Water-soluble ZnSe/ZnS:Mn/ZnS quantum dots convert UV to visible light for improved Si solar cell efficiency

Abstract

The sensitivity of Si solar cells to the UV portion of the solar spectrum is low, and must be increased to further improve their efficiencies.

Hydrothermal synthesis of water-soluble Mn- and Cu-doped CdSe quantum dots with multi-shell structures and their photoluminescence properties

“…The ZnS:Mn precursor solution was prepared according to a previous report. 21 First, Zn(ClO 4 ) 2 ·6H 2 O (1.2 mmol) and NAC (8.7 mmol) were dissolved in 20 mL of DI water. NaOH was added to adjust the pH to 4.0, and Na 2 S·9H 2 O (0.24 mmol) and Mn(ClO 4 ) 2 ·6H 2 O (0.18 mmol) were added.…”

“…1–5 Furthermore, new optical and magnetic properties can be imparted to QDs by doping with transition metal ions. 6–9 Therefore, transition metal-doped quantum dots (doped QDs) have attracted attention in various fields, such as highly efficient photoluminescent materials, 6,7,10–15 wavelength conversion materials, 16–21 and spin-photonics. 22–28 Focusing on the optical properties of doped QDs, their photoluminescence (PL) properties can be controlled by doping with Mn or Cu ions.…”

“…We previously used a hydrothermal method to synthesize ZnSe/ZnS:Mn/ZnS core/shell/shell QDs with a PL quantum yield (PLQY) of 84%. 21 Instead of directly doping the core, Mn 2+ doping was carried out in a shell layer over non-doped ZnSe core QDs as the host. Because this method separates the host synthesis from the doping process, it could be applied to various types of doped QDs with different host materials and QD sizes.…”

“… 51 Nevertheless, it is not easy to synthesize doped QDs with both strong Mn PL and controlled QD size. This problem could be overcome using our previously proposed method, 21 in which the non-doped core QDs are prepared independently and then two shell layers including a doped one are deposited to form the core/shell/shell QDs. In other words, because the QD size of the host CdSe core ( i.e.…”

Bandgap-tuned fluorescent CuGaS2/ZnS core/shell quantum dots for photovoltaic applications

“…16–18 Moreover, an improvement of 7.4% was reported for an LDS layer by using ZnSe/ZnS:Mn 2+ /ZnS QDs. 20…”