Aouami Asmae El, Pérez Laura M, Feddi Kawtar, El-Yadri Mohamed, Dujardin Francis, Suazo Manuel J, Laroze David, Courel Maykel, Feddi El Mustapha
Group of Optoelectronic of Semiconductors and Nanomaterials, ENSAM, Mohammed V University in Rabat, Rabat 10100, Morocco.
Instituto de Alta Investigación, CEDENNA, Universidad de Tarapacá, Casilla 7 D, Arica 1000000, Chile.
Nanomaterials (Basel). 2021 May 17;11(5):1317. doi: 10.3390/nano11051317.
Solar cells that are based on the implementation of quantum dots in the intrinsic region, so-called intermediate band solar cells (IBSCs), are among the most widely used concepts nowadays for achieving high solar conversion efficiency. The principal characteristics of such solar cells relate to their ability to absorb low energy photons to excite electrons through the intermediate band, allowing for conversion efficiency exceeding the limit of Shockley-Queisser. IBSCs are generating considerable interest in terms of performance and environmental friendliness. However, there is still a need for optimizing many parameters that are related to the solar cells, such as the size of quantum dots, their shape, the inter-dot distance, and choosing the right material. To date, most studies have only focused on studying IBSC composed of cubic shape of quantum dots. The main objective of this study is to extend the current knowledge of IBSC. Thus, we analyze the effect of the shape of the quantum dot on the electronic and photonic characteristics of indium nitride and indium gallium nitride multiple quantum dot solar cells structure considering cubic, spherical, and cylindrical quantum dot shapes. The ground state of electrons and holes energy levels in quantum dot are theoretically determined by considering the Schrödinger equation within the effective mass approximation. Thus, the inter and intra band transitions are determined for different dot sizes and different inter dot spacing. Consequently, current-voltage (J-V) characteristic and efficiencies of these devices are evaluated and compared for different shapes. Our calculations show that, under fully concentrated light, for the same volume of different quantum dots (QD) shapes and a well determined In-concentration, the maximum of the photovoltaic conversion efficiencies reaches 63.04%, 62.88%, and 62.43% for cubic, cylindrical, and spherical quantum dot shapes, respectively.
基于在本征区域中实现量子点的太阳能电池，即所谓的中间带太阳能电池（IBSC），是目前为实现高太阳能转换效率而应用最广泛的概念之一。此类太阳能电池的主要特性在于其吸收低能量光子以通过中间带激发电子的能力，从而使转换效率超过肖克利-奎塞尔极限。IBSC在性能和环境友好性方面引发了极大的关注。然而，仍有必要优化许多与太阳能电池相关的参数，例如量子点的尺寸、形状、点间距，以及选择合适的材料。迄今为止，大多数研究仅专注于研究由立方体形量子点构成的IBSC。本研究的主要目的是扩展当前对IBSC的认识。因此，我们分析了量子点形状对氮化铟和氮化铟镓多量子点太阳能电池结构的电子和光子特性的影响，其中考虑了立方体形、球形和圆柱形量子点形状。通过在有效质量近似下考虑薛定谔方程，从理论上确定了量子点中电子和空穴能级的基态。因此，确定了不同点尺寸和不同点间距下的带间和带内跃迁。进而，针对不同形状评估并比较了这些器件的电流-电压（J-V）特性和效率。我们的计算表明，在全聚光条件下，对于相同体积的不同量子点（QD）形状以及确定的铟浓度，立方体形、圆柱形和球形量子点形状的光伏转换效率最大值分别达到63.04%、62.88%和62.43%。
