Incorporation of Mn2+ 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 mWcm−2 illumination by using quantum-dot-sensitized solar cells (QDSSCs) using a CdS/Mn:CdSe sensitizer. CdS quantum dots (QDs) were deposited on the TiO2 mesoporous oxide film by successive ionic layer absorption and reaction. Mn2+ 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 Mn2+ incorporation, the PCE was increased from 3.4% to 4.9%. The effects of Mn2+ 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.

本研究采用CdS/Mn:CdSe敏化剂制备量子点敏化太阳能电池（QDSSCs），在100 mW·cm⁻²光照条件下获得了4.9%的光电转换效率（PCE）。通过连续离子层吸附与反应法，将硫化镉量子点（QDs）沉积于二氧化钛介孔氧化物薄膜表面。针对CdSe量子点的Mn²+掺杂采用一种创新且简便的方法——化学浴共沉积，即将Mn离子源与CdSe前驱体溶液混合以沉积Mn:CdSe量子点。与未掺杂Mn²+的CdS/CdSe敏化体系相比，该器件的光电转换效率从3.4%提升至4.9%。本研究通过能量色散光谱、吸收光谱、光电流密度-电压特性以及电化学阻抗谱，探究了Mn²+掺杂对QDSSCs的化学、物理及光伏性能的影响。相较于纯CdSe量子点，QDSSCs中掺杂Mn的CdSe量子点可实现更优异的光吸收能力、更快的电子传输速率以及更缓慢的电荷复合过程。