Incorporation of Mn(2+) into CdSe quantum dots by chemical bath co-deposition method for photovoltaic enhancement of quantum dot-sensitized solar cells

A photoelectric conversion efficiency (PCE) of 4.9% was obtained under 100 mW cm(−2) illumination by quantum-dot-sensitized solar cells (QDSSCs) using a CdS/Mn : CdSe sensitizer. CdS quantum dots (QDs) were deposited on a TiO(2) mesoporous oxide film by successive ionic layer absorption and reaction. Mn(2+) doping into CdSe QDs is an innovative and simple method—chemical bath co-deposition, that is, mixing the Mn ion source with CdSe precursor solution for Mn : CdSe QD deposition. Compared with the CdS/CdSe sensitizer without Mn(2+) incorporation, the PCE was increased from 3.4% to 4.9%. The effects of Mn(2+) doping on the chemical, physical and photovoltaic properties of the QDSSCs were investigated by energy dispersive spectrometry, absorption spectroscopy, photocurrent density–voltage characteristics and electrochemical impedance spectroscopy. Mn-doped CdSe QDs in QDSSCs can obtain superior light absorption, faster electron transport and slower charge recombination than CdSe QDs.