Nanoparticle Enhanced Ionic Liquids (NEILs) are the new heat transfer fluids for direct absorption solar collectors and are comprised of small vol/wt percentage of nanoparticles in base ionic liquids (ILs). In the present paper, NEILs are synthesized by dispersing Al₂O₃ nanoparticles in 1-butyl-3-methylimidazolium bis{(trifluoromethyl)sulfonylimide ([C₄mim][NTf₂]) ILs. The radiative properties of NEILs are investigated with different sizes and shapes (one rod-shaped type sized 10 × 100nm and four spherical sizes of 10 nm, 30 nm, 60 nm, and 90 nm) of Al₂O₃ nanoparticles. Five different concentrations (0.02%, 0.04%, 0.06%, 0.08%, and 0.1% wt) of NEILs were synthesized to investigate the concentration effect on radiative properties. The addition of Al₂O₃ nanoparticles greatly increased the light absorption capabilities of the ionic liquid [C₄mim][NTf₂], with at least a 26% decrease in transmittance observed with only 0.02% wt of nanoparticles. Differences in UV–vis absorption were more apparent in smaller concentrations; as much as 20% difference between nanoparticle types and larger concentrations varied in transmittance by as little as 5% between nanoparticle types. Nanofluids made of rod-shaped nanoparticles typically generated higher percentage transmittance values in 0.02%, 0.04%, and 0.06% wt of nanoparticles and were therefore less able to absorb light. Nanofluids made of 10 nm spherical nanoparticles yielded smaller percentage transmittance values at higher concentrations, as little as 2.7% transmission at 0.1% wt, and were therefore better able to absorb light. After completing the nanoparticle size and shape studies, three more NEILs were created from the ideal nanoparticle size and concentration in [C₂mim][NTf₂], [C₆mim][NTf₂], and [C₁₀mim][NTf₂] ILs. This investigation revealed an increase in percentage transmittance with increasing carbon chain length. [C₂mim][NTf₂] was determined to be the best-absorbing NEILs transmitting as little as 2.2% of light. Plausible reasons for the experimental results are discussed.

纳米粒子增强型离子液体 (NEIL) 是用于直接吸收太阳能集热器的新型传热流体，由基础离子液体 (IL) 中体积/重量百分比较小的纳米粒子组成。在本论文中，NEILs 是通过将 Al ₂ O ₃纳米颗粒分散在 1-丁基-3-甲基咪唑鎓双{(三氟甲基)磺酰亚胺 ([C ₄ mim] [NTf ₂ ]) ILs 中合成的。用不同尺寸和形状（一种尺寸为 10 × 100 nm 的棒状和四种尺寸为 10 nm、30 nm、60 nm 和 90 nm 的球形）的 Al ₂ O ₃研究了 NEIL 的辐射特性纳米粒子。合成了五种不同浓度（0.02%、0.04%、0.06%、0.08% 和 0.1% wt）的 NEIL，以研究浓度对辐射特性的影响。Al ₂ O ₃纳米颗粒的加入大大提高了离子液体[C ₄ mim][NTf _{2 的}吸光能力]，仅使用 0.02% wt 的纳米颗粒观察到透射率至少降低 26%。UV-vis 吸收的差异在较小的浓度下更为明显；纳米颗粒类型之间的差异高达 20%，而较大浓度的纳米颗粒之间的透射率差异仅为 5%。由棒状纳米粒子制成的纳米流体通常在 0.02%、0.04% 和 0.06% 重量的纳米粒子中产生更高的百分比透射率值，因此吸收光的能力较差。由 10 nm 球形纳米粒子制成的纳米流体在较高浓度下产生较小的百分比透射率值，在 0.1% wt 时的透射率低至 2.7%，因此能够更好地吸收光。在完成纳米颗粒尺寸和形状研究后，₂ mim][NTf ₂ ]、[C ₆ mim][NTf ₂ ] 和 [C ₁₀ mim][NTf ₂ ] IL。该研究表明，随着碳链长度的增加，透光率百分比增加。[C ₂ mim][NTf ₂ ] 被确定为吸收性最好的 NEILs，其透射率低至 2.2%。讨论了实验结果的合理原因。