scholarly journals Size-Dependent and Enhanced Photovoltaic Performance of Solar Cells Based on Si Quantum Dots

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4845
Author(s):  
Yunqing Cao ◽  
Ping Zhu ◽  
Dongke Li ◽  
Xianghua Zeng ◽  
Dan Shan
Keyword(s):  
Quantum Dots ◽  
Solar Cells ◽  
Light Trapping ◽  
Spectral Response ◽  
Quantum Confinement Effect ◽  
Strong Dependence ◽  
Photovoltaic Performance ◽  
Heterojunction Solar Cells ◽  
Optical Absorption Measurement ◽  
Si Quantum Dots

Recently, extensive studies have focused on exploring a variety of silicon (Si) nanostructures among which Si quantum dots (Si QDs) may be applied in all Si tandem solar cells (TSCs) for the time to come. By virtue of its size tunability, the optical bandgap of Si QDs is capable of matching solar spectra in a broad range and thus improving spectral response. In the present work, size-controllable Si QDs are successfully obtained through the formation of Si QDs/SiC multilayers (MLs). According to the optical absorption measurement, the bandgap of Si QDs/SiC MLs shows a red shift to the region of long wavelength when the size of dots increases, well conforming to quantum confinement effect (QCE). Additionally, heterojunction solar cells (HSCs) based on Si QDs/SiC MLs of various sizes are presented and studied, which demonstrates the strong dependence of photovoltaic performance on the size of Si QDs. The measurement of external quantum efficiency (EQE) reveals the contribution of Si QDs to the response and absorption in the ultraviolet–visible (UV-Vis) light range. Furthermore, Si QDs/SiC MLs-based solar cell shows the best power conversion efficiency (PCE) of 10.15% by using nano-patterned Si light trapping substrates.

Enhanced broadband spectral response and energy conversion efficiency for hetero-junction solar cells with graded-sized Si quantum dots/SiC multilayers

2015 ◽  
Vol 3 (46) ◽  
pp. 12061-12067 ◽  
Author(s):  
Yunqing Cao ◽  
Jun Xu ◽  
Zhaoyun Ge ◽  
Yingying Zhai ◽  
Wei Li ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Solar Cells ◽  
Energy Conversion ◽  
Conversion Efficiency ◽  
Spectral Response ◽  
Energy Conversion Efficiency ◽  
Cell Performance ◽  
Novel Structure ◽  
Si Quantum Dots

We propose a novel structure of a graded-sized Si QDs/Si hetero-junction cell, which exhibits broadband spectral response and improved cell performance.

Preparation of B-doped Si quantum dots embedded in SiNx films for Si quantum dot solar cells

2018 ◽  
Vol 32 (02) ◽  
pp. 1850003
Author(s):  
Xiaobo Chen ◽  
Peizhi Yang
Keyword(s):  
Quantum Dots ◽  
Solar Cells ◽  
Photovoltaic Performance ◽  
Doping Amount ◽  
Photovoltaic Properties ◽  
Heterojunction Solar Cells ◽  
Si Quantum Dot ◽  
Quantum Dot Solar Cells ◽  
The Matrix ◽  
B Doping

Silicon quantum dots (Si-QDs) embedded B-doped SiN[Formula: see text] films were fabricated by magnetron co-sputtering. The effects of B content on the structural, optical and electrical properties of the films were studied. The study found that the amount of B dopant has no significant effect on the crystallization characteristics of the films. B atoms may be doped in the Si-QDs or exist in the silicon nitride or the interface between Si-QDs and the matrix. PL intensity increases with increasing B content, but increases at first and then decreases. The conductivity as a function of the dopant concentration increases at first from a value of 2.71 × 10[Formula: see text] S/cm to 5.83 × 10[Formula: see text] S/cm until 0.9 at.% and then decreases. By employing B-doped Si-QDs films, Si-QDs/c-Si heterojunction solar cells were fabricated and the effect of B doping concentration on the photovoltaic properties was studied. It was found that, with the increase of B doping amount, the photovoltaic performance is improved, when the B doping amount is 0.9 at.%, the efficiency reaches the highest value of 4.26%.

scholarly journals Boosting Photovoltaic Performance in Organic Solar Cells by Manipulating the Size of MoS2 Quantum Dots as a Hole-Transport Material

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1464
Author(s):  
Kwang Hyun Park ◽  
Sunggyeong Jung ◽  
Jungmo Kim ◽  
Byoung-Min Ko ◽  
Wang-Geun Shim ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Solar Cells ◽  
Organic Solar Cells ◽  
High Performance ◽  
Quantum Confinement Effect ◽  
Critical Role ◽  
Photovoltaic Performance ◽  
Hole Transport ◽  
Transport Layer ◽  
Hole Transport Layer

The design of photoactive materials and interface engineering between organic/inorganic layers play a critical role in achieving enhanced performance in energy-harvesting devices. Two-dimensional transitional dichalcogenides (TMDs) with excellent optical and electronic properties are promising candidates in this regard. In this study, we demonstrate the fabrication of size-controlled MoS2 quantum dots (QDs) and present fundamental studies of their optical properties and their application as a hole-transport layer (HTL) in organic solar cells (OSCs). Optical and structural analyses reveal that the as-prepared MoS2 QDs show a fluorescence mechanism with respect to the quantum confinement effect and intrinsic/extrinsic states. Moreover, when incorporated into a photovoltaic device, the MoS2 QDs exhibit a significantly enhanced performance (5/10-nanometer QDs: 8.30%/7.80% for PTB7 and 10.40%/10.17% for PTB7-Th, respectively) compared to those of the reference device (7.24% for PTB7 and 9.49% for PTB7-Th). We confirm that the MoS2 QDs clearly offer enhanced transport characteristics ascribed to higher hole-mobility and smoother root mean square (Rq) as a hole-extraction material. This approach can enable significant advances and facilitate a new avenue for realizing high-performance optoelectronic devices.

scholarly journals Size-dependent Photovoltaic Properties of Solar Cells Containing Si Quantum Dots/SiC Multilayers

2020 ◽  
Author(s):  
Yunqing Cao ◽  
Dong Wu ◽  
Ping Zhu ◽  
Zhaoyun Ge ◽  
Wei Li ◽  
...  
Keyword(s):  
Solar Cells ◽  
Spectral Response ◽  
Quantum Confinement Effect ◽  
Solar Spectrum ◽  
Visible Range ◽  
Photovoltaic Properties ◽  
Heterojunction Solar Cells ◽  
Size Dependent ◽  
Wide Range ◽  
Si Nanostructures

Abstract Recently, many kinds of Si nanostructures have been extensively investigated, in which, Si quantum dot (Si QD) is one of the potential candidates for all-Si tandem solar cells. Because the optical bandgap of Si QDs can be tunable via size controlling, it can match the solar spectrum in a wide range and consequently improve the spectral response. In this work, Si QDs/SiC multilayers with controllable dot sizes were fabricated and characterized. The Raman spectra and transmission electron microscopy (TEM) observation revealed the formation of size-controllable Si QDs. The absorption measurement showed that the bandgap of Si QDs was red shifted to the long wavelength range with the dot size increasing, which agrees well with the quantum confinement effect. Moreover, heterojunction solar cells containing different sized-Si QDs/SiC multilayers were proposed and investigated. The solar cells exhibited strong size-dependent photovoltaic properties and the best cell had the power conversion efficiency (PCE) of 7.27%. Furthermore, the external quantum efficiency (EQE) measurement demonstrated the Si QDs contribution of light absorption and response in ultraviolet-visible range, which provides a promising way to realize better spectral match by applying different sized-Si QDs in the future photovoltaic devices.

scholarly journals Effects of CsSnxPb1−xI3 Quantum Dots as Interfacial Layer on Photovoltaic Performance of Carbon-Based Perovskite Solar Cells

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Chi Zhang ◽  
Zhiyuan He ◽  
Xuanhui Luo ◽  
Rangwei Meng ◽  
Mengwei Chen ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Solar Cells ◽  
Photovoltaic Performance ◽  
Perovskite Solar Cells ◽  
Photogenerated Electron ◽  
Depletion Region ◽  
Band Alignment ◽  
Back Surface ◽  
The One ◽  
Carbon Based

AbstractIn this work, inorganic tin-doped perovskite quantum dots (PQDs) are incorporated into carbon-based perovskite solar cells (PSCs) to improve their photovoltaic performance. On the one hand, by controlling the content of Sn2+ doping, the energy level of the tin-doped PQDs can be adjusted, to realize optimized band alignment and enhanced separation of photogenerated electron–hole pairs. On the other hand, the incorporation of tin-doped PQDs provided with a relatively high acceptor concentration due to the self-p-type doping effect is able to reduce the width of the depletion region near the back surface of the perovskite, thereby enhancing the hole extraction. Particularly, after the addition of CsSn0.2Pb0.8I3 quantum dots (QDs), improvement of the power conversion efficiency (PCE) from 12.80 to 14.22% can be obtained, in comparison with the pristine device. Moreover, the experimental results are analyzed through the simulation of the one-dimensional perovskite/tin-doped PQDs heterojunction.

Role of Surface Band Gap Widening in Cu(In, Ga)(Se, S)2 Thin-Films for the Photovoltaic Performance of ZnO/CdS/Cu(In, Ga)(Se, S)2 Heterojunction Solar Cells

2003 ◽  
Vol 763 ◽  
Author(s):  
U. Rau ◽  
M. Turcu
Keyword(s):  
Thin Films ◽  
Surface Layer ◽  
Solar Cells ◽  
Fermi Level ◽  
Band Gap ◽  
Photovoltaic Performance ◽  
Heterojunction Solar Cells ◽  
Fermi Level Pinning ◽  
Device Efficiency

AbstractNumerical simulations are used to investigate the role of the Cu-poor surface defect layer on Cu(In, Ga)Se2 thin-films for the photovoltaic performance of ZnO/CdS/Cu(In, Ga)Se2 heterojunction solar cells. We model the surface layer either as a material which is n-type doped, or as a material which is type-inverted due to Fermi-level pinning by donor-like defects at the interface with CdS. We further assume a band gap widening of this layer with respect to the Cu(In, Ga)Se2 bulk. This feature turns out to represent the key quality of the Cu(In, Ga)Se2 surface as it prevents recombination at the absorber/CdS buffer interface. Whether the type inversion results from n-type doping or from Fermi-level pinning is only of minor importance as long as the surface layer does not imply a too large number of excess defects in its bulk or at its interface with the normal absorber. With increasing number of those defects an n-type layer proofs to be less sensitive to material deterioration when compared to the type-inversion by Fermi-level pinning. For wide gap chalcopyrite solar cells the internal valence band offset between the surface layer and the chalcopyrite appears equally vital for the device efficiency. However, the unfavorable band-offsets of the ZnO/CdS/Cu(In, Ga)Se2 heterojunction limit the device efficiency because of the deterioration of the fill factor.

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