy crisis. Hematite, a traditional semiconducting oxide photoelectrode, can only absorb UV and visible parts of the solar spectrum, losing 40% infrared energy. In this paper, we report a novel plasmonic enhanced water splitting photoanode based on hematite-lanthanide upconversion nanocomposites to harvest lost photons below the bandgap of hematite. NaYF₄:Er, Yb upconversion nanoparticles can upconvert photons from 980 nm to 510 nm–570 nm within the bandgap of hematite. More importantly, a gold nanodisk array with a plasmonic peak centered ∼1000 nm can further boost the photocurrent by 93-fold. It is demonstrated that the excitation process of lanthanide upconversion nanoparticles can be significantly enhanced by plasmonic nanostructures and can thus improve the water oxidation activity via plasmonic enhanced upconversion and hot electron injection, respectively. This new promising strategy will pave the way for plasmonic enhanced lost photon harvesting for applications in solar energy conversion.

中文翻译：

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通过等离子体增强的赤铁矿-上转换纳米复合材料收集丢失的光子，用于水分解。

通过水分解将太阳能以氢的形式转化为化学能是解决全球能源危机的有前途的战略之一。赤铁矿是传统的半导体氧化物光电极，只能吸收紫外线和太阳光谱中的可见部分，损失40％的红外能量。在本文中，我们报道了一种基于赤铁矿-镧系元素上转换纳米复合材料的新型等离激元增强水分解光阳极，以收集在赤铁矿带隙以下的损失光子。NaYF ₄：Er，Yb上转换纳米粒子可以在赤铁矿的带隙内将光子从980 nm上转换为510 nm至570 nm。更重要的是，等离子峰中心在〜1000 nm处的金纳米盘阵列可以将光电流进一步提高93倍。结果表明，镧系元素上转换纳米粒子的激发过程可以通过等离激元纳米结构得到显着增强，从而可以分别通过等离激元增强上转换和热电子注入提高水的氧化活性。这一新的有前途的策略将为等离子增强的丢失光子的收集铺平道路，以用于太阳能转换。