이 연구는 에너지 나노, 수상 번호 DE-SC0001013에서 에너지, 과학의 사무실의 미 교육부에 의해 투자 에너지 프론티어 연구 센터의 센터의 한 부분으로 지원되었다. 우리는 또한 이산화 티탄 박막 스퍼터링 및 굴절률 측정에 그들의 도움 박사 최대 장과 HP 연구소의 박사 지안 후아 양 감사드립니다.

나노 임프린트 몰드 1. 빈 폴리 디메틸 실록산을 준비 (PDMS) 기판 <ol><li> 실리콘 웨이퍼 처리 공정 <ol><li> 아세톤, 메탄올 및 이소프로판올로 세척하여 4 인치 실리콘 웨이퍼를 청소한다. </li><li> 이 질소 총을 이용한 드라이 불어. </li><li> 15 분 동안 담가 내부 (30 %의 과산화수소와 황산의 혼합물을 3 일) 피라나 용액을 사용하여 청소한다. </li><li> 탈 이온수로 씻어. 질소 총을 사용하여 건조 불어. </li><li> 유리 데시 케이 터에 웨이퍼를 놓습니다. 데시 케이 터에 제 (트리클로로)를 해제 한 방울 (20 방울 = 1 ml)에 추가한다. </li><li> 게이지가 -762 토르 표시 될 때까지 데시 케이 터를 펌프와 5 시간 동안 기다립니다. </li><li> 박리제로 처리 된 웨이퍼 아웃 보자. </li></ol></li><li> PDMS 필름의 제조 (나노 임프린트의 몰드로 사용) <ol><li> 실리콘 엘라스토머 염기 10g 및 경화제의 1g을 단다. </li><li> 같은 유리 비커에 추가. </li><li> STI는R 및 5 분 동안 유리 막대로 혼합한다. </li><li> 게이지가 모든 갇힌 공기 방울을 펌프 -762 토르 표시 될 때까지 진공 데시 케이 터에 혼합물을 넣어. </li><li> 처리 한 4 인치 실리콘 웨이퍼 상에 균등하게 확산. </li><li> PDMS 막을 경화 80 ° C에서 7 시간 동안 진공 오븐에서 위에 PDMS와 웨이퍼를 굽는다. </li></ol></li></ol> 2. (마스터 금형에서 중복) 나노 임프린트 몰드를 준비 <ol><li> 1500 rpm에서 30 초 동안 깨끗한 빈 실리콘 웨이퍼 상에 UV 경화성 레지스트 열두 방울 (20 방울 = 1 mL) 중 (15.2 %)을 스핀. </li><li> 조심스럽게 처리 한 실리콘 웨이퍼 오프 PDMS 막의 일부를 박리. </li><li> 경화 저항 자외선에 PDMS 필름을 넣고는 UV가 다음 5 분 레지스트를 벗겨 흡수 할 수 있습니다. </li><li> 두 번 같은 PDMS 막 위에 2.1-2.3 반복한다. 자외선은 각각 3 분 1 분 동안 저항을 사용하여 흡수시킬 것. </li><li> 실리콘 마스터 몰드에 (세 시간 자외선 흡수에 저항 후) PDMS 필름을 놓습니다. </li><li> 질소 환경 챔버에 넣어. </li><li> 5 분 동안 샘플을 치료하는 UV 램프를 켭니다. </li><li> PDMS 필름을 벗겨. UV 경화는 마스터 몰드의 네가티브 패턴을 유지할 PDMS 레지스트. </li><li> 사용 RF O 2 플라즈마 PDMS 몰드를 치료한다. (RF 전력 : 30 W, 압력 : 260 mTorr의 시간 : 1 분) </li><li> 2 시간 동안 박리제 한 방울 (20 방울 = 1 ml)로 진공 챔버에 PDMS 몰드를 놓는다. </li></ol> 3. 나노 임프린트 패턴 전송 <ol><li> 기판 상에 PMMA의 팔 방울 (20 방울 = 1 ㎖) (996k, 3.1 %)를 스핀은 3,500 rpm에서 50 초 동안 각인합니다. </li><li> 120 ℃에서 5 분 동안 열판을 굽는다. </li><li> 시료가 식을 때까지 기다립니다. </li><li> 동일 기판 상에 UV 여덟 방울 (20 방울 = 1 ㎖) 경화성은 (3.9 %)을 레지스트 스핀. </li><li> 샘플 (UV 모두 저항 및 PMMA)에 PDMS 몰드 (단계 2에서 제조)를 놓습니다. </li><li> 질소 환경 챔버에 넣어.</li><li> 5 분 동안 치료하는 UV 램프를 켭니다. </li><li> 필 오프 샘플 PDMS 몰드와 PDMS 몰드의 패턴 샘플에 전사 얻는다. </li></ol> 4. CR의 리프트 오프 (lift-off) 공정 <ol><li> 잔류 자외선의 레지스트 층과 PMMA를 반응성 이온 에칭 참고 : ICP 기계에 대한 SOP는 https://www.nanocenter.umd.edu/equipment/fablab/sops/etch-07/Oxford%20Chlorine%20Etcher%20SOP.pdf에서 찾을 수 있습니다 <ol><li> RIE ICP 시스템에 로그인합니다. </li><li> 빈 4 인치 실리콘 웨이퍼를로드합니다. 10 분 동안 깨끗한 레시피를 실행합니다. </li><li> 빈 실리콘 웨이퍼를 꺼내. </li><li> 다른 깨끗한 실리콘 웨이퍼 상에 샘플을 장착하고 시스템에로드합니다. </li><li> 자외선은 2 분 동안 에칭 레시피를 저항 실행 (제조법은 표 1에서 찾아 볼 수있다). </li><li> 샘플을 가져 가라. 빈 4 인치 실리콘 웨이퍼를로드합니다. 다시 실행 깨끗한 레시피를 10 분 동안 (표 1에서 찾아 볼 수있다). </li><li> 깨끗한 실리콘 웨이퍼 상에 샘플을 탑재하고 시스템에로드. </li><li> 2 분 동안 (표 1에서 찾을 수 있습니다) PMMA 에칭 레시피를 실행합니다. 참고 : 이제 잔류 에칭 된 레지스트 및 기판이 노출되어있다. </li></ol></li><li> CR E - 빔 증발 <ol><li> 전자 빔 증발기에 로그인합니다. </li><li> 챔버에 CR 금속 소스 및 샘플을로드합니다. </li><li> 두께 (20 ㎚) 및 증착 속도 (/ 초 0.03 nm의)를 설정합니다. </li><li> 필요한 진공 (10-7 토르)까지 실을 펌프하는 것은 도달한다. </li><li> 증착 프로세스를 시작한다. </li><li> 증착이 완료된 후 샘플을 가져 가라. </li></ol></li><li> 리프트 오프 (lift-off) CR 절차 <ol><li> 5 분 동안 초음파 교반 아세톤에 시료를 담그. </li><li> 아세톤, 메탄올, 이소프로판올로 세척하여 샘플을 청소합니다. 참고 : 전원이 해제됩니다 레지스트 및 기판 에칭 CR 마스크를 형성에 CR 증발. </li></ol></li></ol> 5. 이산화 티탄 출발지osition <ol><li> 로드 샘플. </li><li> 직류 마그네트론 스퍼터링 장치에 대한 매개 변수를 설정 <ol><li> 1.5 mTorr 이하의 챔버 압력, 100 SCCM의 아르곤 흐름과 130 W.의 스퍼터링 전력을 사용 </li><li> 27 ° C의 온도 및 20 rpm의 단계 회전 수를 사용한다. </li></ol></li><li> 스퍼터 공정을 시작하고 원하는 두께로 중지합니다. </li><li> 샘플을 가지고 3 시간 동안 300 ℃에서 산소 환경에서 이산화 티탄 필름을 어닐링. </li></ol> 6. 고 대비 격자 에칭 <ol><li> 유도 결합 플라즈마 (ICP), 반응성 이온 에칭 (RIE) 장치에 로그인. </li><li> 이산화 티탄 에칭 <ol><li> 빈 4 인치 실리콘 웨이퍼를 적재. </li><li> 시작하고 깨끗한 레시피를 실행 10 분 동안 (표 1에서 찾아 볼 수있다). </li><li> 빈 웨이퍼를로드 언로드 및 CR 마스크와 샘플을로드합니다. </li><li> 에칭 시간을 설정합니다. 이산화 티탄 에칭 레시피를 시작합니다. 에칭 공정 의지 자동matically 중지합니다. </li><li> 샘플을 언로드합니다. </li></ol></li><li> SiO2를 에칭 <ol><li> SiO2를 에칭 조리법을 사용 제외 단계를 반복 5.2. </li></ol></li></ol> 7. 반사율 측정 <ol><li> 로그인 및 측정 시스템을 켭니다. </li><li> 샘플 홀더에 반사율 표준 거울을 놓고 광학 경로를 맞 춥니 다. </li><li> 100 %의 반사율을 보정 시스템. </li><li> 반사율 표준 거울을 벗고 HCG를 놓습니다. </li><li> HCG의 반사율을 측정합니다. </li><li> 데이터를 저장하고 측정 시스템의 로그 아웃. </li></ol>

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The authors have nothing to disclose.

우선, 이산화 티탄 막의 품질 HCG 성능에 매우 중요하다. 이산화 티탄 막은 적은 손실 및 표면 거칠기를 갖는 경우, 반사율 피크는 높을 것이다. 광학 모드가 한정 HCG의 평탄한 야기하고 넓은 반사 밴드를 제공 할 수있는 인덱스 높은 콘트라스트에 의해 향상되기 때문에 더 높은 굴절률과 이산화 티탄 막도 바람직하다. 둘째로, 제조 오차 HCG에 상당한 ?...

현대 사회는 재생 가능한 에너지 원으로 에너지 소비의 상당 부분을 움직이지 않고 생존 할 것이다. 이 일어날 수 있도록하기 위해, 우리는 가까운 미래에 석유 기반 에너지 원보다 낮은 비용으로 신 재생 에너지를 수확 할 수있는 방법을 찾을 수있다. 태양 에너지는 지구상에서 가장 풍부한 신 재생 에너지입니다. 진행됨 많은 태양 에너지를 수확하여 이루어진 것을에도 불구하고, 석유 계 에너지 원과 경쟁 여전히 매우 도전적이다. 태양 전지의 효율을 개선하는 것은 태양 에너지 수확의 시스템 비용을 절감 할 수있는 가장 효율적인 방법 중 하나이다. 그것이 고가 탠덤 다중 접합 태양 전지 (2)을 악용 경제성하므로 광학 렌즈 및 접시 반사기는 일반적으로, 작은 면적의 태양 전지에 태양 광이 입사 높은 농도를 달성하기 위해 가장 집중된 광 (CPV) 시스템 (1)에 사용되는 CPV 시스템 및 합리적인 유지동시에 비용. 그들은 일반적으로 더 넓은 태양 스펙트럼 응답 및보다 전반적으로 높은 변환 효율을 갖지만 그러나, 통상 태양 전지의 대 면적 분할을 필요로 가장 비 농축 광전지 시스템의 경우, 고가의 탠덤 태양 전지는, 혼입 될 수 없다 단일 접합 태양 전지 3. 최근 평행 스펙트럼 분할 광학계의 도움 (즉 분산 요소)와, 병렬 스펙트럼 분할 광전지 기술 4 만들었다 그것을 가능한 유사하거나 더 나은 스펙트럼 범위와 변환 효율이 고가의 탠덤 태양 전지를 사용하지 않고 달성 될 수있다. 다른 태양 스펙트럼 대역으로 분할 될 수 있고, 각 대역은 흡수되고 특화된 단일 접합 태양 전지에 의해 전기로 전환시킬 수있다. 이러한 방식으로, CPV 시스템의 비싼 탠덤 태양 전지는 단일 접합 태양 전지의 병렬 분포로 대체 될 수있다성능에 타협하지 않고들. 이 보고서에서 설계된 분산 요소는 개선 된 태양 광 전기 변환 효율 및 비용 절감을위한 병렬 스펙트럼 분리를 실현할 (접시 반사기에 기초하는) 반사 CPV 시스템에 적용될 수있다. 적층 높은 콘트라스트 격자 (HCG)도 5는 광 대역 반사기로 일 HCG의 각 계층을 설계함으로써 분산 요소로서 사용된다. 구조와 분산 요소의 매개 변수가 수치 적으로 최적화되어 있습니다. 또한, 유전체를 사용하여 분산 요소에 대한 높은 콘트라스트 격자의 제작 (이산화 티탄), 스퍼터링, 나노 임프린트 리소그래피 (6) 및 반응성 이온 에칭이 연구되고 설명된다.

<table><tbody><tr><td>184 Silcone elastomer kit</td><td>Sylgard</td><td></td><td>Polydimethylsiloxane (PDMS)</td></tr><tr><td>4 inch silicon wafer</td><td>Universitywafer</td><td></td><td></td></tr><tr><td>4 inch fused silica wafer</td><td>Universitywafer</td><td></td><td></td></tr><tr><td>Poly(methyl methacrylate)</td><td>Sigma-Aldrich</td><td>182265</td><td></td></tr><tr><td>UV-curable resist</td><td></td><td></td><td>Nor available on market</td></tr><tr><td>PlasmaLab System 100</td><td>Oxford Instruments</td><td></td><td>ICP IRE machine</td></tr><tr><td>UV curing system for nanoimprint fabrication</td><td></td><td></td><td>Not available on market</td></tr><tr><td>Ocean Optics HR-4000&amp;nbsp;</td><td>Ocean Optics</td><td>HR-4000</td><td>Spectrometer with normal detector</td></tr><tr><td>Lambda 950 UV / VIS</td><td>PerkinElmer</td><td></td><td>spectrometer with hemisphere intergration detector</td></tr><tr><td>JSM-7001F-LV</td><td>JEOL</td><td></td><td>Field emission SEM</td></tr><tr><td>DC magnetron sputtering machine</td><td></td><td></td><td>Equipment is in HP labs, who helped us to sputter the TiO&lt;sub&gt;2&lt;/sub&gt;</td></tr><tr><td>Metal e-beam evaporator</td><td>Temescal</td><td>BJD-1800</td><td></td></tr></tbody></table>

fabrication of high contrast gratings for the spectrum splitting dispersive element in a concentrated photovoltaic system

High contrast gratings are designed and fabricated and its application is proposed in a parallel spectrum splitting dispersive element that can improve the solar conversion efficiency of a concentrated photovoltaic system. The proposed system will also lower the solar cell cost in the concentrated photovoltaic system by replacing the expensive tandem solar cells with the cost-effective single junction solar cells. The structures and the parameters of high contrast gratings for the dispersive elements were numerically optimized. The large-area fabrication of high contrast gratings was experimentally demonstrated using nanoimprint lithography and dry etching. The quality of grating material and the performance of the fabricated device were both experimentally characterized. By analyzing the measurement results, the possible side effects from the fabrication processes are discussed and several methods that have the potential to improve the fabrication processes are proposed, which can help to increase the optical efficiency of the fabricated devices.

도 1은 농축 광전지 시스템에서 분산 요소 (다층 높은 콘트라스트 격자 (HCG))의 구현을 도시한다. 태양 광은 제 차 미러에 의해 반사 된 빔이 반사되고, 다른 파장의 상이한 대역들로 분할되어 반사 분산 요소에 충돌한다. 각 대역은 전기 가장 흡수 및 전환 용 태양 전지 어레이상의 특정 위치에 충돌한다. 본 시스템의 핵심은 설계 및 HCG의 여러 층으로 구성되는 분산 요소의 구현이다. <...

Watch this Scientific Journal Video about Fabrication of High Contrast Gratings for the Spectrum Splitting Dispersive Element in a Concentrated Photovoltaic System at JoVE.com

Fabrication of High Contrast Gratings for the Spectrum Splitting Dispersive Element in a Concentrated Photovoltaic System

The fabrication of high contrast gratings as the parallel spectrum splitting dispersive element in a concentrated photovoltaic system is demonstrated. Fabrication processes including nanoimprint lithography, TiO2 sputtering and reactive ion etching are described. Reflectance measurement results are used to characterize the optical performance.

집중 태양 광 발전 시스템의 스펙트럼 분할 흩어 요소에 대한 고 대비 격자의 제작

High contrast gratings are designed and fabricated and its application is proposed in a parallel spectrum splitting dispersive element that can improve ...

fabrication-high-contrast-gratings-for-spectrum-splitting-dispersive

Universidad de Cartagena UDEC

Research

JoVE Journal

Engineering

10.7K 조회수.  University of Sothern California. The fabrication of high contrast gratings as the parallel spectrum splitting dispersive element in a concentrated photovoltaic system is demonstrated. Fabrication processes including nanoimprint lithography, TiO2 sputtering and reactive ion etching are described. Reflectance measurement results are used to characterize the optical performance. 

비디오: Fabrication of High Contrast Gratings for the Spectrum Splitting Dispersive Element in a Concentrated Photovoltaic System

Polycrystalline Silicon Thin-film Solar cells with Plasmonic-enhanced Light-trapping

One of major approaches to cheaper solar cells is reducing the amount of semiconductor material used for their fabrication and making cells thinner. To compensate for lower light absorption such physically thin devices have to incorporate light-trapping which increases their optical thickness. Light scattering by textured surfaces is a common technique but it cannot be universally applied to all solar cell technologies. Some cells, for example those made of evaporated silicon, are planar as produced and they require an alternative light-trapping means suitable for planar devices. Metal nanoparticles formed on planar silicon cell surface and capable of light scattering due to surface plasmon resonance is an effective approach.
The paper presents a fabrication procedure of evaporated polycrystalline silicon solar cells with plasmonic light-trapping and demonstrates how the cell quantum efficiency improves due to presence of metal nanoparticles.
To fabricate the cells a film consisting of alternative boron and phosphorous doped silicon layers is deposited on glass substrate by electron beam evaporation. An Initially amorphous film is crystallised and electronic defects are mitigated by annealing and hydrogen passivation. Metal grid contacts are applied to the layers of opposite polarity to extract electricity generated by the cell. Typically, such a ~2 &mu;m thick cell has a short-circuit current density (Jsc) of 14-16 mA/cm2, which can be increased up to 17-18 mA/cm2 (~25% higher) after application of a simple diffuse back reflector made of a white paint.
To implement plasmonic light-trapping a silver nanoparticle array is formed on the metallised cell silicon surface. A precursor silver film is deposited on the cell by thermal evaporation and annealed at 23&deg;C to form silver nanoparticles. Nanoparticle size and coverage, which affect plasmonic light-scattering, can be tuned for enhanced cell performance by varying the precursor film thickness and its annealing conditions. An optimised nanoparticle array alone results in cell Jsc enhancement of about 28%, similar to the effect of the diffuse reflector. The photocurrent can be further increased by coating the nanoparticles by a low refractive index dielectric, like MgF2, and applying the diffused reflector. The complete plasmonic cell structure comprises the polycrystalline silicon film, a silver nanoparticle array, a layer of MgF2, and a diffuse reflector. The Jsc for such cell is 21-23 mA/cm2, up to 45% higher than Jsc of the original cell without light-trapping or ~25% higher than Jsc for the cell with the diffuse reflector only.
Introduction
Light-trapping in silicon solar cells is commonly achieved via light scattering at textured interfaces. Scattered light travels through a cell at oblique angles for a longer distance and when such angles exceed the critical angle at the cell interfaces the light is permanently trapped in the cell by total internal reflection (Animation 1: Light-trapping). Although this scheme works well for most solar cells, there are developing technologies where ultra-thin Si layers are produced planar (e.g. layer-transfer technologies and epitaxial c-Si layers) 1 and or when such layers are not compatible with textures substrates (e.g. evaporated silicon) 2. For such originally planar Si layer alternative light trapping approaches, such as diffuse white paint reflector 3, silicon plasma texturing 4 or high refractive index nanoparticle reflector 5 have been suggested.
Metal nanoparticles can effectively scatter incident light into a higher refractive index material, like silicon, due to the surface plasmon resonance effect 6. They also can be easily formed on the planar silicon cell surface thus offering a light-trapping approach alternative to texturing. For a nanoparticle located at the air-silicon interface the scattered light fraction coupled into silicon exceeds 95% and a large faction of that light is scattered at angles above critical providing nearly ideal light-trapping condition (Animation 2: Plasmons on NP). The resonance can be tuned to the wavelength region, which is most important for a particular cell material and design, by varying the nanoparticle average size, surface coverage and local dielectric environment 6,7. Theoretical design principles of plasmonic nanoparticle solar cells have been suggested 8. In practice, Ag nanoparticle array is an ideal light-trapping partner for poly-Si thin-film solar cells because most of these design principle are naturally met. The simplest way of forming nanoparticles by thermal annealing of a thin precursor Ag film results in a random array with a relatively wide size and shape distribution, which is particularly suitable for light-trapping because such an array has a wide resonance peak, covering the wavelength range of 700-900 nm, important for poly-Si solar cell performance. The nanoparticle array can only be located on the rear poly-Si cell surface thus avoiding destructive interference between incident and scattered light which occurs for front-located nanoparticles 9. Moreover, poly-Si thin-film cells do not requires a passivating layer and the flat base-shaped nanoparticles (that naturally result from thermal annealing of a metal film) can be directly placed on silicon further increases plasmonic scattering efficiency due to surface plasmon-polariton resonance 10.
The cell with the plasmonic nanoparticle array as described above can have a photocurrent about 28% higher than the original cell. However, the array still transmits a significant amount of light which escapes through the rear of the cell and does not contribute into the current. This loss can be mitigated by adding a rear reflector to allow catching transmitted light and re-directing it back to the cell. Providing sufficient distance between the reflector and the nanoparticles (a few hundred nanometers) the reflected light will then experience one more plasmonic scattering event while passing through the nanoparticle array on re-entering the cell and the reflector itself can be made diffuse - both effects further facilitating light scattering and hence light-trapping. Importantly, the Ag nanoparticles have to be encapsulated with an inert and low refractive index dielectric, like MgF2 or SiO2, from the rear reflector to avoid mechanical and chemical damage 7. Low refractive index for this cladding layer is required to maintain a high coupling fraction into silicon and larger scattering angles, which are ensured by the high optical contrast between the media on both sides of the nanoparticle, silicon and dielectric 6. The photocurrent of the plasmonic cell with the diffuse rear reflector can be up to 45% higher than the current of the original cell or up to 25% higher than the current of an equivalent cell with the diffuse reflector only.

Polycrystalline silicon thin-film solar cells on glass are fabricated by deposition of boron and phosphorous doped silicon layers followed by crystallisation, defect passivation and metallisation. Plasmonic light-trapping is introduced by forming Ag nanoparticles on the silicon cell surface capped with a diffused reflector resulting in ~45% photocurrent enhancement.

Plasmonic 강화된 라이트 - 트래핑과 다결정 실리콘 박막 태양 전지

One of major approaches to cheaper solar cells is reducing the amount of semiconductor material used for their fabrication and making cells thinner. To ...

연구

공학

Harvesting Solar Energy by Means of Charge-Separating Nanocrystals and Their Solids

Conjoining different semiconductor materials in a single nano-composite provides synthetic means for the development of novel optoelectronic materials offering a superior control over the spatial distribution of charge carriers across material interfaces. As this study demonstrates, a combination of donor-acceptor nanocrystal (NC) domains in a single nanoparticle can lead to the realization of efficient photocatalytic1-5 materials, while a layered assembly of donor- and acceptor-like nanocrystals films gives rise to photovoltaic materials.
Initially the paper focuses on the synthesis of composite inorganic nanocrystals, comprising linearly stacked ZnSe, CdS, and Pt domains, which jointly promote photoinduced charge separation. These structures are used in aqueous solutions for the photocatalysis of water under solar radiation, resulting in the production of H2 gas. To enhance the photoinduced separation of charges, a nanorod morphology with a linear gradient originating from an intrinsic electric field is used5. The inter-domain energetics are then optimized to drive photogenerated electrons toward the Pt catalytic site while expelling the holes to the surface of ZnSe domains for sacrificial regeneration (via methanol). Here we show that the only efficient way to produce hydrogen is to use electron-donating ligands to passivate the surface states by tuning the energy level alignment at the semiconductor-ligand interface. Stable and efficient reduction of water is allowed by these ligands due to the fact that they fill vacancies in the valence band of the semiconductor domain, preventing energetic holes from degrading it. Specifically, we show that the energy of the hole is transferred to the ligand moiety, leaving the semiconductor domain functional. This enables us to return the entire nanocrystal-ligand system to a functional state, when the ligands are degraded, by simply adding fresh ligands to the system4.
To promote a photovoltaic charge separation, we use a composite two-layer solid of PbS and TiO2 films. In this configuration, photoinduced electrons are injected into TiO2 and are subsequently picked up by an FTO electrode, while holes are channeled to a Au electrode via PbS layer6. To develop the latter we introduce a Semiconductor Matrix Encapsulated Nanocrystal Arrays (SMENA) strategy, which allows bonding PbS NCs into the surrounding matrix of CdS semiconductor. As a result, fabricated solids exhibit excellent thermal stability, attributed to the heteroepitaxial structure of nanocrystal-matrix interfaces, and show compelling light-harvesting performance in prototype solar cells7.

A general strategy for the development of charge-separating semiconductor nanocrystal composites deployable for solar energy production is presented. We show that assembly of donor-acceptor nanocrystal domains in a single nanoparticle geometry gives rise to a photocatalytic function, while bulk-heterojunctions of donor-acceptor nanocrystal films can be used for photovoltaic energy conversion.

충전 분리 Nanocrystals와 고체를 통해 태양 에너지를 수확

Conjoining different semiconductor materials in a single nano-composite provides synthetic means for the development of novel optoelectronic materials ...

Using Neutron Spin Echo Resolved Grazing Incidence Scattering to Investigate Organic Solar Cell Materials

The spin echo resolved grazing incidence scattering (SERGIS) technique has been used to probe the length-scales associated with irregularly shaped crystallites. Neutrons are passed through two well defined regions of magnetic field; one before and one after the sample. The two magnetic field regions have opposite polarity and are tuned such that neutrons travelling through both regions, without being perturbed, will undergo the same number of precessions in opposing directions. In this case the neutron precession in the second arm is said to &#34;echo&#34; the first, and the original polarization of the beam is preserved. If the neutron interacts with a sample and scatters elastically the path through the second arm is not the same as the first and the original polarization is not recovered. Depolarization of the neutron beam is a highly sensitive probe at very small angles (&#60;50&#160;&#956;rad) but still allows a high intensity, divergent beam to be used. The decrease in polarization of the beam reflected from the sample as compared to that from the reference sample can be directly related to structure within the sample.
In comparison to scattering observed in neutron reflection measurements the SERGIS signals are often weak and are unlikely to be observed if the in-plane structures within the sample under investigation are dilute, disordered, small in size and polydisperse or the neutron scattering contrast is low. Therefore, good results will most likely be obtained using the SERGIS technique if the sample being measured consist of thin films on a flat substrate and contain scattering features that contains a high density of moderately sized features (30 nm to 5 &#181;m) which scatter neutrons strongly or the features are arranged on a lattice. An advantage of the SERGIS technique is that it can probe structures in the plane of the sample.

Progress has been made in utilizing spin echo resolved grazing incidence scattering (SERGIS) as a neutron scattering technique to probe the length-scales in irregular samples. Crystallites of [6,6]-phenyl-C61-butyric acid methyl ester have been probed using the SERGIS technique and the results confirmed by optical and atomic force microscopy.

중성자 스핀 에코 사용 하 여 방목 발생률 을 해결 하는 유기 태양 전지 물질을 조사 하기 위해

The spin echo resolved grazing incidence scattering (SERGIS) technique has been used to probe the length-scales associated with irregularly shaped ...

Integration of Light Trapping Silver Nanostructures in Hydrogenated Microcrystalline Silicon Solar Cells by Transfer Printing

One of the potential applications of metal nanostructures is light trapping in solar cells, where unique optical properties of nanosized metals, commonly known as plasmonic effects, play an important role. Research in this field has, however, been impeded owing to the difficulty of fabricating devices containing the desired functional metal nanostructures. In order to provide a viable strategy to this issue, we herein show a transfer printing-based approach that allows the quick and low-cost integration of designed metal nanostructures with a variety of device architectures, including solar cells. Nanopillar poly(dimethylsiloxane) (PDMS) stamps were fabricated from a commercially available nanohole plastic film as a master mold. On this nanopatterned PDMS stamps, Ag films were deposited, which were then transfer-printed onto block copolymer (binding layer)-coated hydrogenated microcrystalline Si (&#181;c-Si:H) surface to afford ordered Ag nanodisk structures. It was confirmed that the resulting Ag nanodisk-incorporated &#181;c-Si:H solar cells show higher performances compared to a cell without the transfer-printed Ag nanodisks, thanks to plasmonic light trapping effect derived from the Ag nanodisks. Because of the simplicity and versatility, further device application would also be feasible thorough this approach.

A viable transfer printing-based methodology to introduce plasmonic metal nanostructures in solar cells is described. Using nanopillar poly(dimethylsiloxane) stamps, an Ag-based ordered nanodisk array was integrated with standard hydrogenated microcrystalline Si solar cells, which led to improved device performances due to plasmonic light trapping.

전송 인쇄하여 수소 첨가 미세 결정 실리콘 태양 전지에 빛 트래핑 실버 나노 구조의 통합

One of the potential applications of metal nanostructures is light trapping in solar cells, where unique optical properties of nanosized metals, commonly ...

Printing Fabrication of Bulk Heterojunction Solar Cells and In Situ Morphology Characterization

Polymer-based materials hold promise as low-cost, flexible efficient photovoltaic devices. Most laboratory efforts to achieve high performance devices have used devices prepared by spin coating, a process that is not amenable to large-scale fabrication. This mismatch in device fabrication makes it difficult to translate quantitative results obtained in the laboratory to the commercial level, making optimization difficult. Using a mini-slot die coater, this mismatch can be resolved by translating the commercial process to the laboratory and characterizing the structure formation in the active layer of the device in real time and in situ as films are coated onto a substrate. The evolution of the morphology was characterized under different conditions, allowing us to propose a mechanism by which the structures form and grow. This mini-slot die coater offers a simple, convenient, material efficient route by which the morphology in the active layer can be optimized under industrially relevant conditions. The goal of this protocol is to show experimental details of how a solar cell device is fabricated using a mini-slot die coater and technical details of running in situ structure characterization using the mini-slot die coater.

Printing Fabrication of Bulk Heterojunction Solar Cells and In Situ Morphology Characterization

Here, we present a protocol to fabricate organic thin film solar cells using a mini-slot die coater and related in-line structure characterizations using synchrotron scattering techniques.

벌크 이종 접합 태양 전지의 인쇄 제작 및<em&gt; 현장에서</em&gt; 형태학 특성

Polymer-based materials hold promise as low-cost, flexible efficient photovoltaic devices. Most laboratory efforts to achieve high performance devices ...

Fabrication of Fully Solution Processed Inorganic Nanocrystal Photovoltaic Devices

We demonstrate a method for the preparation of fully solution processed inorganic solar cells from a spin and spray coating deposition of nanocrystal inks. For the photoactive absorber layer, colloidal CdTe and CdSe nanocrystals (3-5 nm) are synthesized using an inert hot injection technique and cleaned with precipitations to remove excess starting reagents. Similarly, gold nanocrystals (3-5 nm) are synthesized under ambient conditions and dissolved in organic solvents. In addition, precursor solutions for transparent conductive indium tin oxide (ITO) films are prepared from solutions of indium and tin salts paired with a reactive oxidizer. Layer-by-layer, these solutions are deposited onto a glass substrate following annealing (200-400 &#176;C) to build the nanocrystal solar cell (glass/ITO/CdSe/CdTe/Au). Pre-annealing ligand exchange is required for CdSe and CdTe nanocrystals where films are dipped in NH4Cl:methanol to replace long-chain native ligands with small inorganic Cl- anions. NH4Cl(s) was found to act as a catalyst for the sintering reaction (as a non-toxic alternative to the conventional CdCl2(s) treatment) leading to grain growth (136&#177;39 nm) during heating. The thickness and roughness of the prepared films are characterized with SEM and optical profilometry. FTIR is used to determine the degree of ligand exchange prior to sintering, and XRD is used to verify the crystallinity and phase of each material. UV/Vis spectra show high visible light transmission through the ITO layer and a red shift in the absorbance of the cadmium chalcogenide nanocrystals after thermal annealing. Current-voltage curves of completed devices are measured under simulated one sun illumination. Small differences in deposition techniques and reagents employed during ligand exchange have been shown to have a profound influence on the device properties. Here, we examine the effects of chemical (sintering and ligand exchange agents) and physical treatments (solution concentration, spray-pressure, annealing time and annealing temperature) on photovoltaic device performance.

This protocol describes the synthesis and solution deposition of inorganic nanocrystals layer by layer to produce thin film electronics on non-conductive surfaces. Solvent-stabilized inks can produce complete photovoltaic devices on glass substrates via spin and spray coating following post-deposition ligand exchange and sintering.

완전 해결 가공 된 무기 나노 결정 태양 광 발전 장치의 제작

We demonstrate a method for the preparation of fully solution processed inorganic solar cells from a spin and spray coating deposition of nanocrystal ...

Influence of Hybrid Perovskite Fabrication Methods on Film Formation, Electronic Structure, and Solar Cell Performance

Hybrid organic/inorganic halide perovskites have lately been a topic of great interest in the field of solar cell applications, with the potential to achieve device efficiencies exceeding other thin film device technologies. Yet, large variations in device efficiency and basic physical properties are reported. This is due to unintentional variations during film processing, which have not been sufficiently investigated so far. We therefore conducted an extensive study of the morphology and electronic structure of a large number of CH3NH3PbI3 perovskite where we show how the preparation method as well as the mixing ratio of educts methylammonium iodide and lead(II) iodide impact properties like film formation, crystal structure, density of states, energy levels, and ultimately the solar cell performance.

We present an extensive study on the effects of different fabrication methods for organic/inorganic perovskite thin films by comparing crystal structures, density of states, energy levels, and ultimately the solar cell performance.

필름 형성에 하이브리드 페 로브 스카이 트 제조 방법, 전자 구조 및 태양 전지 성능의 영향

Hybrid organic/inorganic halide perovskites have lately been a topic of great interest in the field of solar cell applications, with the potential to ...

화학

Indoor Experimental Assessment of the Efficiency and Irradiance Spot of the Achromatic Doublet on Glass (ADG) Fresnel Lens for Concentrating Photovoltaics

We present a method to characterize achromatic Fresnel lenses for photovoltaic applications. The achromatic doublet on glass (ADG) Fresnel lens is composed of two materials, a plastic and an elastomer, whose dispersion characteristics (refractive index variation with wavelength) are different. We first designed the lens geometry and then used ray-tracing simulation, based on the Monte Carlo method, to analyze its performance from the point of view of both optical efficiency and the maximum attainable concentration. Afterwards, ADG Fresnel lens prototypes were manufactured using a simple and reliable method. It consists of a prior injection of plastic parts and a consecutive lamination, together with the elastomer and a glass substrate to fabricate the parquet of ADG Fresnel lenses. The accuracy of the manufactured lens profile is examined using an optical microscope while its optical performance is evaluated using a solar simulator for concentrator photovoltaic systems. The simulator is composed of a xenon flash lamp whose emitted light is reflected by a parabolic mirror. The collimated light has a spectral distribution and an angular aperture similar to the real Sun. We were able to assess the optical performance of the ADG Fresnel lenses by taking photographs of the irradiance spot cast by the lens using a charge-coupled device (CCD) camera and measuring the photocurrent generated by several types of multi junction (MJ) solar cells, which have been previously characterized at a solar simulator for concentrator solar cells. These measurements have demonstrated the achromatic behavior of ADG Fresnel lenses and, as a consequence, the suitability of the modelling and manufacturing methods.

Indoor Experimental Assessment of the Efficiency and Irradiance Spot of the Achromatic Doublet on Glass ADG Fresnel Lens for Concentrating Photovoltaics

The achromatic doublet on glass (ADG) Fresnel lens makes use of two materials with differing dispersion to reduce chromatic aberration and increase attainable concentration. In this paper, a protocol for the complete characterization of the ADG Fresnel lens is presented.

실내 실험 평가의 효율성과 집중 태양광 발전에 대 한 유리 (ADG) 프레넬 렌즈에 무색 남자 용 상의의 Irradiance 자리

We present a method to characterize achromatic Fresnel lenses for photovoltaic applications. The achromatic doublet on glass (ADG) Fresnel lens is ...

Developing High Performance GaP/Si Heterojunction Solar Cells

To improve the efficiency of Si-based solar cells beyond their Shockley-Queisser limit, the optimal path is to integrate them with III-V-based solar cells. In this work, we present high performance GaP/Si heterojunction solar cells with a high Si minority-carrier lifetime and high crystal quality of epitaxial GaP layers. It is shown that by applying phosphorus (P)-diffusion layers into the Si substrate and a SiNx layer, the Si minority-carrier lifetime can be well-maintained during the GaP growth in the molecular beam epitaxy (MBE). By controlling the growth conditions, the high crystal quality of GaP was grown on the P-rich Si surface. The film quality is characterized by atomic force microscopy and high-resolution x-ray diffraction. In addition, MoOx was implemented as a hole-selective contact that led to a significant increase in the short-circuit current density. The achieved high device performance of the GaP/Si heterojunction solar cells establishes a path for further enhancement of the performance of Si-based photovoltaic devices.

Here, we present a protocol to develop high-performance GaP/Si heterojunction solar cells with a high Si minority-carrier lifetime.

높은 성능 격차/Si Heterojunction 태양 전지 개발

To improve the efficiency of Si-based solar cells beyond their Shockley-Queisser limit, the optimal path is to integrate them with III-V-based solar ...

In situ Grazing Incidence Small Angle X-ray Scattering on Roll-To-Roll Coating of Organic Solar Cells with Laboratory X-ray Instrumentation

We present an in-house, in situ Grazing Incidence Small Angle X-ray Scattering (GISAXS) experiment, developed to probe the drying kinetics of roll-to-roll slot-die coating of the active layer in organic photovoltaics (OPVs), during deposition. For this demonstration, the focus is on the combination of P3HT:O-IDTBR and P3HT:EH-IDTBR, which have different drying kinetics and device performance, despite their chemical structure only varying slightly by the sidechain of the small molecule acceptor. This article provides a step-by-step guide to perform an in situ GISAXS experiment and demonstrates how to analyze and interpret the results. Usually, performing this type of in situ X-ray experiments to investigate the drying kinetics of the active layer in OPVs relies on access to synchrotrons. However, by using and further developing the method described in this paper, it is possible to perform experiments with a coarse temporal and spatial resolution, on a day-to-day basis to gain fundamental insight in the morphology of drying inks.

This paper is a demonstration and a guideline to perform and analyze in-house (with a laboratory X-ray instrument) in situ GISAXS experiments of drying inks on roll-to-roll slot-die coated, non-fullerene organic photovoltaics.

실험실 X 선 계측기와 유기 태양 전지의 롤 투 롤 코팅에 작은 각도 X 선 산란 시

We present an in-house, in situ Grazing Incidence Small Angle X-ray Scattering (GISAXS) experiment, developed to probe the drying kinetics of roll-to-roll ...