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11 pages, 3589 KiB

Open AccessArticle

Effect of ZnO Nanoparticles Coating Layers on Top of ZnO Nanowires for Morphological, Optical, and Photovoltaic Properties of Dye-Sensitized Solar Cells

by Muhammad Saleem, W. A. Farooq, M. I. Khan, Majid. Niaz. Akhtar, Saif Ur Rehman, Naseeb Ahmad, Muhammad Khalid, M. Atif, Mona A. AlMutairi and Muhammad Irfan

Micromachines 2019, 10(12), 819; https://doi.org/10.3390/mi10120819 - 26 Nov 2019

Cited by 11 | Viewed by 2342

Abstract

This paper reports on the synthesis of ZnO nanowires (NWs), as well asthe compound nanostructures of nanoparticles (NPs) and nanowires (NWs+NPs) with different coating layers of NPs on the top of NWs and their integration in dye-sensitized solar cells (DSSCs). In compound nanostructures, [...] Read more.

This paper reports on the synthesis of ZnO nanowires (NWs), as well asthe compound nanostructures of nanoparticles (NPs) and nanowires (NWs+NPs) with different coating layers of NPs on the top of NWs and their integration in dye-sensitized solar cells (DSSCs). In compound nanostructures, NWs offer direct electrical pathways for fast electron transfer, and the NPs of ZnOdispread and fill the interstices between the NWs of ZnO, offering a huge surface area for enough dye anchoring and promoting light harvesting. A significant photocurrent density of 2.64 mA/cm² and energy conversion efficiency of 1.43% was obtained with NWs-based DSSCs. The total solar-to-electric energy conversion efficiency of the NWs+a single layer of NPs was found to be 2.28%, with a short-circuit photocurrent density (J_SC) of 3.02 mA/cm², open-circuit voltage (V_OC) of 0.74 V, and a fill factor (FF) of 0.76, which is 60% higher than that of NWs cells and over 165% higher than NWs+a triple layer of NPs-based DSSCs. The improved performance was obtained due to the increased specific surface area for higher dye anchoring and light harvesting of compound nanostructures with NWs+a single layer of NPs. Full article

(This article belongs to the Special Issue Nanostructured Photovoltaic Devices)

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11 pages, 5575 KiB

Open AccessArticle

Au-Embedded and Carbon-Doped Freestanding TiO₂ Nanotube Arrays in Dye-Sensitized Solar Cells for Better Energy Conversion Efficiency

by Won-Yeop Rho, Kang-Hun Lee, Seung-Hee Han, Hyo-Yeon Kim and Bong-Hyun Jun

Micromachines 2019, 10(12), 805; https://doi.org/10.3390/mi10120805 - 22 Nov 2019

Cited by 6 | Viewed by 2451

Abstract

Dye-sensitized solar cells (DSSCs) are fabricated with freestanding TiO₂ nanotube arrays (TNTAs) which are incorporated with Au nanoparticles (NPs) and carbon materials via electrodeposition and chemical vapor deposition (CVD) method to create a plasmonic effect and better electron transport that will enhance [...] Read more.

Dye-sensitized solar cells (DSSCs) are fabricated with freestanding TiO₂ nanotube arrays (TNTAs) which are incorporated with Au nanoparticles (NPs) and carbon materials via electrodeposition and chemical vapor deposition (CVD) method to create a plasmonic effect and better electron transport that will enhance their energy conversion efficiency (ECE). The ECE of DSSCs based on the freestanding TNTAs is 5.87%. The ECE of DSSCs, based on the freestanding TNTAs with Au NPs or carbon materials, is 6.57% or 6.59%, respectively, and the final results of DSSCs according to the freestanding TNTAs with Au NPs and carbon materials is increased from 5.87% to 7.24%, which is an enhancement of 23.34% owing to plasmonic effect and better electron transport. Au NPs are incorporated into the channel of freestanding TNTAs and are characterized by CS-corrected-field emission transmission electron microscope (Cs-FE-TEM) and elemental mapping. Carbon materials are also well-incorporated in the channel of freestanding TNTAs and are analyzed by Raman spectroscopy. Full article

(This article belongs to the Special Issue Nanostructured Photovoltaic Devices)

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11 pages, 3041 KiB

Open AccessArticle

Enhanced Efficiencies of Perovskite Solar Cells by Incorporating Silver Nanowires into the Hole Transport Layer

by Chien-Jui Cheng, Rathinam Balamurugan and Bo-Tau Liu

Micromachines 2019, 10(10), 682; https://doi.org/10.3390/mi10100682 - 10 Oct 2019

Cited by 14 | Viewed by 2849

Abstract

In this study, we incorporated silver nanowires (AgNWs) into poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) as a hole transport layer (HTL) for inverted perovskite solar cells (PVSCs). The effect of AgNW incorporation on the perovskite crystallization, charge transfer, and power conversion efficiency (PCE) of PVSCs were [...] Read more.

In this study, we incorporated silver nanowires (AgNWs) into poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) as a hole transport layer (HTL) for inverted perovskite solar cells (PVSCs). The effect of AgNW incorporation on the perovskite crystallization, charge transfer, and power conversion efficiency (PCE) of PVSCs were analyzed and discussed. Compared with neat PEDOT:PSS HTL, incorporation of few AgNWs into PEDOT:PSS can significantly enhance the PCE by 25%. However, the AgNW incorporation may result in performance overestimation due to the lateral charge transfer. The corrosion of AgNWs with a perovskite layer was discussed. Too much AgNW incorporation may lead to defects on the interface between the HTL and the perovskite layer. An extra PEDOT:PSS layer over the pristine PEDOT:PSS-AgNW layer can prevent AgNWs from corrosion by iodide ions. Full article

(This article belongs to the Special Issue Nanostructured Photovoltaic Devices)

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8 pages, 1367 KiB

Open AccessArticle

Fabrication of an Efficient Planar Organic-Silicon Hybrid Solar Cell with a 150 nm Thick Film of PEDOT: PSS

by Sami Iqbal, Dan Su, Yi Yang, Fahim Ullah, Huanli Zhou, Azam Hussain and Tong Zhang

Micromachines 2019, 10(10), 648; https://doi.org/10.3390/mi10100648 - 26 Sep 2019

Cited by 10 | Viewed by 2653

Abstract

Organic–inorganic hybrid solar cells composed of p-type conducting polymer poly (3,4-ethylene-dioxythiophene): polystyrenesulfonate (PEDOT: PSS) and n-type silicon (Si) have gained considerable interest in recent years. From this viewpoint, we present an efficient hybrid solar cell based on PEDOT: PSS and the planar Si [...] Read more.

Organic–inorganic hybrid solar cells composed of p-type conducting polymer poly (3,4-ethylene-dioxythiophene): polystyrenesulfonate (PEDOT: PSS) and n-type silicon (Si) have gained considerable interest in recent years. From this viewpoint, we present an efficient hybrid solar cell based on PEDOT: PSS and the planar Si substrate (1 0 0) with the simplest and cost-effective experimental procedures. We study and optimize the thickness of the PEDOT: PSS film to improve the overall performance of the device. We also study the effect of ethylene glycol (EG) by employing a different wt % as a solvent in the PEDOT: PSS to improve the device’s performance. Silver (Ag) was deposited by electron beam evaporation as the front and rear contacts for the solar cell device. The whole fabrication process was completed in less than three hours. A power conversion efficiency (PCE) of 5.1%, an open circuit voltage (Voc) of 598 mV, and a fill factor (FF) of 58% were achieved. Full article

(This article belongs to the Special Issue Nanostructured Photovoltaic Devices)

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21 pages, 9245 KiB

Open AccessArticle

Analysis and Optimization of a Microchannel Heat Sink with V-Ribs Using Nanofluids for Micro Solar Cells

by Ruijin Wang, Jiawei Wang and Weijia Yuan

Micromachines 2019, 10(9), 620; https://doi.org/10.3390/mi10090620 - 17 Sep 2019

Cited by 28 | Viewed by 4087

Abstract

It is crucial to control the temperature of solar cells for enhancing efficiency with the increasing power intensity of multiple photovoltaic systems. In order to improve the heat transfer efficiency, a microchannel heat sink (MCHS) with V-ribs using a water-based nanofluid as a [...] Read more.

It is crucial to control the temperature of solar cells for enhancing efficiency with the increasing power intensity of multiple photovoltaic systems. In order to improve the heat transfer efficiency, a microchannel heat sink (MCHS) with V-ribs using a water-based nanofluid as a coolant for micro solar cells was designed. Numerical simulations were carried out to investigate the flows and heat transfers in the MCHS when the Reynolds number ranges from 200 to 1000. The numerical results showed that the periodically arranged V-ribs can interrupt the thermal boundary, induce chaotic convection, increase heat transfer area, and subsequently improve the heat transfer performance of a MCHS. In addition, the preferential values of the geometric parameters of V-ribs and the physical parameters of the nanofluid were obtained on the basis of the Nusselt numbers at identical pump power. For MCHS with V-ribs on both the top and bottom wall, preferential values of V-rib are rib width

d / W = 1

, flare angle

α = 75 °

, rib height

h r / H = 0.3

, and ratio of two slant sides

b / a = 0.75

, respectively. This can provide sound foundations for the design of a MCHS in micro solar cells. Full article

(This article belongs to the Special Issue Nanostructured Photovoltaic Devices)

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7 pages, 11238 KiB

Open AccessArticle

Low Conductivity Decay of Sn–0.7Cu–0.2Zn Photovoltaic Ribbons for Solar Cell Application

by Kuan-Jen Chen, Fei-Yi Hung, Truan-Sheng Lui and Lin Hsu

Micromachines 2019, 10(8), 550; https://doi.org/10.3390/mi10080550 - 19 Aug 2019

Cited by 2 | Viewed by 2678

Abstract

The present study applied Sn–0.7Cu–0.2Zn alloy solders to a photovoltaic ribbon. Intermetallic compounds of Cu₆Sn₅ and Ag₃Sn formed at the Cu/solder/Ag interfaces of the module after reflow. Electron probe microanalyzer images showed that a Cu–Zn solid-solution layer (Zn [...] Read more.

The present study applied Sn–0.7Cu–0.2Zn alloy solders to a photovoltaic ribbon. Intermetallic compounds of Cu₆Sn₅ and Ag₃Sn formed at the Cu/solder/Ag interfaces of the module after reflow. Electron probe microanalyzer images showed that a Cu–Zn solid-solution layer (Zn accumulation layer) existed at the Cu/solder interface. After a 72 h current stress, no detectable amounts of Cu₆Sn₅ were found. However, a small increase in Ag₃Sn was found. Compared with a Sn–0.7Cu photovoltaic module, the increase of the intermetallic compounds thickness in the Sn–0.7Cu–0.2Zn photovoltaic module was much smaller. A retard in the growth of the intermetallic compounds caused the series resistance of the module to slightly increase by 9%. A Zn accumulation layer formed at the module interfaces by adding trace Zn to the Sn–0.7Cu solder, retarding the growth of the intermetallic compounds and thus enhancing the lifetime of the photovoltaic module. Full article

(This article belongs to the Special Issue Nanostructured Photovoltaic Devices)

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20 pages, 6691 KiB

Open AccessArticle

Nanostructured Fe,Co-Codoped MoO₃ Thin Films

by Olfa Kamoun, Amel Mami, Mohamed Aymen Amara, Ruxandra Vidu and Mosbah Amlouk

Micromachines 2019, 10(2), 138; https://doi.org/10.3390/mi10020138 - 20 Feb 2019

Cited by 21 | Viewed by 5073

Abstract

Molybdenum oxide (MoO₃) and Fe,Co-codoped MoO₃ thin films obtained by spray pyrolysis have been in-depth investigated to understand the effect of Co and Fe codoping on MoO₃ thin films. The effect of Fe and Co on the structural, morphological [...] Read more.

Molybdenum oxide (MoO₃) and Fe,Co-codoped MoO₃ thin films obtained by spray pyrolysis have been in-depth investigated to understand the effect of Co and Fe codoping on MoO₃ thin films. The effect of Fe and Co on the structural, morphological and optical properties of MoO₃ thin films have been studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy-dispersive X-ray analysis (EDAX), optical and photoluminescence (PL) spectroscopy, and electropyroelectric methods. The XRD patterns demonstrated the formation of orthorhombic α-MoO₃ by spray pyrolysis. SEM characterization has shown an increase in roughness of MoO₃ thin films by Fe and Co doping. Optical reflectance and transmittance measurements have shown an increase in optical band gap with the increase in Fe and Co contents. Thermal conductivity and thermal diffusivity of Fe,Co-doped MoO₃ were 24.10–25.86 Wm⁻¹K⁻¹ and 3.80 × 10⁻⁶–5.15 × 10⁻⁶ m²s⁻¹, respectively. MoO₃ thin films have shown PL emission. Doping MoO₃ with Fe and Co increases emission in the visible range due to an increase number of chemisorbed oxygen atoms. The photodegradation of an aqueous solution of methylene blue (MB) depended on the content of the codoping elements (Fe,Co). The results showed that a degradation efficiency of 90% was observed after 60 min for MoO₃: Fe 2%-Co 1%, while the degradation efficiency was about 35% for the undoped MoO₃ thin film. Full article

(This article belongs to the Special Issue Nanostructured Photovoltaic Devices)

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Review

Jump to: Research

18 pages, 3644 KiB

Open AccessReview

Nanostructures for Light Trapping in Thin Film Solar Cells

by Amalraj Peter Amalathas and Maan M Alkaisi

Micromachines 2019, 10(9), 619; https://doi.org/10.3390/mi10090619 - 17 Sep 2019

Cited by 120 | Viewed by 11366

Abstract

Thin film solar cells are one of the important candidates utilized to reduce the cost of photovoltaic production by minimizing the usage of active materials. However, low light absorption due to low absorption coefficient and/or insufficient active layer thickness can limit the performance [...] Read more.

Thin film solar cells are one of the important candidates utilized to reduce the cost of photovoltaic production by minimizing the usage of active materials. However, low light absorption due to low absorption coefficient and/or insufficient active layer thickness can limit the performance of thin film solar cells. Increasing the absorption of light that can be converted into electrical current in thin film solar cells is crucial for enhancing the overall efficiency and in reducing the cost. Therefore, light trapping strategies play a significant role in achieving this goal. The main objectives of light trapping techniques are to decrease incident light reflection, increase the light absorption, and modify the optical response of the device for use in different applications. Nanostructures utilize key sets of approaches to achieve these objectives, including gradual refractive index matching, and coupling incident light into guided modes and localized plasmon resonances, as well as surface plasmon polariton modes. In this review, we discuss some of the recent developments in the design and implementation of nanostructures for light trapping in solar cells. These include the development of solar cells containing photonic and plasmonic nanostructures. The distinct benefits and challenges of these schemes are also explained and discussed. Full article

(This article belongs to the Special Issue Nanostructured Photovoltaic Devices)

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