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.

Parallel polymer tandem solar cells containing comb-shaped common electrodes

Han, Hee Yoon,Yoon, Hongkee,Yoon, Choon Sup Elsevier 2015 Solar Energy Materials and Solar Cells Vol.132 No.-

<P><B>Abstract</B></P> <P>The poor optical transmittance of common electrodes based on thin metal films in three-terminal parallel tandem solar cells poses a major hindrance to attaining high power conversion efficiency (PCE). High optical transmittance and electrical conductivity of the common electrodes are crucial to achieving high PCE. We report a parallel polymer tandem solar cell that contains a comb-shaped electrode (CSE) based on gold (Au), which provides both high optical transmittance and low electrical resistance. We studied the performance of the tandem cell devices as a function of number of teeth <I>N</I> of the CSEs with tooth dimensions of 50μm (width)×30nm (thickness)×3mm (length). A maximum PCE of 3.72%, which amounts to 85% of the PCE of an ideal tandem cell, was obtained with <I>N</I>=5 in the tandem structure ITO/ZnO/P3HT:PC<SUB>71</SUB>BM/PEDOT:PSS+Triton X-100/Au CSE/PEDOT:PSS/PTB7:PC<SUB>71</SUB>BM/LiF/Al, where ITO is indium tin oxide, P3HT is regio-regular poly(3-hexylthiophene), PC<SUB>71</SUB>BM is [6,6]-phenyl-C71-butyric acid methyl ester, PEDOT:PSS is poly(3,4-ethylenedioxythiophene):poly(styrene sulfonic acid), Triton X-100 is 4-(1,1,3,3-tetramethylbutyl)phenyl-polyethylene glycol, and PTB7 is thieno[3,4-<I>b</I>]-thiophene/benzodithiophene. The combination of high optical transmittance and low electrical resistance of the Au CSE and the conductivity-enhanced hole transport layer of PEDOT:PSS+Triton X-100 resulted in a 20% higher PCE than that obtained using conventional common electrodes based on 12nm thick Au films. We analyzed the resistance of the combined anode, which consists of the Au CSE and the PEDOT:PSS+Triton X-100 film, theoretically. The theoretical results enabled us to predict the optimum number of teeth required for the Au CSEs to give the maximum PCE in three-terminal parallel tandem cells, and showed excellent agreement with the experimental results.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We propose a comb-shaped common electrode (CSE) for parallel tandem solar cells. </LI> <LI> The CSE provides both high optical transmittance and low electrical resistance. </LI> <LI> We studied the performance of the tandem solar cell devices containing the CSEs. </LI> <LI> The use of the gold CSE leads to the increase in power conversion efficiency by 20%. </LI> <LI> Our theoretical analysis enabled us to predict the optimum number of CSE teeth. </LI> </UL> </P>

Latest developments in CdTe, CuInGaSe2 and GaAs/AlGaAs thin film PV solar cells

I.M. Dharmadasa 한국물리학회 2009 Current Applied Physics Vol.9 No.2

This paper summarises the latest developments in thin film solar cells based on CdTe, CuInGaSe2 and GaAs/AlGaAs absorber materials. After proposing a new model for CdS/CdTe solar cells, new designs based on graded bandgap multi-layer solar cells have been proposed for photovoltaic (PV) solar cell development. These new designs have been tested with well researched materials, GaAs/AlGaAs, and highest open circuit voltages of 1170 mV and fill factors of ~0.85 values were produced for initial growths and fabrications. This work has led to the identification of disadvantages of the tunnel junction approach, in the present manufacturing process. Recently, it has been shown that Fermi level pinning takes place at one of the four experimentally observed defect levels in CuInGaSe2/metal interfaces very similar to that of CdTe/metal contacts. These levels are at 0.77, 0.84, 0.93 and 1.03 eV with ±0.02 eV error and are situated above the valence band maximum. As a result, discrete values of open circuit voltages are observed and the situation is very similar to that of CdS/CdTe solar cells. It is becoming clear that Fermi level pinning due to defect levels dominates the performance in at least CdTe and CIGS thin film devices and future research should be directed to solving associated issues and hence improving the performance of PV solar cells. This paper summarises the latest developments in thin film solar cells based on CdTe, CuInGaSe2 and GaAs/AlGaAs absorber materials. After proposing a new model for CdS/CdTe solar cells, new designs based on graded bandgap multi-layer solar cells have been proposed for photovoltaic (PV) solar cell development. These new designs have been tested with well researched materials, GaAs/AlGaAs, and highest open circuit voltages of 1170 mV and fill factors of ~0.85 values were produced for initial growths and fabrications. This work has led to the identification of disadvantages of the tunnel junction approach, in the present manufacturing process. Recently, it has been shown that Fermi level pinning takes place at one of the four experimentally observed defect levels in CuInGaSe2/metal interfaces very similar to that of CdTe/metal contacts. These levels are at 0.77, 0.84, 0.93 and 1.03 eV with ±0.02 eV error and are situated above the valence band maximum. As a result, discrete values of open circuit voltages are observed and the situation is very similar to that of CdS/CdTe solar cells. It is becoming clear that Fermi level pinning due to defect levels dominates the performance in at least CdTe and CIGS thin film devices and future research should be directed to solving associated issues and hence improving the performance of PV solar cells.

염료감응형 태양전지와 열전발전소자를 결합한 복합 태양전지의 구조 및 특성

이동윤,송재성,이원재,김인성,정순종,Lee, Dong-Yoon,Song, Jae-Sung,Lee, Won-Jae,Kim, In-Sung,Jeong, Soon-Jong 한국전기전자재료학회 2005 전기전자재료학회논문지 Vol.18 No.4

The tandem solar cell composed of a dye-sensitized solar cell (DSC) and a thermoelectric generator (TEG) was designed. In such new cell, the characteristics of DSC and TEG were investigated. DSC uses the wavelength range of 380∼750 nm and has the maximum efficiency of below 10 %. If the solar light transmitted through DSC can be converted to heat energy, TEG can generate electric energy using this heat energy. By this means, it is possible to utilize most of solar energy in the wavelength range of 350∼3000 nm for electric generation and it can be expected to obtain higher solar energy conversion efficiency exceeding the known limit of maximum efficiency. For this purpose we suggest the tandem solar cell constructed with DSC and TEG. In this structure, DSC has a carbon nanotube film as a counter electrode of DSC in order to collect the solar light and convert it to heat energy. We measured the I-V characteristics of DSC and TEG, assembled to the tandem cell. As a result, it was shown that DSC with carbon nanotube and TEG had the efficiency of 9.1 % and 6.2 %, respectively. From this results, it is expected that the tandem solar cell of the new design has the possibility of enhanced conversion efficiency to exceed above 15 %.

Pentacene-assisted planarization of photo-active layers for high performance tandem organic photovoltaics

Yang, Feng,Kang, Dong-Won,Kim, Yong-Sang Elsevier 2018 SOLAR ENERGY -PHOENIX ARIZONA THEN NEW YORK- Vol.163 No.-

<P><B>Abstract</B></P> <P>In organic tandem solar cells, the morphology of the photo-active layers is not usually stable when their fabrication processes are made with several thermal treatments. Here, we report pentacene-assisted planar tandem organic photovoltaic device based on the active layers of poly(3-hexylthiophene) (P3HT) and (6,6)-phenyl C61-butyric acid methyl ester (PCBM), fabricated in air-ambient. An additive of pentacene was introduced into the active layers of the bottom sub-cells for planarization on their surfaces. The surface morphology of pentacene-based active layer was maintained to be flat from 80 to 160 °C, and allowed for fabricating the planar active layers and interconnecting layer of tandem devices against thermal treatment. State-of-the-art homo-tandem organic solar cells were achieved with an average power conversion efficiency (PCE) of 3.5%, while their best single junction solar cells of P3HT:PCBM achieved a PCE of 3.2%. We showed the first application of high performance tandem organic photovoltaics with three times of high temperature annealing processes at 160 °C. Our work demonstrates a practical way to design highly efficient tandem organic solar cells with other powerful and well-chosen bandgap energy active layers during thermal treatments.</P> <P><B>Highlights</B></P> <P> <UL> <LI> State-of-the-art homo-tandem organic solar cells were made in air-ambient. </LI> <LI> Surface of pentacene-added absorber was morphologically stable at 160 °C. </LI> <LI> Stable tandem cell against high temperature annealing three times at 160 °C. </LI> <LI> Homo-tandem solar cells increase PCE by 10% more than the best single cell. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Terminal Configuration and Growth Mechanism of III-V on Si-Based Tandem Solar Cell: A Review

Alamgeer,Muhammad Quddamah Khokhar,Muhammad Aleem Zahid,Hasnain Yousuf,한승용,Yifan Hu,김영국,Suresh Kumar Dhungel,이준신 한국전기전자재료학회 2023 전기전자재료학회논문지 Vol.36 No.5

Tandem or multijunction solar cells (MJSCs) can convert sunlight into electricity with higher efficiency (η) than single junction solar cells (SJSCs) by dividing the solar irradiance over sub-cells having distinct bandgaps. The efficiencies ofvarious common SJSC materials are close to the edge of their theoretical efficiency and hence there is a tremendous growing interest in utilizing the tandem/multijunction technique. Recently, III-V materials integration on a silicon substrate has been broadly investigated in the development of III-V on Si tandem solar cells. Numerous growth techniques such as heteroepitaxial growth, wafer bonding, and mechanical stacking are crucial for better understanding of high-quality III-V epitaxial layers on Si. As the choice of growth method and substrate selection can significantly impact the quality and performance of the resulting tandem cell and the terminal configuration exhibit a vital role in the overall proficiency. Parallel and Series-connected configurations have been studied, each with its advantage and disadvantages depending on the application and cell configuration. The optimization of both growth mechanisms and terminal configurations is necessary to further improve efficiency and lessen the cost of III-V on Si tandem solar cells. In this review article, we present an overview of the growth mechanisms and terminal configurations with the areas of research that are crucial for the commercialization of III-V on Si tandem solar cells.

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>

Thin Film Si-Ge/c-Si Tandem Junction Solar Cells with Optimum Upper Sub- Cell Structure

박진주 한국태양광발전학회 2020 Current Photovoltaic Research Vol.8 No.3

This study was trying to focus on achieving high efficiency of multi junction solar cell with thin film silicon solar cells. The proposed thin film Si-Ge/c-Si tandem junction solar cell concept with a combination of low-cost thin-film silicon solar cell technology and high-efficiency c-Si cells in a monolithically stacked configuration. The tandem junction solar cells using amorphous silicon germanium (a-SiGe:H) as an absorption layer of upper sub-cell were simulated through ASA (Advanced Semiconductor Analysis) simulator for acquiring the optimum structure. Graded Ge composition – effect of Eg profiling and inserted buffer layer between absorption layer and doped layer showed the improved current density (Jsc) and conversion efficiency (η). 13.11% conversion efficiency of the tandem junction solar cell was observed, which is a result of showing the possibility of thin film Si-Ge/c-Si tandem junction solar cell.

3-5족 적층형과 CuInGa(S,Se)2 및 Cu2ZnSn(S,Se)4 화합물반도체 박막태양전지

정연길 ( Yonkil Jeong ),박동원 ( Dong Won Park ),이재광 ( Jae Kwang Lee ),이재영 ( Jaeyoung Lee ) 한국공업화학회 2015 공업화학 Vol.26 No.5

신 기후변화대응(Post 2020)을 위한 대체에너지의 역할과 더불어 태양전지의 중요성이 높아져 가고 있다. 태양전지의 종류는 크게 재료관점에서 보면 유기물과 무기물 계열로 구분할 수 있지만 대규모 발전역할에서는 현재까지 실리콘과 같이 양산성과 안정성 기반의 무기물 태양전지가 주된 역할을 하고 있다. 특히 최근 몇 년간 화합물반도체 태양전지에 대한 연구는 급속도로 가속화되면서 3-5족 적층형 태양전지, chalcopyrite 계열 CuInGa(S,Se)2 (CIGSSe) 태양전지와 kesterite 계열 Cu2ZnSn(S,Se)4 (CZTSSe) 태양전지 연구가 대표적으로 주류를 이루어 왔다. 따라서 화합물반도체 태양전지에서 주류를 이루고 있는 3-5족 적층형, CIGSSe 및 CZTSSe 태양전지들의 연구개발동향 및 기술적인 주요내용들에 대해 소개하고자 한다. Solar cells with other alternative energies are being importantly recognized related with post-2020 climate change regime formation. In a point of view of materials, solar cells are classified to organic and inorganic solar cells which can provide a plant-scale electricity. In particular, recent studies about compound semiconductor solar cells, such as III-V tandem solar cells, chalcopyrite-series CIGSSe solar cells, and kesterite-series CZTSSe solar cells were rapidly accelerated. In this report, we introduce a research trend and technical issues for the compound semiconductor solar cells.

일체형 페로브스카이트/실리콘 탠덤 태양전지용 결정질 실리콘 하부 전지에 대한 고찰 II

서동철(Dongchul Suh) 호서대학교 공업기술연구소 2021 공업기술연구 논문집 Vol.40 No.1

페로브스카이트/실리콘 탠덤 태양전지는 약 4년 만에 28%(Oxford PV, 1 cm2)의 인증된 효율에 도달했으며, 대부분은 페로브스카이트 상부 전지와 결정질 실리콘 (c-Si) 하부 전지의 최적화된 설계를 바탕으로 한다. 이번 고찰에서는 성능을 향상시키기 위해 일체형 페로브스카이트/실리콘 탠덤 태양전지의 구조적 진화를 기반으로 하부 전지의 구조 조정에 중점을 둔다. 우선, c-Si 태양전지는 내열성에 따라 실리콘 동종 접합과 실리콘 이종 접합(SHJ) 소자로 분류되며 해당 구조적 특징이 제시된다. 이어서 c-Si 동종 접합 및 이종 접합 하부 전지를 기반으로 한 일체형 페로브스카이트/실리콘 탠덤 전지의 진화를 요약한다. 일체형 페로브스카이트/실리콘 탠덤 전지를 위한 c-Si 하단 전지의 적절한 후보는 주로 부동태화 이미터 및 후면 전지 소자, 터널 산화물 부동태화 접촉 전지 및 SHJ 소자를 포함한다. 결론적으로, 이번 연구는 페로브스카이트/실리콘 탠덤 전지에 대해 다른 부동태화 구조를 가진 c-Si 바닥 전지의 중요한 역할을 강조하여 탠덤 전지의 성능을 향상시키는 방향을 제시한다. Perovskite/silicon tandem solar cells have reached a certified efficiency of 28% (Oxford PV, 1cm2) in 4 years, and most of them are based on an optimized design in the perovskite top cell and crystalline silicon (c-Si) bottom cell. This review focuses on the restructuring of the bottom cell based on the structural evolution of the monolithic perovskite/silicon tandem solar cell to improve performance. First of all, c-Si solar cells are classified into silicon homo-junction and silicon hetero-junction (SHJ) devices according to their heat resistance, and their structural features are presented. The evolution of an monolithic perovskite/silicon tandem cells based on c-Si homo-junction and hetero-junction bottom cells are then summarized. Suitable candidates for c-Si bottom cells for monolithic perovskite/silicon tandem cells mainly include passivated emitter and rear cell devices, tunnel oxide passivated contact cells and SHJ devices. In conclusion, this study suggests a direction to improve the performance of tandem cells by emphasizing the important role of c-Si bottom cells with different passivation structures for perovskite/silicon tandem cells.