고효율 적층형 태양전지를 위한 유무기 페로브스카이트

박익재(Ik Jae Park),김동회(Dong Hoe Kim) 한국세라믹학회 2019 세라미스트 Vol.22 No.2

To overcome the theoretical efficiency of single-junction solar cells (> 30 %), tandem solar cells (or multi-junction solar cells) is considered as a strong nominee because of their excellent light utilization. Organic-inorganic halide perovskite has been regarded as a promising candidate material for next-generation tandem solar cell due to not only their excellent optoelectronic properties but also their bandgap-tune-ability and low-temperature processpossibility. As a result, they have been adopted either as a wide-bandgap top cell combined with narrow-bandgap silicon or CuIn x Ga (1-x) Se 2 bottom cells or for all-perovskite tandem solar cells using narrow- and wide-bandgap perovskites. To successfully transition perovskite materials from for single junction to tandem, substantial efforts need to focus on fabricating the high quality wide- and narrow-bandgap perovskite materials and semi-transparent electrode/recombination layer. In this paper, we present an overview of the current research and our outlook regarding perovskite-based tandem solar technology. Several key challenges discussed are: 1) a wide-bandgap perovskite for top-cell in multi-junction tandem solar cells; 2) a narrow-bandgap perovskite for bottom-cell in allperovskite tandem solar cells, and 3) suitable semi-transparent conducting layer for efficient electrode or recombination layer in tandem solar cells.

Surface Coverage Enhancement of a Mixed Halide Perovskite Film by using an UV-Ozone Treatment

이현호,Seunghyun Rhee,Jaeyoul Kim,Changhee Lee,김혁 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.69 No.3

Recently, a significant breakthrough in emerging photovoltaics occurred. Now, perovskite solar cells, hybrid types of organic and inorganic solar cells, are considered as reliable next-generation solar cells due to their outstanding photovoltaic performance. Records of the National Renewable Energy Laboratory (NREL) on cell efficiency research indicates a prominent growth in the power conversion efficiency (PCE) of a perovskite solar cells which is now approaching 20.1%. Perovskite solar cells are, in general, classified into three types based on their structures; the mesoporous type with TiO2 nanoparticles, the meso-superstructure type with Al2O3 and the planar hetero-junction type. Among them, planar-structured perovskite solar cells have strong advantages due to their easy processibility and flexibility. We can replace the materials in the electron transport layer (ETL) and the hole transport layer (HTL) with common materials that are available in organic solar cells. However, a great challenge is to fabricate a high-quality perovskite film because the perovskite morphology is highly sensitive to its fabrication conditions. For control of the film’s morphology, some experiments, such as changing the annealing temperature or time and adding some additives, have been done to increase the surface coverage of perovskite films. In this work, we introduce normal, planar, perovskite solar cells with a hetero-junction structure based on compact TiO2 and a mixed halide perovskite (CH3NH3PbI3−xClx). To enlarge the surface coverage of perovskite film, we used an UV-ozone treatment on top of the compact TiO2, which made the surface of TiO2 hydrophilic. Because a perovskite precursor is hydrophilic, an UV-ozone treatment is expected to improve the wettability between the compact TiO2 and the perovskite film. Here, we present the photovoltaic performance, along with the surface coverage difference, for various UV-ozone treatment time. In addition, the effect of the UV-ozone treatment was examined by using an opto-electronic analysis.

Recent Advances of Flexible Hybrid Perovskite Solar Cells

신동희,허진혁,임상혁 한국물리학회 2017 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.71 No.10

Recently, hybrid perovskite solar cells have attracted great interest because they can be fabricated to low cost, flexible, and highly efficient solar cells. Here, we introduced recent advances of flexible hybrid perovskite solar cells. We introduced research background of flexible perovskite solar cells in introduction part. Then we composed the main body to i) structure and properties of hybrid perovskite solar cells, ii) why flexible hybrid perovskite solar cells are important?, iii) transparent conducting oxide (TCO) based flexible hybrid perovskite solar cells, and iv) TCO-free transparent conducting electrode (TCE) based flexible hybrid perovskite solar cells. Finally, we summarized research outlook of flexible hybrid perovskite solar cells.

페로브스카이트 태양전지에 관한 고찰: 재료 및 장치적 특성

최다영,임세영,김한결 한국태양광발전학회 2023 Current Photovoltaic Research Vol.11 No.1

Tin perovskite solar cells have attracted a lot of attention due to their potential to address the toxicity of lead, which is the biggest barrier to commercialization of perovskite solar cells. Unlike other lead-free perovskite, tin perovskite have a direct bandgap, which is suitable for use as light harvesting, and relatively good stability, which has led to a lot of attention. Since the first tin perovskite solar cell was reported in 2014, it has achieved an impressive power conversion efficiency of 14.81%. However, this efficiency is still low compared to that of lead perovskite solar cells, and the stability of tin perovskite solar cells is also an issue that needs to be addressed. In this review, we will discuss the basic properties of the tin atom in comparison to the lead atom, and then discuss the crystal structure, phase transition, and basic properties of tin perovskite. We will then discuss the advantages, applications, challenges, and strategies of tin perovskite, In particular, we will focus on how to prevent the oxidation of tin, which is arguably the biggest challenge for using tin perovskite solar cells. At the end, we summarize the key factors that need to be addressed for higher efficiency and stability, emphasizing what is needed to commercialize tin perovskite solar cells.

Electron extraction mechanism in low hysteresis perovskite solar cells using single crystal TiO₂ nanorods

Yu, Fangda,Han, Gill Sang,Tu, Yen Jung,Roh, Hee-Suk,Lee, Jung-Kun Elsevier 2018 SOLAR ENERGY -PHOENIX ARIZONA THEN NEW YORK- Vol.167 No.-

<P><B>Abstract</B></P> <P>This study compares the photovoltaic performance of perovskite solar cells PSCs which use different types of TiO<SUB>2</SUB> mesoporous scaffold; nanoparticle (NP) film and nanorod (NR) array. In PSCs of TiO<SUB>2</SUB> NRs, the hysteresis of current density–voltage (<I>J-V</I>) curves is reduced significantly. The hysteresis index of PSCs of 670 nm long NRs is only 0.014. A difference in the charge accumulation at the TiO<SUB>2</SUB>-perovskite interface and the trapping site density is responsible for the smaller hysteresis of PSCs of TiO<SUB>2</SUB> NRs. In PSCs of TiO<SUB>2</SUB> NRs, mobile ions migrate longer and less electrons are trapped on the surface of TiO<SUB>2</SUB> NRs. This leads to a unique columnar space charge polarization at the TiO<SUB>2</SUB>-perovskite interface, which facilitates electron extraction and suppresses the hysteresis of <I>J-V</I> curve. Our study shows a new way to design the microstructure of the mesoporous TiO<SUB>2</SUB> layer for hysteresis-free high performance perovskite solar cells.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Hybrid perovskite solar cells are built on TiO<SUB>2</SUB> single crystals nanorods. </LI> <LI> Nanorod solar cells has smaller hysteresis than nanoparticle solar cells. </LI> <LI> Morphology of the mesoporous TiO<SUB>2</SUB> layer controls electron extraction behavior. </LI> <LI> Selective accumulation of anions explains charge transport in the nanorod. </LI> <LI> Extraction mechanism is a key to low hysteresis of nanorod solar cells. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

페로브스카이트 태양전지 계면 결함이 효율과 온도계수에 미치는 영향

백승재,차명회,이택기 대한전기학회 2022 전기학회논문지 Vol.71 No.12

The perovskite solar cell is a next-generation solar technology that is expected to realize low manufacturing cost and high output. In order to improve the efficiency of perovskite solar cells, research and development to improve the related new material development and interface formation process is being actively carried out worldwide. Among them, it is essential to establish a systematic development plan in the future to establish a theoretical basis for improving solar cell characteristics by improving the interface formation process. In this paper, the effect of the quantified defect density at the solar cell interface on the solar cell characteristics is presented using a simulation technique. It is confirmed that the perovskite-electron-transporting layer interfacial trap has a greater effect on the reduction of solar cell efficiency than the perovskite and the hole-transporting layer interfacial trap, and has a greater effect on the reduction of the temperature coefficient of solar cell efficiency. In the future development of perovskite solar cells, it is judged that the development of a process for controlling defects at the interface between the perovskite and the electron transport layer has the highest importance

Two-terminal mechanical perovskite/silicon tandem solar cells with transparent conductive adhesives

Choi, In Young,Kim, Chan Ul,Park, Wonjin,Lee, Hyungmin,Song, Myoung Hoon,Hong, Kuen Kee,Seok, Sang Il,Choi, Kyoung Jin Elsevier 2019 Nano energy Vol.65 No.-

<P><B>Abstract</B></P> <P>Herein, we demonstrate a novel two-terminal perovskite/silicon mechanical tandem solar cell, fabricated by bonding a silicon cell upside down on a perovskite cell using a transparent conductive adhesive (TCA). The TCA consists of Ag-coated poly(methyl 2-methylpropenoate) microparticles embedded in a polymer adhesive. The Ag microparticles serve as an electrical current path, and the polymer adhesive mechanically bonds two sub-cells. The specific contact resistance and transmittance of the TCA layer were determined to be 5.46 × 10<SUP>−2</SUP> Ω∙cm<SUP>2</SUP> and >97.0%, respectively. Through an optical simulation, the current of the perovskite top cell was predicted to match the current of the p-type Si bottom cell with an Al back-surface field (BSF) layer when the thickness of MAPbI3 was 150 nm. The tandem cell fabricated under the optimal current matching conditions exhibited a current density of 15.43 mA cm-2, an open-circuit voltage of 1.59 V, and a fill factor of 79%, resulting in a steady-state efficiency of 19.4%. To the best of our knowledge, our result is the highest efficiency among two-terminal mechanical perovskite/silicon tandem cells. The unique structure of this tandem cell facilitates an excellent long-term stability without encapsulation in humid environment.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A novel idea to fabricate a two-terminal mechanical tandem solar cell by using a transparent conductive adhesives. </LI> <LI> Transparent conductive adhesives make the commercial textured silicon cells easily be tandemized with perovskite cells. </LI> <LI> Optical simulation for current matching of two sub-cells. </LI> <LI> We propose strategies to achieve a higher efficiency (>24%) through PERC silicon cells and band-gap-tuned perovskite cells. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

TiO₂/RbPbI₃ halide perovskite solar cells

Jung, Mi-Hee,Rhim, Sonny H.,Moon, Dohyun North-Holland 2017 Solar Energy Materials and Solar Cells Vol. No.

<P><B>Abstract</B></P> <P>Inorganic-organic halide perovskites hold the great promise for next-generation photovoltaics due to their excellent high performance and low cost. However, major limitation for the commercialization of perovskite solar cell can be attributed to the transformation and degradation of lead halide perovskite during the exposure of environmental humidity and photon irradiation. To solve these problems, herein, we apply the one-dimensional and inorganic RbPbI<SUB>3</SUB> perovskite into the solar cell because it shows the superior stability in environmental conditions. After RbPbI<SUB>3</SUB> perovskite was applied into the solar cell with a FTO/TiO<SUB>2</SUB>/RbPbI<SUB>3</SUB>/Spiro-MeOTAD/Au configuration, the device exhibits an open circuit voltage of 0.62V, photocurrent density of 3.75mA/cm<SUP>2</SUP>, fill factor of 44.60%, and 1.04% of PCE by reverse sweeping direction. Even though the performance of RbPbI<SUB>3</SUB> device was still lower than other perovskite solar cells, this approach enabled us to establish the key step to make a highly stable perovskite film, leading to the best photovoltaic performance for real applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We applied the RbPbI<SUB>3</SUB> to a solar cell to determine the performance of 1D perovskite. </LI> <LI> RbPbI<SUB>3</SUB> perovskite shows the superior stability for the environmental conditions. </LI> <LI> The band gap alignment of RbPbI<SUB>3</SUB> perovskite is well matched with that of TiO<SUB>2</SUB>. </LI> <LI> The device with RbPbI<SUB>3</SUB> perovskite shows little hysteresis in the <I>J</I>-V scan direction. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>The solar cell was fabricated with one dimensional RbPbI<SUB>3</SUB> perovskite as a light absorber.</P> <P>[DISPLAY OMISSION]</P>

Hexagonal array micro-convex patterned substrate for improving diffused transmittance in perovskite solar cells

Oh, Kyoung Suk,Byun, Minseop,Kim, Minjin,Kim, Yang Doo,Kim, Kwan,Huh, Daihong,Kim, Dong Suk,Lee, Heon Elsevier 2018 THIN SOLID FILMS - Vol.660 No.-

<P><B>Abstract</B></P> <P>In the past decade, the fastest development in solar cell research has occurred for perovskite solar cells. Owing to the favorable properties of perovskite materials, perovskite solar cells exhibit excellent power conversion efficiencies and there appears great potential for future development. In this paper, we report the fabrication of a substrate with excellent optical properties by incorporating hexagonal array micro-convex (HAMC) nanostructures in it before integration with the electrode (indium tin oxide and zinc oxide) and the halide for use in organic-inorganic perovskite solar cells. This was fabricated using nanoimprint lithography which showed excellent throughput and involved simple processing methods. The HAMC nanostructured substrate showed strong light scattering as compared to that of the conventional substrate. This resulted in the increase of current density of the fabricated solar cell from 19.45 mA/cm<SUP>2</SUP> (un-patterned substrate) to 20.92 mA/cm<SUP>2</SUP> (nanostructured substrate) with accompanying increase in the external quantum efficiency and a satisfactory performance by the perovskite solar cell.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Substrate with excellent optical properties for perovskite solar cells was prepared. </LI> <LI> Hexagonal array micro-convex nanostructures were incorporated into the substrate. </LI> <LI> Solar cell shows 20.92 mA/cm<SUP>2</SUP> current density and 14.86% conversion efficiency. </LI> <LI> These values are higher than those of the reference cell by 3% and 5%, respectively. </LI> </UL> </P>

Device design rules and operation principles of high-power perovskite solar cells for indoor applications

Ann, Myung Hyun,Kim, Jincheol,Kim, Moonyong,Alosaimi, Ghaida,Kim, Dohyung,Ha, Na Young,Seidel, Jan,Park, Nochang,Yun, Jae Sung,Kim, Jong H. Elsevier 2020 Nano energy Vol.68 No.-

<P><B>Abstract</B></P> <P>In this work, we report on the design principles of high-power perovskite solar cells (PSCs) for low-intensity indoor light applications, with a particular focus on the electron transport layers (ETLs). It was found that the mechanism of power generation of PSCs under low-intensity LED and halogen lights is surprisingly different compared to the 1 Sun standard test condition (STC). Although a higher power conversion efficiency (PCE) was obtained from the PSC based on mesoporous-TiO<SUB>2</SUB> (m-TiO<SUB>2</SUB>) under STC, compared to the compact-TiO<SUB>2</SUB> (c-TiO<SUB>2</SUB>) PSC, c-TiO<SUB>2</SUB> PSCs generated higher power than m-TiO<SUB>2</SUB> PSCs under low-intensity (200–1600 Lux) conditions. This result indicates that high PCE at STC cannot guarantee a reliable high-power output of PSCs under low-intensity conditions. Based on the systemic characterization of the ideality factor, charge recombination, trap density, and charge-separation, it was revealed that interfacial charge traps or defects at the electron transport layer/perovskite have a critical impact on the resulting power density of PSC under weak light conditions. Based on Suns-<I>V</I> <SUB>OC</SUB> measurements with local ideality factor analyses, it was proved that the trap states cause non-ideal behavior of PSCs under low-intensity light conditions. This is due to the additional trap states that are present at the m-TiO<SUB>2</SUB>/perovskite interface, as confirmed by trap-density measurements. Based on Kelvin probe force microscopy (KPFM) measurements, it was confirmed that these traps prohibit efficient charge separation at the perovskite grain boundaries when the light intensity is weak. According to these observations, it is suggested that for the fabrication of high-power PSCs under low-intensity indoor light, the interface trap density should be lower than the excess carrier density to fill the traps at the perovskite's grain boundaries. Finally, using the suggested principle, we succeeded in demonstrating high-performance PSCs by employing an organic ETL, yielding maximum power densities up to 12.36 (56.43), 28.03 (100.97), 63.79 (187.67), and 147.74 (376.85) <I>μ</I>W/cm<SUP>2</SUP> under 200, 400, 800, and 1600 Lux LED (halogen) illumination which are among the highest values for indoor low-intensity-light solar cells.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The device design principles of high-power perovskite solar cells for indoor light applications were investigated. </LI> <LI> For high-power under indoor light, trap density should be lower than excess carrier density. </LI> <LI> Perovskite solar cells with high-power density up to 376.85 <I>μ</I>W/cm2 under indoor light were demonstrated. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>In this work, the device design rules for achieving high-power perovskite solar cells under indoor light are suggested based on the device operation principle under low intensity light conditions.</P> <P>[DISPLAY OMISSION]</P>