Giant photocurrent enhancement by transition metal doping in quantum dot sensitized solar cells

Abstract

A huge enhancement in the incident photon-to-current efficiency of PbS quantum dot (QD) sensitized solar cells by manganese doping is observed. In the presence of Mn dopants with relatively small concentration (4 at. %), the photoelectric current increases by an average of 300% (up to 700%). This effect cannot be explained by the light absorption mechanism because both the experimental and theoretical absorption spectra demonstrate several times decreases in the absorption coefficient. To explain such dramatic increase in the photocurrent we propose the electron tunneling mechanism from the LUMO of the QD excited state to the Zn 2 SnO 4 (ZTO) semiconductor photoanode. This change is due to the presence of the Mn instead of Pb atom at the QD/ZTO interface. The ab initio calculations confirm this mechanism. This work proposes an alternative route for a significant improvement of the efficiency for quantum dot sensitized solar cells.

Quantum dot-sensitized solar cells

“…[296][297][298][299][300][301] The effect of dopant in QDs sensitizer has also been investigated in QDSCs. 107,185,191,203,246,[302][303][304][305][306][307][308][309][310][311][312] In 2012, Kamat and coworkers introduced the doping strategy in QDs and studied doping effect on the photovoltaic performance in QDSCs (Fig. 19).…”

Influence of the Cation on the Surface Electronic Band Structure and Magnetic Properties of Mn:ZnS and Mn:CdS Quantum Dot Thin Films

“…Semiconducting quantum dots (QDs) are viable materials for next-generation solar cells as they have size-dependent optical and electronic properties because of quantum confinement, effectively allowing for variability of the optical and electronic band gaps. − Transition-metal doping in solar cell materials is another useful method for tailoring the optical, electronic, and magnetic properties of QDs beyond just changing the size. Historically, pure semiconducting QDs are known to produce low device performance, , but recently, it was shown that transition-metal dopants, specifically Mn, can be used to improve the overall device performance − in QD-sensitized solar cells. Transition-metal-doped QD semiconductors fall under the category of dilute magnetic semiconductors (DMSs).…”

Effect of Cu doping and swift heavy ion irradiation on PbS quantum dots and their applications in solar cells

“…The reason for an improved current density (J sc ) in the copper doped and irradiated PbS QD solar cell [17], can be attributed to the unique electronic configuration of copper ([Ar]4s 2 3d 10 ).…”