Nano Lett 2006, 6:1529–1534.CrossRef 22. Gao JW, Zheng RT, Ohtani H, Zhu DS, Chen G: Experimental investigation

S3I-201 of heat conduction mechanics in nanofluids. Clue on clustering. Nano Lett 2009, 9:4128–4132.CrossRef 23. Zhu H, Zhang C, Liu S, Tang Y, Yin Y: Effects of nanoparticle clustering and alignment on thermal conductivities of Fe[sub 3]O[sub 4] aqueous nanofluids. Appl Phys Lett 2006, 89:023123.CrossRef 24. Xie H, Fujii M, Zhang X: Effect of interfacial nanolayer on the effective thermal conductivity of nanoparticle-fluid mixture. Int J Heat Mass Transf 2005, 48:2926–2932.CrossRef 25. Lin Y-S, Hsiao P-Y, Chieng C-C: Roles of nanolayer and particle size on thermophysical characteristics of ethylene glycol-based copper nanofluids. Appl Phys Lett 2011, 98:153105.CrossRef 26. Yu W, Choi SUS: The role of interfacial layers in the enhanced thermal conductivity of nanofluids: a renovated JQ1 research buy Maxwell model. J Nanopart Res 2003, 5:167–171.CrossRef 27. Ishida H, Rimdusit S: Heat capacity measurment of boron nitride-filled polybenzoxazine: the composite structure-insensitive property. J Therm Anal Calorim 1999, 58:497–507.CrossRef 28. Xue L, Keblinski P, Phillpot SR, Choi SUS, Eastman JA: Two regimes of thermal resistance at a liquid–solid interface. J Chem Phys 2003, 118:337–339.CrossRef Competing

interests The authors declare that they have no competing interests. Authors’ contributions The manuscript was written through contributions of all authors. All authors have given approval to GSK2245840 the final version of the manuscript.”
“Background Commercial solar cells employ only a small portion of the solar spectrum for photoelectric conversion, with the available wavelengths covering the visible to near-infrared (NIR) regimes [1]. To fully use the solar emission energy, various light frequency-conversion approaches

have been proposed [2–17], which convert IR or ultraviolet (UV) lights into visible ones, the so called up- and down-conversions, respectively. So far, the photoluminescence (PL) conversion, as a type of down-conversion, seems more potentially available in solar cell efficiency enhancement. from However, its practical use is actually uncertain, as other factors such as antireflection (AR) might also contribute to the efficiency enhancement in addition to the PL conversion, making the assessment of real contribution from PL conversion doubtful [6, 9–14]. Although in our recent work [10], we have noticed this problem and tried to single out the contribution of PL conversion, systematic studies and convincing experimental facts are still lacking. This work aims to solve the puzzling problem by offering a combined approach and evaluating how important on earth the PL conversion could be in improving solar cell efficiency. We selected a material with high PL conversion efficiency (> 40%), i.e., Mn-doped ZnSe quantum dots (Mn:ZnSe QDs).