• Title, Summary, Keyword: Bandgap

Search Result 578, Processing Time 0.051 seconds

Organic-Inorganic Perovskite for Highly Efficient Tandem Solar Cells (고효율 적층형 태양전지를 위한 유무기 페로브스카이트)

  • Park, Ik Jae;Kim, Dong Hoe
    • Ceramist
    • /
    • v.22 no.2
    • /
    • pp.146-169
    • /
    • 2019
  • 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 process-possibility. As a result, they have been adopted either as a wide-bandgap top cell combined with narrow-bandgap silicon or CuInxGa(1-x)Se2 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 all-perovskite tandem solar cells, and 3) suitable semi-transparent conducting layer for efficient electrode or recombination layer in tandem solar cells.

Thin Film Solar Cell Simulation of A Function of P Buffer Layer Bandgap

  • Kim, Se-Jun;Choe, Hyeong-Uk;Lee, Yeong-Seok;Lee, Jun-Sin
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • /
    • pp.60-60
    • /
    • 2009
  • 기존의 박막 실리콘 태양전지는 TCO와 p-layer 사이의 Bandgap차이가 p-layer, i-layer, n-layer 사이의 Bandgap 차이보다 커서 TCO를 통과한 태양광이 p-layer에 흡수되기 전에 일정량 손실된다. 이를 해결하기 위하여, p-layer 위에 기존의 p-layer보다 높은 Bandgap을 갖는 p buffer layer가 추가된 박막 실리콘 태양전지 구조를 만들어서 흡수되는 태양광의 손실량을 줄이고, 변환효율을 높이고자 하였다. 실험은 ASA Simulator를 이용하여 진행하였으며, Simulation결과 1.92eV의 Bandgap을 갖는 p buffer layer의 추가로 인하여, 기존 10.64%에서 11.16%로 증가된 변환효율을 얻을 수 있었다. Bandgap뿐만 아니라 다른 요소의 최적화도 이루어진다면, 기존의 박막 실리콘 태양전지보다 훨씬 높은 변환효율을 갖는 박막 실리콘 태양전지를 설계 하는 것이 가능 할 것이다.

  • PDF

h-BN Graphene 합성에 의한 태양열전지

  • Choe, Hong-Yeong;U, Jun-Hyeok
    • Proceeding of EDISON Challenge
    • /
    • /
    • pp.405-407
    • /
    • 2015
  • Graphene의 bandgap이 0eV이고 hBN의 bandgap이 4~5eV라는 이기 때문에 두 물질을 혼합하였을 때 태양전지로 쓰기 좋은 1.2eV의 bandgap을 가지는 물질을 만들 수 있을 거라 생각된다. 이 점을 착안하여 hBN에 Carbon을 도핑시켜 1.2eV의 bandgap을 갖는 물질을 이론적으로 만들어 보았다.

  • PDF

Selection of Wide-Bandgap power device for series resonant half-bridge converter of Induction Cooker (직렬 공진 하프-브릿지 컨버터 인덕션 쿠커에 적용할 Wide-Bandgap power device 선정)

  • Kim, Jae-Keun;Kim, Seung-Gwon;Park, Sung-Min
    • Proceedings of the KIPE Conference
    • /
    • /
    • pp.159-160
    • /
    • 2018
  • 본 논문에서는 인덕션 쿠커의 토폴로지 중 하나인 직렬 공진 하프-브릿지 컨버터에 Wide-Bandgap 전력 반도체를 적용하여 전력 손실을 평가한다. 전력 반도체의 발전으로 Si-기반의 전력반도체를 대체할 GaN과 SiC의 Wide-Bandgap 소자들이 양산되고 있다. Wide-Bandgap 소자의 장점은 고주파수에서의 동작과 낮은 손실에 있다. 이에 인덕션 쿠커의 직렬 공진 하프-브릿지 컨버터에 Wide-Bandgap 전력반도체를 적용하여 전력 손실을 PSIM Thermal Module을 통해 평가하고 인덕션 쿠커에 적합한 소자를 선정한다.

  • PDF

Electrical and Optical Properties of Newly Synthesised Low Bandgap Polymer with Protic and Aprotic Ionic Liquids (양자성, 비양자성 이온성 액체와 새롭게 합성된 낮은 밴드갭을 갖는 고분자와의 상호작용에 의한 전기적,광학적 특성 연구)

  • Kim, Joong-Il;Kim, In-Tae
    • Journal of the Korean Applied Science and Technology
    • /
    • v.30 no.3
    • /
    • pp.461-471
    • /
    • 2013
  • Use of low bandgap polymers is the most suitable way to harvest a broader spectrum of solar radiations for solar cells. But, still there is lack of most efficient low bandgap polymer. In order to solve this problem, we have synthesised a new low bandgap polymer and investigated its interaction with the ILs to enhance its conductivity. ILs may undergo almost unlimited structural variations; these structural variations have attracted extensive attention in polymer studies. In addition to this, UV-Vis spectroscopy, confocal Raman spectroscopy and FT-IR spectroscopy results have revealed that all studied ILs (tributylmethylammonium methyl sulfate [$N_{1444}$][$MeSO_4$] from ammonium family) and 1-methylimidazolium chloride ([MIM]Cl, and 1-butyl-3-methylimidazolium chloride [Bmim]Cl from imidazolium family) has potential to interact with polymer. Further, protic ILs shows enhanced conductivity than aprotic ILs with low bandgap polymer. This study provides the combined effect of low bandgap polymer and ILs that may generate many theoretical and experimental opportunities.

Physical Properties of MoS2

  • Lee, Chang-Gu
    • Proceedings of the Korean Vacuum Society Conference
    • /
    • /
    • pp.100-100
    • /
    • 2013
  • Among recently discovered 2-dimensional materials, molybdenum disulfide has fascinating physical properties. It is atomically thin and is a semiconductor with with a similar level of bandgap with silicon. Especially, its properties get interesting when it becomes thinner. Its bandgap goes through bandgap transition from indirect to direct gap. Also its gap size increases as its thickness decreases. In this talk, I am going to present our recent work on characterization of its electrical and optical properties. We used Raman and PL spectroscopy to observe its property dependence on thickness. We fabricated electrical devices to study optimal condition for MoS2 devices. Also we synthesized large-area MoS2 films for devices applications.

  • PDF

Optimization of a Defected Ground Structure to Improve Electromagnetic Bandgap Performance

  • Kwon, Manseok;Kim, Myunghoi;Kam, Dong Gun
    • Journal of electromagnetic engineering and science
    • /
    • v.14 no.4
    • /
    • pp.346-348
    • /
    • 2014
  • A dispersion analysis is performed to estimate the stopband characteristics of electromagnetic bandgap (EBG) structures with defected ground structures (DGS) of various shapes. Design guidelines are suggested for both elliptical and rectangular DGS patterns that result in a maximum stopband bandwidth for a given perforation area. This method provides a basis for numerical optimization techniques that can be used in synthesizing DGS shapes to meet bandgap requirements and layout constraints.

박막태양전지 TCO/P 버퍼층 활성화를 위한 P-layer 최적화 Simulation

  • Jang, Ju-Yeon;Baek, Seung-Sin;Kim, Hyeon-Yeop;Lee, Jun-Sin
    • Proceedings of the Korean Vacuum Society Conference
    • /
    • /
    • pp.91-91
    • /
    • 2011
  • 박막태양전지의 높은 효율개선을 위해 TCO층과 p-layer 사이에 buffer layer를 넣어 Voc와 FF를 개선하는 연구가 진행되고 있다. 이에 buffer layer의 활성화 정도를 높이기 위해 p-layer을 최적화 시키고자한다. 이 실험에서 a-Si:B에 N2O를 도핑시켜 Bandgap Energy 2.0 eV, Activation Energy 0.4 eV인 a-SiOx:B 막을 제작하여 buffer layer로 사용하였고 이 buffer layer에 의한 cell의 효율 향상을 최적화 하기위해 ASA simulation을 이용해 p-layer의 Bandgap Energy와 Activation Energy를 가변 하여 보았다. 실험결과 p-layer의 Bandgap Energy 1.95 eV에서 buffer layer와 p-layer사이에서의 barrier가 최소가 됨을 확인 할 수 있었고 Actication Energy 0.5 eV에서 가장 높은 Voc를 가짐을 알 수 있었다. 본 연구를 통해 p-layer의 Bandgap Energy 1.95 eV, Activation Energy 0.5 eV에서 buffer layer를 활성화시키기 위한 p-layer의 최적화 조건을 구현해 볼 수 있었다.

  • PDF

Modified Low-Votlage CMOS Bandgap Voltage Reference with CTAT Compensation (개선된 CTAT 보상을 가지는 저전압 CMOS Bandgap Voltage Reference)

  • Kim, Jae-Bung;Cho, Seong-Ik
    • The Transactions of The Korean Institute of Electrical Engineers
    • /
    • v.61 no.5
    • /
    • pp.753-756
    • /
    • 2012
  • In this paper, a modified low-votlage CMOS bandgap voltage reference with CTAT compensation is presented. The proposed structure doesn't use PTAT current. The proposed structure is more simple than the existing structure and doesn't use the eighteen BJT. The modified low-votlage CMOS bandgap voltage reference with CTAT compensation has been successfully verified in a standard 0.18um CMOS process. The simulation results have confirmed that, with the minimum supply voltage of 1.25V, the output reference voltage at 549mV has a temperature coefficient of 12$ppm/^{\circ}C$ from $0^{\circ}C$ to $100^{\circ}C$.

Bandgap engineering of nanosized carbon dots through electron-accepting functionalization

  • Choi, Jongwan;Kim, Nakjoong;Oh, Jin-Woo;Kim, Felix Sunjoo
    • Journal of Industrial and Engineering Chemistry
    • /
    • v.65
    • /
    • pp.104-111
    • /
    • 2018
  • We report tuning of energy bandgap of nanosized carbon dots by chemical modification with electron-accepting moieties. The carbon dot derivatives were synthesized by oxidation and hydrothermal reaction, followed by addition/substitution reactions, resulting in uniform-sized carbon dots. Structural characterization and photophysical investigation were performed by applying various microscopic and spectroscopic techniques. The bandgap of the carbon dots was controlled by chemical functionalization with nitro and nitrile groups, as evidenced by the red-shift in the absorption and photoluminescence emission spectra. Calculations based on density functional theory were employed to support the observed bandgap tuning via functionalization of the carbon dots.