Theoretical study on mesoscopic-size impurity effects in the charge separation process of organic photocells

2018 ◽  
Vol 20 (21) ◽  
pp. 14846-14854
Author(s):  
Tomomi Shimazaki ◽  
Motomichi Tashiro ◽  
Takahito Nakajima
Keyword(s):  
Charge Separation ◽  
High Performance ◽  
Theoretical Study ◽  
Bulk Heterojunction ◽  
Separation Process ◽  
Impurity Effects ◽  
Heterojunction Structure ◽  
Donor And Acceptor

A bulk-heterojunction structure is often employed to develop high-performance organic photocells, in which the donor and acceptor regions are complexly intertwined.

Nanometer-Scaled Landscape of Polymer:Fullerene Blends Mapped with Visible s-SNOM

2021 ◽  
Author(s):  
Ya-Rong Lee ◽  
Cheng-Chia Huang ◽  
Wen-Yu Huang ◽  
Chin-Ti Chen ◽  
Ping-Tsung Huang ◽  
...  
Keyword(s):  
Active Layer ◽  
Organic Solar Cells ◽  
Charge Separation ◽  
High Performance ◽  
Bulk Heterojunction ◽  
Near Field ◽  
Photovoltaic Performance ◽  
Energy Landscapes ◽  
Donor And Acceptor ◽  
Shed Light

Abstract Bulk heterojunction is one key concept leading to breakthrough in organic photovoltaics. The active layer is expectantly formed of distinct morphologies that carry out their respective roles in photovoltaic performance. The morphology-performance relationship however remains stymied, because unequivocal morphology at the nanoscale is not available. We used scattering-type scanning near-field optical microscopy operating with a visible light source (visible s-SNOM) to disclose the nanomorphology of P3HT:PCBM and pBCN:PCBM blends. Donor and acceptor domain as well as intermixed phase were identified and their intertwined distributions were mapped. We proposed energy landscapes of the BHJ active layer to shed light on the roles played by these morphologies in charge separation, transport and recombination. This study shows that visible s-SNOM is capable of profiling the morphological backdrop pertaining to the operation of high performance organic solar cells.

scholarly journals Preparation of Cu3N/MoS2 Heterojunction through Magnetron Sputtering and Investigation of Its Structure and Optical Performance

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1873
Author(s):  
Liwen Zhu ◽  
Xiu Cao ◽  
Chenyang Gong ◽  
Aihua Jiang ◽  
Yong Cheng ◽  
...  
Keyword(s):  
Magnetron Sputtering ◽  
Band Gap ◽  
Transmission Spectrum ◽  
Charge Separation ◽  
Potential Application ◽  
High Performance ◽  
Optical Band Gap ◽  
Type Ii ◽  
Optical Performance ◽  
Heterojunction Structure

Cu3N/MoS2 heterojunction was prepared through magnetron sputtering, and its optical band gap was investigated. Results showed that the prepared Cu3N/MoS2 heterojunction had a clear surface heterojunction structure, uniform surface grains, and no evident cracks. The optical band gap (1.98 eV) of Cu3N/MoS2 heterojunction was obtained by analyzing the ultraviolet-visible transmission spectrum. The valence and conduction band offsets of Cu3N/MoS2 heterojunction were 1.42 and 0.82 eV, respectively. The Cu3N film and multilayer MoS2 formed a type-II heterojunction. After the two materials adhered to form the heterojunction, the interface electrons flowed from MoS2 to Cu3N because the latter had higher Fermi level than the former. This behavior caused the formation of additional electrons in the Cu3N and MoS2 layers and the change in optical band gap, which was conducive to the charge separation of electrons in MoS2 or MoS2 holes. The prepared Cu3N/MoS2 heterojunction has potential application in various high-performance photoelectric devices, such as photocatalysts and photodetectors.

scholarly journals Selective Extraction of Nonfullerene Acceptors from Bulk-Heterojunction Layer in Organic Solar Cells for Detailed Analysis of Microstructure

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2107
Author(s):  
Masahiro Nakano ◽  
Akira Takahara ◽  
Kenji Genda ◽  
Md. Shahiduzzaman ◽  
Makoto Karakawa ◽  
...  
Keyword(s):  
Solar Cells ◽  
Detailed Analysis ◽  
Organic Solar Cells ◽  
High Performance ◽  
Bulk Heterojunction ◽  
Glycidyl Ether ◽  
Complex Mixture ◽  
Selective Extraction ◽  
Donor And Acceptor ◽  
Butyl Glycidyl Ether

Detailed analyses of the microstructures of bulk-heterojunction (BHJ) layers are important for the development of high-performance photovoltaic organic solar cells (OSCs). However, analytical methods for BHJ layer microstructures are limited because BHJ films are composed of a complex mixture of donor and acceptor materials. In our previous study on the microstructure of a BHJ film composed of donor polymers and fullerene-based acceptors, we analyzed donor polymer-only films after selectively extracting fullerene-based acceptors from the film by atomic force microscopy (AFM). Not only was AFM suitable for a clear analysis of the morphology of the donor polymers in the BHJ film, but it also allowed us to approximate the acceptor morphology by analyzing the pores in the extracted films. Herein we report a method for the selective extraction of nonfullerene acceptors (NFAs) from a BHJ layer in OSCs and provide a detailed analysis of the remaining BHJ films based upon AFM. We found that butyl glycidyl ether is an effective solvent to extract NFAs from BHJ films without damaging the donor polymer films. By using the selective extraction method, the morphologies of NFA-free BHJ films fabricated under various conditions were studied in detail. The results may be useful for the optimization of BHJ film structures composed of NFAs and donor polymers.

Self-assembled bulk heterojunctions from integral molecules with nonconjugately linked donor and acceptor units for photovoltaic applications

2020 ◽  
Vol 4 (7) ◽  
pp. 3190-3210
Author(s):  
Hao Liu ◽  
Huaizhi Gao ◽  
Jun Lin ◽  
Tasawar Hayat ◽  
Ahmed Alsaedi ◽  
...  
Keyword(s):  
Solar Cells ◽  
Bulk Heterojunction ◽  
Polymer Solar Cells ◽  
Bulk Heterojunctions ◽  
Heterojunction Structure ◽  
Highly Efficient ◽  
Donor And Acceptor ◽  
Photovoltaic Applications ◽  
Donor Acceptor ◽  
Self Assembled

Donor–acceptor integral molecules with donor and acceptor units interlinked by nonconjugated flexible linking units can self-assemble into an ideal bulk heterojunction structure for application in highly efficient polymer solar cells are reviewed.

High-performance Nonvolatile Organic Photoelectronic Transistor Memory Based on Bulk Heterojunction Structure

2020 ◽  
Vol 12 (28) ◽  
pp. 31716-31724 ◽  
Author(s):  
Shuqiong Lan ◽  
Jianfeng Zhong ◽  
Enlong Li ◽  
Yujie Yan ◽  
Xiaomin Wu ◽  
...  
Keyword(s):  
High Performance ◽  
Bulk Heterojunction ◽  
Heterojunction Structure

Constructing bulk defective perovskite SrTiO3 nanocubes for high performance photocatalysts

Nanoscale ◽  
2016 ◽  
Vol 8 (38) ◽  
pp. 16963-16968 ◽  
Author(s):  
Guoqiang Zhang ◽  
Wenshuai Jiang ◽  
Shixin Hua ◽  
Haifeng Zhao ◽  
Ligong Zhang ◽  
...  
Keyword(s):  
Charge Separation ◽  
High Performance ◽  
Oxygen Vacancies ◽  
Separation Process

Defects (Ti3+ or oxygen vacancies) have been demonstrated to promote the charge separation process in SrTiO3 based photocatalysts.

Nanoscale phase separation in the bulk heterojunction structure of perylene bisimide and porphyrin by controlling intermolecular interactions

RSC Advances ◽  
2014 ◽  
Vol 4 (66) ◽  
pp. 35072-35076 ◽  
Author(s):  
Yunan Zhang ◽  
Wenqiang Zhang ◽  
Li Nian ◽  
Yuyu Pan ◽  
Zengqi Xie ◽  
...  
Keyword(s):  
Phase Separation ◽  
Intermolecular Interactions ◽  
Bulk Heterojunction ◽  
Heterojunction Structure ◽  
Perylene Bisimide ◽  
Nanoscale Phase Separation ◽  
Donor And Acceptor

Phase separation has been achieved through designing directional intermolecular interactions of donor and acceptor materials in bulk heterojunction structures.

scholarly journals Carbon Nanodots as a Potential Transport Layer for Boosting Performance of All-Inorganic Perovskite Nanocrystals-based Photodetector

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 717
Author(s):  
Hassan Algadi ◽  
Ahmad Umar ◽  
Hasan Albargi ◽  
Turki Alsuwian ◽  
Sotirios Baskoutas
Keyword(s):  
Charge Separation ◽  
High Performance ◽  
Band Alignment ◽  
Transport Layer ◽  
Carbon Nanodots ◽  
Separation Mechanism ◽  
Perovskite Layer ◽  
Inorganic Perovskite ◽  
Highly Efficient ◽  
Efficient Charge

A low-cost and simple drop-casting method was used to fabricate a carbon nanodot (C-dot)/all-inorganic perovskite (CsPbBr3) nanosheet bilayer heterojunction photodetector on a SiO2/Si substrate. The C-dot/perovskite bilayer heterojunction photodetector shows a high performance with a responsivity (R) of 1.09 A/W, almost five times higher than that of a CsPbBr3-based photodetector (0.21 A/W). In addition, the hybrid photodetector exhibits a fast response speed of 1.318/1.342 µs and a highly stable photocurrent of 6.97 µA at 10 V bias voltage. These figures of merits are comparable with, or much better than, most reported perovskite heterojunction photodetectors. UV–Vis absorption and photoluminescent spectra measurements reveal that the C-dot/perovskite bilayer heterojunction has a band gap similar to the pure perovskite layer, confirming that the absorption and emission in the bilayer heterojunction is dominated by the top layer of the perovskite. Moreover, the emission intensity of the C-dot/perovskite bilayer heterojunction is less than that of the pure perovskite layer, indicating that a significant number of charges were extracted by the C-dot layer. The studied band alignment of the C-dots and perovskites in the dark and under emission reveals that the photodetector has a highly efficient charge separation mechanism at the C-dot/perovskite interface, where the recombination rate between photogenerated electrons and holes is significantly reduced. This highly efficient charge separation mechanism is the main reason behind the enhanced performance of the C-dot/perovskite bilayer heterojunction photodetector.

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