• The introduction of hydroiodic acid (HI) manipulates the dynamic conversion of PbI₂ into highly coordinated species to optimize the nucleation and growth kinetics.

• The addition of HI enables the fabrication of CsPbI₃ perovskite quantum dots with reduced defect density, enhanced crystallinity, higher phase purity, and near-unity photoluminescence quantum yield.

• The efficiency of CsPbI₃ perovskite quantum dot solar cells was enhanced from 14.07% to 15.72% together with enhanced storage stability.

All-inorganic CsPbI₃ quantum dots (QDs) have demonstrated promising potential in photovoltaic (PV) applications. However, these colloidal perovskites are vulnerable to the deterioration of surface trap states, leading to a degradation in efficiency and stability. To address these issues, a facile yet effective strategy of introducing hydroiodic acid (HI) into the synthesis procedure is established to achieve high-quality QDs and devices. Through an in-depth experimental analysis, the introduction of HI was found to convert PbI₂ into highly coordinated [PbI_m]^2−m, enabling control of the nucleation numbers and growth kinetics. Combined optical and structural investigations illustrate that such a synthesis technique is beneficial for achieving enhanced crystallinity and a reduced density of crystallographic defects. Finally, the effect of HI is further reflected on the PV performance. The optimal device demonstrated a significantly improved power conversion efficiency of 15.72% along with enhanced storage stability. This technique illuminates a novel and simple methodology to regulate the formed species during synthesis, shedding light on further understanding solar cell performance, and aiding the design of future novel synthesis protocols for high-performance optoelectronic devices.

• 氢碘酸 (HI) 的引入可控制 PbI ₂动态转化为高度配位的物质，以优化成核和生长动力学。

• HI的添加使得能够制造具有降低的缺陷密度、增强的结晶度、更高的相纯度和接近一致的光致发光量子产率的CsPbI _{3钙钛矿量子点。}

• _{CsPbI 3}钙钛矿量子点太阳能电池的效率从14.07%提高到15.72%，同时存储稳定性也增强。

全无机 CsPbI ₃量子点 (QD) 在光伏 (PV) 应用中表现出巨大的潜力。然而，这些胶体钙钛矿很容易受到表面陷阱态恶化的影响，导致效率和稳定性下降。为了解决这些问题，我们建立了一种简单而有效的策略，将氢碘酸（HI）引入合成过程中，以实现高质量的量子点和器件。通过深入的实验分析，发现HI的引入将PbI ₂转化为高度配位的[PbI _m ] ^2−m，从而能够控制成核数量和生长动力学。结合光学和结构研究表明，这种合成技术有利于实现增强的结晶度和降低的晶体缺陷密度。最后，HI的影响进一步体现在PV性能上。最佳器件的功率转换效率显着提高，达到 15.72%，同时存储稳定性也增强。该技术阐明了一种新颖而简单的方法来调节合成过程中形成的物质，有助于进一步了解太阳能电池的性能，并有助于设计未来高性能光电器件的新型合成方案。