Upconversion nanoparticles (UCNPs) represent a class of optical nanomaterials that can convert low-energy excitation photons to high-energy fluorescence emissions. Despite great progress, spectral profiles of lanthanide-doped UCNPs are still limited by several intrinsic issues: weak absorption cross-sections, fixed emission wavelengths, low quantum yield, etc. In recent years, it has been witnessed great achievements in engineering spectral properties of UCNPs through many energy management approaches. Following the energy-cascade process in a typical upconverting scheme, this review will first summarize various energy management strategies, from energy harvesting to energy migration, and to luminescence output, with a focus on clarification of underlying mechanisms of spectral tuning based on these strategies. Then, a summary of emerging applications of UCNPs will be covered. Challenges and potential solutions in this field will also be discussed as a conclusion.

上转换纳米粒子 (UCNPs) 是一类可以将低能激发光子转换为高能荧光发射的光学纳米材料。尽管取得了很大进展，但镧系元素掺杂的 UCNPs 的光谱分布仍然受到几个固有问题的限制：吸收截面弱、发射波长固定、量子产率低等。 近年来，它在工程光谱特性方面取得了巨大成就。 UCNPs 通过许多能源管理方法。遵循典型上转换方案中的能量级联过程，本综述将首先总结各种能量管理策略，从能量收集到能量迁移，再到发光输出，重点是阐明基于这些策略的光谱调谐的潜在机制。然后，将涵盖 UCNP 新兴应用的摘要。该领域的挑战和潜在解决方案也将作为结论进行讨论。