Das Aparajita, Deepa Melepurath, Ghosal Partha
Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi-, 502285, Sangareddy, Telangana, India.
Defence Metallurgical Research Laboratory, DRDO, Hyderabad, 500058, Telangana, India.
Chemphyschem. 2017 Apr 5;18(7):736-748. doi: 10.1002/cphc.201601284. Epub 2017 Feb 6.
Lead-sulfide-selenide (PbSSe) quantum dots (QDs) and gold-copper (AuCu) alloy nanoparticles (NPs) were incorporated into a cadmium sulfide (CdS)/titanium oxide (TiO ) photoanode for the first time to achieve enhanced conversion of solar energy into electricity. PbSSe QDs with a band gap of 1.02 eV extend the light-harvesting range of the photoanode from the visible region to the near-infrared region. The conduction band (CB) edge of the PbSSe QDs is wedged between the CBs of TiO and CdS; this additional level coupled with the good electrical conductivity of the dots facilitate charge transport and collection, and a high power conversion efficiency (PCE) of 4.44 % is achieved for the champion cell with the TiO /PbSSe/CdS electrode. Upon including AuCu alloy NPs in the QD-sensitized electrodes, light absorption is enhance by plasmonic and light-scattering effects and also by the injection of hot electrons to the CBs of the QDs. Comparison of the incident photon-to-current conversion efficiency enhancement factors in addition to fluorescence decay and impedance studies reveal that the PbSSe QDs and AuCu alloy NPs promote charge injection to the current collector and increase the photogenerated charges produced, which thus enables the TiO /PbSSe/CdS/AuCu cell to deliver the highest PCE of 5.26 % among all the various photoanode compositions used.
首次将硫化铅 - 硒化物（PbSSe）量子点（QDs）和金 - 铜（AuCu）合金纳米颗粒（NPs）引入硫化镉（CdS）/氧化钛（TiO₂）光阳极中，以实现太阳能到电能的增强转换。带隙为1.02 eV的PbSSe量子点将光阳极的光捕获范围从可见光区域扩展到近红外区域。PbSSe量子点的导带（CB）边缘楔入TiO₂和CdS的导带之间；这个额外的能级加上量子点良好的导电性促进了电荷传输和收集，使用TiO₂/PbSSe/CdS电极的最佳电池实现了4.44%的高功率转换效率（PCE）。在量子点敏化电极中加入AuCu合金纳米颗粒后，通过等离子体和光散射效应以及向量子点导带注入热电子，光吸收得到增强。除了荧光衰减和阻抗研究外，对入射光子到电流转换效率增强因子的比较表明，PbSSe量子点和AuCu合金纳米颗粒促进了电荷注入到集电器中，并增加了产生的光生电荷，从而使TiO₂/PbSSe/CdS/AuCu电池在所有使用的各种光阳极组成中提供了最高的5.26%的PCE。
