In this study, we have prepared and investigated the optical properties of the TiO2/CdS:Mn2+/CdSe photoanode as the function of Mn2+ doping concentration and thickness. The results show that the peaks of the UV-Vis spectra shifted toward longer wavelength while Mn2+ doping concentrations or thickness of the films were changed. | VNU Journal of Science: Mathematics – Physics, Vol. 34, No. 3 (2018) 33-42 Preparation and Characterization of Quantum Dots Sensitized Solar Cells Based on TiO2/CdS:Mn2+/CdSe Photoanode Ha Thanh Tung1,*, Nguyen Cong Hau2, Nguyen Tan Phat3, Lam Quang Vinh4 1 Faculty of Physics, DongThap University, Dong Thap Province, Vietnam 2 University of Science, VNU-HCM, Vietnam 3 Department of Physics, HCMC University of Education, Vietnam 4 Vietnam National University - HCM City, Vietnam Received 01 May 2018 Revised 30 May 2018; Accepted 20 June 2018 Abstract: In this study, we have prepared and investigated the optical properties of the TiO2/CdS:Mn2+/CdSe photoanode as the function of Mn2+ doping concentration and thickness. The results show that the peaks of the UV-Vis spectra shifted toward longer wavelength while Mn2+ doping concentrations or thickness of the films were changed. The main cause of the red-shifting in UV-Vis spectra may come from the increasing of photoanode light-harvesting capacity. In addition, the results also demonstrated by the boosting performance of quantum dots sensitized solar cells from for TiO2/CdS/CdSe photoanode to for TiO2/CdS:Mn2+/CdSe photoanode. Keywords: Solar cells, nano CdS, nano CdSe. 1. Introduction Quantum dots sensitized solar cells (QDSSCs) can be regarded as a derivative of dye sensitized solar cells (DSSCs) by replacing dye molecules with quantum dots (QDs). QDs have been chosen as a main photosensitizer in solar cells since they have several optical and electrical advantages, including: tunable band gap depending on the QD size due to the quantum confinement effect, higher absorption coefficient than most organic dyes, and multiple exciton generation (MEG) effect [1-3]. Moreover, QDs can generate multiple electron-hole pairs from a single incident photon absorption (MEG), which allowed the power conversion efficiency (PCE) of QDSSCs overcome the Shockley – Queisser limit of traditional Si solar cells. Therefore,
