scholarly journals A Facile Microwave-Assisted Hydrothermal Synthesis of Graphene Quantum Dots for Organic Solar Cell Efficiency Improvement

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Thi Thu Hoang ◽  
Hoai Phuong Pham ◽  
Quang Trung Tran

Carbon-based nanomaterials have successively remained at the forefront of different research fields and applications for years. Understanding of low-dimension carbon material family (CNT, fullerenes, graphene, and graphene quantum dots) has arrived at a certain extension. In this report, graphene quantum dots were synthesized from graphene oxide with a microwave-assisted hydrothermal method. Compared with conventional time-consuming hydrothermal routes, this novel method requires a much shorter time, around ten minutes. Successful formation of quantum dots derived from graphene sheets was verified with microscopic and spectroscopic characterization. Nanoparticles present a diameter of about 2-8 nm, blue emission under ultraviolet excitation, and good dispersion in polar solvents and can be collected in powder form. The synthesized graphene quantum dots were utilized as a hole transport layer in organic solar cells to enhance the cell quantum efficiency. Such quantum dots possess energy levels (Ec and Ev) relevant to HOMO and LUMO levels of conductive polymers. Mixing P3HT:PCBM polymer and graphene quantum dots of sufficient extent notably helps reduce potential difference at interfaces of the two materials. Overall efficiency consequently advances to 1.43%, an increase of more than 44% compared with pristine cells (0.99%).

2013 ◽  
Vol 15 (43) ◽  
pp. 18973 ◽  
Author(s):  
Miaomiao Li ◽  
Wang Ni ◽  
Bin Kan ◽  
Xiangjian Wan ◽  
Long Zhang ◽  
...  

2021 ◽  
Vol 8 (3) ◽  
Author(s):  
Kulrisa Kuntamung ◽  
Patrawadee Yaiwong ◽  
Chutiparn Lertvachirapaiboon ◽  
Ryousuke Ishikawa ◽  
Kazunari Shinbo ◽  
...  

We studied the effect of gold quantum dots (AuQDs)/grating-coupled surface plasmon resonance (GC-SPR) in inverted organic solar cells (OSCs). AuQDs are located within a GC-SPR evanescent field in inverted OSCs, indicating an interaction between GC-SPR and AuQDs' quantum effects, subsequently giving rise to improvement in the performance of inverted OSCs. The fabricated solar cell device comprises an ITO/TiO 2 /P3HT : PCBM/PEDOT : PSS : AuQD/silver grating structure. The AuQDs were loaded into a hole transport layer (PEDOT : PSS) of the inverted OSCs to increase absorption in the near-ultraviolet (UV) light region and to emit visible light into the neighbouring photoactive layer, thereby achieving light-harvesting improvement of the device. The grating structures were fabricated on P3HT:PCBM layers using a nanoimprinting technique to induce GC-SPR within the inverted OSCs. The AuQDs incorporated within the strongly enhanced GC-SPR evanescent electric field on metallic nanostructures in the inverted OSCs improved the short-circuit current and the efficiency of photovoltaic devices. In comparison with the reference OSC and OSCs with only green AuQDs or only metallic grating, the developed device indicates enhancement of up to 16% power conversion efficiency. This indicates that our light management approach allows for greater light utilization of the OSCs because of the synergistic effect of G-AuQDs and GC-SPR.


Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1464
Author(s):  
Kwang Hyun Park ◽  
Sunggyeong Jung ◽  
Jungmo Kim ◽  
Byoung-Min Ko ◽  
Wang-Geun Shim ◽  
...  

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.


2017 ◽  
Vol 9 (9) ◽  
pp. 1616-1625 ◽  
Author(s):  
Amirhossein Hasani ◽  
Jaber Nasrollah Gavgani ◽  
Reza Mohammadi Pashaki ◽  
Siamak Baseghi ◽  
Alireza Salehi ◽  
...  

2019 ◽  
Vol 2 (5) ◽  
pp. 113-121
Author(s):  
Thu Thi Hoang ◽  
Hoa Tran My Huynh ◽  
Phuong Hoai Pham ◽  
Hung Hoang Nguyen ◽  
Giang Thuy Thanh Le ◽  
...  

In this report, we studied and fabricated graphene quantum dots by improved the Hummer method using NH3 reducing agent. The diameter of graphene quantum dots was approximately 6 nm, applied as the hole transport layer in organic solar cell to improve the quantum efficiency of solar cells. GQDs were very friendly with environment, made at low temperatures and might be dried into powder form and dissolved well in polar solvents. Graphene quantum dots with a 0D structure had the workfunction suistable for the conductive polymer which increased the short current (from 2.41 mA/cm2 to 4.38 mA/cm2) of polymer solar cells. They improved the performance significantly compared to conventional solar cells.


2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Nguyen Nang Dinh ◽  
Do Ngoc Chung ◽  
Tran Thi Thao ◽  
David Hui

Polymeric nanocomposite films from PEDOT and MEH-PPV embedded with surface modified TiO2nanoparticles for the hole transport layer and emission layer were prepared, respectively, for organic emitting diodes (OLEDs). The composite of MEH-PPV+nc-TiO2was used for organic solar cells (OSCs). The characterization of these nanocomposites and devices showed that electrical (I-Vcharacteristics) and spectroscopic (photoluminescent) properties of conjugate polymers were enhanced by the incorporation of nc-TiO2in the polymers. The organic light emitting diodes made from the nanocomposite films would exhibit a larger photonic efficiency and a longer lasting life. For the organic solar cells made from MEH-PPV+nc-TiO2composite, a fill factor reached a value of about 0.34. Under illumination by light with a power density of 50 mW/cm2, the photoelectrical conversion efficiency was about 0.15% corresponding to an open circuit voltageVoc= 0.126 V and a shortcut circuit current densityJsc= 1.18 mA/cm2.


2012 ◽  
Vol 9 (5) ◽  
pp. 399-406
Author(s):  
Do Chung ◽  
Nguyen Dinh ◽  
Tran Thao ◽  
Nguyen Nam ◽  
Tran Trung ◽  
...  

Polymeric nanocomposite films from PEDOT and MEH-PPV embedded with surface modified TiO2 nanoparticles were prepared, respectively for the hole transport layer (HTL) and emission layer (EL) in Organic Light Emitting Diodes (OLED). The composite of MEH-PPV + nc-TiO2 was used for Organic Solar Cells (OCS). The results from the characterization of the properties of the nanocomposites and devices showed that electrical (I-V characteristics) and spectroscopic (photoluminescent) properties of the conjugate polymers were enhanced due to the incorporation of nc-TiO2 in the polymers. The OLEDs made from the nanocomposite films would exhibit a larger photonic efficiency and a longer lasting life. For the OSC made from MEH-PPV + nc-TiO2 composite, the fill factor (FF) reached a value as high as 0.34. Under illumination of light with a power density of 50 mW/cm2, the photoelectrical conversion efficiency (PEC) was found to be of 0.15% corresponding to an open circuit voltage VOC = 1.15 V and a short-cut circuit current density JSC = 0.125 mA/cm2.


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