Dye-Sensitized Tandem Solar Cells with Extremely High Open-Circuit Voltage Using Co(II)/Co(III) Electrolyte

Choi, Won Seok,Choi, In Taek,You, Ban Seok,Yang, Ji-Woon,Ju, Myung Jong,Kim, Hwan Kyu LASER PAGES PUBLISHING LTD 2015 ISRAEL JOURNAL OF CHEMISTRY Vol.55 No.9

<P> For achieving a high open-circuit voltage (V<SUB>oc</SUB>) in dye-sensitized tandem solar cells, series-connected tandem solar cells were fabricated. In order to optimize series-connected tandem solar cell systems, the current density of the top and bottom cells should be well matched to be identical, and the V<SUB>oc</SUB> of each of the cells should also be as high as possible. Furthermore, the top cell should be transparent and the bottom cell should have the longer-wavelength absorption, for utilizing only the light passing through the top cell. This leads to a high V<SUB>oc</SUB>. In this study, we report dye-sensitized tandem solar cells having an extremely high V<SUB>oc</SUB> using the Co(bpy)<SUB>3</SUB><SUP>2+/3+</SUP> (bpy=2,2′-bipyridine) redox couple. Dye-sensitized tandem solar cells employing JK303/HC-A1 with the Co(bpy)<SUB>3</SUB><SUP>2+/3+</SUP> redox couple as the top cell and N749/HC-A4 with the I-/I<SUB>3</SUB>- redox couple as the bottom cell were shown to have an extremely high V<SUB>oc</SUB> of >1.66V, the highest value for dye-sensitized tandem solar cells reported to date. </P>

염료감응 태양전지

박남규 한국공업화학회 2004 공업화학 Vol.15 No.3

빛에너지를 전기에너지로 직접 변환 시키는 태양전지는 구성하는 물질에 따라 무기물 태양전지와 유기물 태양전지로 나눌 수 있다. 무기물 태양전지는 실리콘, 화합반도체 등의 소재가 pn 접합으로 구성되어 있으며, 유기물 태양전지는 염료분자가 나노결정 입자 표면에 흡착되어 있는 것을 특징으로 하는 염료감응형과 donor-acceptor 특성의 유기(고)분자형으로 나눌 수 있다. 특히 염료감응형 유기태양전지는 높은 에너지변환 효율(약 11%)과 매우 낮은 제조가격 때문에 차세대 태양전지로 각광받고 있다. 본 총설에서는 염료감응 태양전지의 구조 및 작동원리를 설명하고, 최근의 연구개발 및 산업동향을 소개하였다. Solar cells, converting directly light into electricity, can be categorized by materials comprising solar cells: inorganic-type and organic-type solar cells. Inorganic solar cells are composed of inorganic n-type and p-type materials such as silicon and compound semiconductors, where the structure of inorganic solar cell is typically built by pn junction. For the organic solar cells, there are two types: dye-sensitized solar cell and organic donor-acceptor solar cell. Dye-sensitized solar cell, consisting of nanocrystalline oxide film sensitized with dye molecule, redox electrolyte and metal counter electrode, is consideed as alternative to conventional solar cells due to its high solar-to-electricity conversiton efficiency (ca. 11%) and low cost. In this article, the structure, the operation principle and the recent R&D and industrial trends of dye-sensitized solar cells are discussed.

Enhanced Performance of Dye Co-sensitized Solar Cells by Panchromatic Light Harvesting

김영록,Hyun Sik Yang,안광순,김재홍,한윤수 한국물리학회 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.64 No.6

The Photovoltaic properties of dye co-sensitized solar cells fabricated by using a onebathmixed dye solution were compared with those of mono-sensitized devices. Co-sensitizedTiO2 photo-electrodes were prepared from a mixed dye solution of M-Red [2-cyano-3(10-hexthyl-phenothiazin)acrylic acid] or D-Red [3,3’-hexyl-bis(phenothiazine-2-cyanoacrylic acid)]and S-Blue [(5-carboxy-3,3-dimethyl-1-nonyl-indolium)methylene-2-(E)-(5-carboxy-3,3-dimethyl-1-octylindolin-2-ylidene)-3-oxocyclobut-1-enolate)] to improve the short-circuit current (Jsc) of dyesensitizedsolar cells (DSSCs). When the photo-electrode was co-sensitized from the mixed solutionof M-Red (75%) and S-Blue (25%), the power conversion efficiency (PCE) of the resulting DSSCsexhibited an 11.2% increase, compared to that of M-Red dye (100%). Use of the mixed dye solutionof M-red and S-Blue is thought to have ability to reduce the aggregation of S-Blue dye adsorbedon TiO2 surface, leading to an enhancement in Jsc of the co-sensitized solar cells. In the case ofD-Red dye, the co-sensitized device prepared from the mixed solution of D-Red (50%) and S-Blue(50%) dye showed a 31.7% enhancement in the PCE, compared to that of the solar cell with a mono(D-Red)-sensitized photo-electrode. Unlike the co-sensitization system using the mixed solution ofM-Red and S-Blue, the optimum photovoltaic performance was found from the mixed solution witha 1:1 ratio (D-Red:S-Blue). This could be attributed to the adsorption rate of D-Red (dimeric red)being faster than that of M-Red (monomeric red) dye, there inducing similar adsorption rates forthe D-Red and the S-blue dye in the one-bath adsorption process for co-sensitization.

은 나노 입자를 이용한 염료감응형 태양전지의 효율 향상 효과

정행윤,홍경진 한국전기전자재료학회 2018 전기전자재료학회논문지 Vol.31 No.1

In this study, e-beam equipment was used to form silver nanoparticles on thin films of TiO2 to increase theefficiency of dye-sensitized solar cells and improve the annealing process. TiO2 thin films with nanoparticlephotoelectrodes were fabricated in individual units for use in dye-sensitized solar cells. The characteristics ofdye-sensitized solar cells were compared to those of the prepared TiO2 photoelectrode with and without nanoparticles. The dye-sensitized solar cells with silver nanoparticles showed a significant increase in the electric current densitycompared with the pure TiO2 dye-sensitized solar cell and improved the solar conversion efficiency to 27.89%. Theincreased density of electric current increased the extent of light absorption of the dye owing to the plasmon resonanceof the nanoparticles at the local surfaces. This phenomenon led to increased light scattering, which in turn increased thecurrent density of the dye-sensitized solar cells and improved the solar conversion efficiency. 본 연구에서는 염료감응형 태양전지의 광전변환효율을 증가시키기 위해 TiO2 박막 위에 은 나노 입자를 형성하고자 E-beam 장비를 이용하였고, 어닐링 공정을 진행하였다. 은 나노 입자들이 형성된 TiO2 박막을 광전극으로 사용하였으며 염료감응형 태양전지 단위 셀을 제작하였다. 은 나노 입자들이 포함 된 TiO2 광전극과 순수한 TiO2 광전극을 사용한 염료감응형 태양전지를 비교하여 특성을 분석하였다. 은 나노 입자들이 포함 된 염료감응형 태양전지는 순수한 TiO2 염료감응형 태양전지에 비해 전류 밀도의 상당한 증가를 가져왔으며 광전변환효율이 최대 27.89% 개선되는 것으로 나타났다. 전류 밀도의 증가는 은 나노 입자들의 국소적 표면 플라즈몬 공명으로 인한 염료의 광흡수를 증가시켜 광 산란의 강화로 인해 염료감응형 태양전지의 전류밀도와 광전변환효율을 증가시켰다.

Co-sensitization of metal free organic dyes in flexible dye sensitized solar cells

Lee, Horim,Kim, Jihun,Kim, Dong Young,Seo, Yongsok Elsevier 2018 ORGANIC ELECTRONICS Vol.52 No.-

<P><B>Abstract</B></P> <P>A metal-free organic dye (JH-1) and an unsymmetrical squaraine dye (SQ2) were used for co-sensitization of a flexible TiO<SUB>2</SUB> electrode in order to obtain a broad spectral response in the visible light regions. Because of enhanced light absorption, the performance of the flexible plastic dye-sensitized solar cells (DSSCs) was enhanced. The dye concentration of co-sensitized TiO<SUB>2</SUB> film was higher than that of individual dye-sensitized TiO<SUB>2</SUB> film, leading to improved photovoltaic performance with the panchromatic light harvesting of JH-1 and SQ2 (350–720 nm). Optimum molar ratio of individual dye, dye concentration and adsorption kinetics onto the TiO<SUB>2</SUB> photoelectrode, and ideal thickness of HS-TiO<SUB>2</SUB> layer have been investigated. A flexible DSSC co-sensitized with the molar ratio of 60:40 (JH-1:SQ2) and TiO<SUB>2</SUB> film thickness of 6 μm yielded a high photocurrent density of 12.32 mA cm<SUP>−2</SUP>, an open circuit voltage of 0.754 V, a fill factor of 0.68, and a power conversion efficiency of 6.31% under 1 sun illumination (100 mW cm<SUP>−2</SUP>). Interestingly, the co-sensitizers did not compete with each other for the absorption. Both the open circuit photovoltage and the photocurrent density were unexpectedly increased with co-sensitization which means that enhancement in photocurrents can be achieved without sacrificing the open circuit photovoltage for the co-sensitized solar cells, once the electron recombination and dye aggregation are retarded by the co-sensitization.</P> <P><B>Highlights</B></P> <P> <UL> <LI> An organic dye (JH-1) and a squaraine dye (SQ2) were used for co-sensitization of a flexible TiO2 electrode. </LI> <LI> Because of enhanced light absorption, the performance of the flexible DSSCs was enhanced. </LI> <LI> A DSSC with a molar ratio of 60:40 (JH-1:SQ2) yielded a power conversion efficiency of 6.31%. </LI> <LI> Both V<SUB>OC</SUB> and J<SUB>SC</SUB> were unexpectedly increased with co-sensitization. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Effects of introducing functional groups on the performance of phenoxazine-based dye-sensitized solar cells

Bae, Jong Hyuk,Lim, Seung Ju,Choi, Jun,Yuk, Sim Bum,Namgoong, Jin Woong,Ko, Jae Hoon,Lee, Woosung,Kim, Jae Pil Elsevier 2019 Dyes and pigments Vol.162 No.-

<P><B>Abstract</B></P> <P>Phenoxazine dyes with a hexyloxy chain and furan moiety were synthesized and used in dye-sensitized solar cells. The dyes were designed to investigate the effects of these substituents on the photophysical and electrochemical properties of the dyes and on cell photovoltaic performance. The introduced hexyloxy moiety, as an additional donor, improved the short-circuit current and open-circuit voltage of the cell by increasing light absorption and steric hindrance, respectively. The furan moiety introduced in the phenoxazine dye as a bridge unit led to a bathochromic shift of the absorption band and a large amount of dye adsorption, increasing the short-circuit current of the cell. Among the synthesized dyes, those with the furan moiety showed the best conversion efficiency of 6.34%.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Effects on the cell performance by hexyloxy and furan group introduced on the phenoxazine dye. </LI> <LI> Increase of open-circuit voltage current by suppressing charge recombination. </LI> <LI> Increase of short-circuit current by bathochromic shift and a large amount of dye adsorption. </LI> <LI> The best efficiency was shown by a cell based on the dye with a furan unit. </LI> </UL> </P>

Dye-Sensitized Metal Oxide Nanostructures and Their Photoelectrochemical Properties

박남규 한국전기화학회 2010 한국전기화학회지 Vol.13 No.1

Nanostructured metal oxides have been widely used in the research fields of photoelectrochemistry,photochemistry and opto-electronics. Dye-sensitized solar cell is a typical example because it is based on nanostructured TiO2. Since the discovery of dye-sensitized solar cell in 1991,it has been considered as a promising photovoltaic solar cell because of low-cost, colorful and semitransparent characteristics. Unlike p-n junction type solar cell, dye-sensitized solar cell is photoelectrochemical type and is usually composed of the dye-adsorbed nanocrystalline metal oxide, the iodide/tri-iodide redox electrolyte and the Pt and/or carbon counter electrode. Among the studied issues to improve efficiency of dye-sensitized solar cell, nanoengineering technologies of metal oxide particle and film have been reviewed in terms of improving optical property, electron transport and electron life time.

Review of the Development of Dyes for Dye-Sensitized Solar Cells

남상훈,부진효,Kyu Hwan Lee,유정훈 한국진공학회 2019 Applied Science and Convergence Technology Vol.28 No.6

Dye-sensitized solar cells (DSSCs) have attracted considerable attention over the last 25 years owing to their potential for the low-cost conversion of photovoltaic energy. The most important DSSC component is the sensitizer dye, which is largely responsible for light harvesting and charge separation. Although tremendous research efforts have been focused on dye development, many challenges remain and a deeper understanding of the design rules for DSSC sensitizers is required to obtain efficient and long-term stable DSSCs. State-of-the-art DSSCs based on single sensitizers have reached power conversion efficiencies (PCEs) of >11.5 % for ruthenium dyes, >13 % for porphyrin dyes, and >14 % for metal-free organic dyes. However, the highest efficiency officially recognized by the National Renewable Energy Laboratory is only 11.9 %, achieved by the Sharp Co., Japan, in 2013. Furthermore, there has been a lack of significant milestones in active commercialization, particularly with respect to exploiting the near-infrared region for higher PCEs and greater device durability. While ruthenium-based dyes have some disadvantages for practical application in DSSCs, both porphyrin and metal-free organic dyes have attracted considerable interest. In this review, we summarize recent progress in the rational design of ruthenium dyes, porphyrin dyes, metal-free organic dyes, and natural dyes for use in DSSCs.

2P-407 Structural optimization of All Solid State Dye Sensitized Solar Cells

김동우,전소연,( Ho Phuong ),( Rajesh Cheruku ),안광순,김재홍 한국공업화학회 2017 한국공업화학회 연구논문 초록집 Vol.2017 No.1

Dye-sensitized solar cells (DSSCs) have been investigated extensively because of their high energy conversion efficiency, low cost and simple fabrication process. However, the liquid electrolyte based DSSC have many problems such as leakage of liquid electrolyte, corrosion of Pt counter and dye degradation which can limit the long-term stability of DSSCs. For such reasons, the all solid-state dye sensitized solar cells (SDSCs) have been attracting much attention for decades. In this study, we fabricated SDSCs using organic dyes that was designed and synthesized as sensitizer for SDSC. All solid-state solar cells were prepared with different structure of organic dyes and their photovoltaic properties were investigated and compared with that of liquid type of DSSCs.

2SK-2 Molecular Tuning of D-π-A Organic Dyes for High Efficiency Dye-Sensitized Solar Cells

( Vinich Promarak ) 한국공업화학회 2017 한국공업화학회 연구논문 초록집 Vol.2017 No.1

Dye-sensitized solar cell (DSSC) has emerged as one of the most attractive photovoltaic devices because it offers the possibility of low-cost conversion of photoenergy. Ruthenium complex and porphyrin dyes are currently the most efficient dyes. These dyes, however, are costly and hard to prepare in high yields, which have led to the evolution of metal-free organic dyes. Organic dyes exhibit not only higher extinction coefficient, but simple preparation, structure modification and purification procedure with a low cost. In this talk, an improvement of the performance of the organic dyes as sensitizers for DSSC by fine tuning the dye chemical structures will be presented. A series of organic dipolar compounds with different molecular configurations of D-D-π-A, D(dendron)-π-A, D-π-A-π-A, D-π (D)-A, D-π-A-π(D)-A bearing triarylamine, carbazole and carbazole dendrons as donor moiety were designed, synthesized and investigated. The relationships between structure of these dyes and properties and cell performances will be drawn and discussed. The choice of π-linker, auxiliary acceptor and terminal acceptor are found to be crucial in designing of the dye. Some of these dyes show power conversion efficiencies surpass that of the Ru-based device measured under similar conditions, indicating a high potential candidate for a commercial use.