热载流子多结太阳能电池CdSe/CdS核壳量子点和纳米片的声子瓶颈效应机理  

Mechanism of phonon bottleneck effect in CdSe/CdS core-shell quantum dots and nanoplatelets of hot-carrier multi-junction solar cells

作　　者：王睿[1] 张琛浩 徐苏悦 张怿 Wang Rui;Zhang Chenhao;Xu Suyue;Zhang Yi(College of Renewable Energy,Hohai University,Nanjing 210098,China)

机构地区：[1]河海大学新能源学院,江苏南京210098

出　　处：《新能源科技》2024年第2期26-33,共8页New energy technology

基　　金：国家级大学生创新创业训练计划(202310294045Z);固体微结构物理国家重点实验室开放基金(M35060);江苏省科技计划“港澳台科技合作”专项项目(BZ2021057)。

摘　　要：热载流子多结太阳能电池(HCMJSC)是热载流子及叠层电池概念相结合而提出的一种较有前景的第三代太阳能电池之一,其理论效率在一个标准太阳条件(即1000 W/m 2,25℃)下将高于65%,远高于32%的单节硅基电池极限效率。该型电池主要包括一个宽带隙的顶结薄膜和一个适中带隙的厚底结基底,以分别高效吸收利用高能和低能光子。其广泛应用于光电器件的宽带隙CdSe/CdS低维材料体系(如量子点、纳米片等)有望成为顶结薄膜的合适候选材料。然而,该材料体系中的声子瓶颈效应(PBE)机理目前尚不明晰。文章主要研究了CdSe/CdS核壳量子点(QDs)和纳米片(NPLs)中的PBE机理;通过稳态光致发光(SSPL)和皮秒时间分辨尺度光致发光(ps-TRPL)技术,计算该材料体系的热弛豫系数(Q th),从而定量分析激发载流子的弛豫速率,同时阐述了PBE和量子点中常见的俄歇复合之间的耦合关系,最终系统研究了QDs和NPLs中载流子弛豫过程机理,提出HCMJSC的发展路径和建议。The hot carrier multi-junction solar cell(HCMJSC)is one of the most promising third generation solar cells proposed by combining the concepts of the hot carrier and tandem solar cell.Its theoretical efficiency will be higher than 65%in one sun standard solar condition,much higher than limit efficiency of a single silicon based solar cell(i.e.32%).The HCMJSC typically includes a wide bandgap top junction thin film and a thick bottom junction substrate with moderate band gap to absorb high and low energy photons,respectively.The wide-band gap CdSe/CdS low-dimensional systems(e.g.quantum dots,nanoplatelets,etc.)widely used in optoelectronic devices are expected to be suitable candidates for top-junction thin films.However,the mechanisms of the phonon bottleneck effect(PBE)of HCMJSC in such material system is still not well understood.This work mainly studies the PBE mechanism of CdSe/CdS core-shell quantum dots(QDs)and nanoplatelets(NPLs).The calculation of the thermalization coefficient(Q th)of the material system and quantitative analysis of PBE were carried out by steady state photoluminescence(SSPL)and picosecond-time resolved photoluminescence(ps-TRPL).So that the systematical study the mechanism of carrier relaxation process in QDs and NPLs could be completed,and put forward the development path and suggestions of HCMJSC.

关 键 词：声子瓶颈效应(PBE) 二六族半导体(Ⅱ-Ⅵsemiconductors) 量子点(QDs) 纳米片(NPLs) 热弛豫系数(Q th) 皮秒时间光致发光(ps-TRPL) 

分 类 号：TM914[电气工程—电力电子与电力传动]