Influence of Geometrical Shape on the Characteristics of the Multiple InN/InxGa1−xN Quantum Dot Solar Cells

Abstract

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.

Parameters Optimization of Intermediate Band Solar Cells: Cases of PbTe/CdTe, PbSe/ZnTe and InN/GaN Quantum Dots

“…Let us recall that in our last study published recently [44], we developed an analytical calculation of efficiency in three types of QD shapes (cubic, spherical and cylindrical); we demonstrated that the efficiency is not very sensitive to the geometrical shape. Therefore, and for simplicity, we only analyze the case of cubic QDs.…”

A model‐based systems engineering framework for quantum dot solar cells development

“…They have unique electronic properties, which can be tuned during manufacturing by simply changing the dot shape and size 19 . A quantum dot solar cell is obtained by incorporating quantum dots into the absorbing photovoltaic material 20 . Using a well‐tuned solar cell, it is possible to absorb a wide range of the solar spectrum, which is typically difficult to achieve by conventional solar cells, and thus the efficiency of the solar cell is eventually enhanced 21 .…”

“…It should be noted that conventional solar cells were made of crystalline silicon and were able to attain an efficiency of up to 26%, which led to a long time of the return of investment. However, by using quantum dot solar cells with an optimized design, it is possible to achieve much higher efficiencies, 20 which makes it possible to successfully satisfy the stakeholder requirements. For instance, the time of return of investment for conventional solar cells is around 7–10 years in the United States.…”

Effects of an external electric field on the electronic and optical properties of a Cylindrical ZnS/ZnO multi-layer quantum dot with a parabolic potential

“…Recent advances in nano-fabrication technology have offered a wide range of opportunities for realizing quantum dots QD with various kind of shapes and confining potentials, which have attracted considerable attention due to their unique optical properties like broad absorption, tunable and narrow emission [1], as well as their potential applications in electronics and optoelectronic devices, such as solar cells [2,3], lasers [4,5], photodetectors [6], light emitting diodes (LEDs) [7] and bioimaging [8]. Today, multiple layered QDs are attracting widespread interest in modern materials science and technology, with far more advantages and tuning capabilities compared with a single QD material.…”

“…The study in Ref. [2] indicates that, by changing the shape of quantum dots, the performance of solar cells is slightly modified. Moreover, it has been demonstrated that the quantum dots size, and light concentration play a key role in searching the maximum efficiency of multiple quantum dot solar cells.…”