arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1602.04236cond-mat.mtrl-sci
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载流子迁移率和能带取向对胶体量子点太阳能电池效率的影响

Role of Carrier Mobility and Band Alignment Engineering on the Efficiency of Colloidal Quantum Dot Solar Cells

Roha Saad, Nauman Z. Butt

摘要:

我们研究基于物理的胶体量子点(CQD)太阳能电池的设计,使用自洽的计算模型。定量地探讨了带取向工程和优化载流子迁移率的意义,作为在体CQD中的亚带隙缺陷密度(N_t)的函数。对于$N_t \leq 10^{15} cm^{-3}$,在CQD和金属接触界面附近的能带对准工程可以通过抑制正向偏压暗电流来显著提高开路电压。对于较薄的$(< 1 μm)$ CQD层,该效应可将电池效率提高至约37%。对于较厚的$(> 1 μm)$ CQD层,能带工程的影响被减弱,因为正向偏压暗电流变得扩散受限并且较少依赖于界面能带偏移。CQD中的最佳载流子迁移率在~ 10^{-2} cm ^2/Vs - 10^0 cm ^2/Vs的范围内,并且显示出作为CQD层厚度和界面带偏移的函数的变化。对于$N_t \approx 10^{14} cm^{-3}$,最佳设计的电池可以在AM 1.5G太阳光谱下提供约20%的效率,而不采用先进的结构优化,如纳米结构电极。这些物理见解有助于更好地理解量子点太阳能电池设计,从而进一步实现高效和低成本的太阳能电池技术。

英文摘要:

We investigate physics based design of colloidal quantum dot (CQD) solar cells using self-consistent computational modeling. The significance of band alignment engineering and optimized carrier mobility are quantitatively explored as a function of sub bandgap defect densities (N_t) in the bulk CQD. For $N_t \leq 10^{15} cm^{-3}$, band alignment engineering near the interface of CQD and the metal contact could significantly improve open circuit voltage by suppressing the forward bias dark current. This effect could enhance cell efficiency up to ~37% for thinner $(< 1 μm)$ CQD layers. For thicker $(> 1 μm)$ CQD layer, the effect of band engineering is diminished as the forward bias dark current becomes diffusion-limited and less dependent on the interfacial band offsets. An optimal carrier mobility in CQD lies in the range ~ 10^{-2} cm^2/Vs - 10^0 cm^2/Vs and shows variation as a function of CQD layer thickness and the interfacial band offset. For $N_t \approx 10^{14} cm^{-3}$, an optimally designed cell could provide ~20% efficiency under AM1.5G solar spectrum without employing advanced structural optimizations such as the nanostructured electrodes. These physical insights contribute to a better understanding of quantum dot solar cell design, allowing a step further towards a highly efficient and a low cost solar cell technology.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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