Name: recombination dynamics in thin-film photovoltaic materials via time-resolved microwave conductivity
Uploaded: 2017-03-06T13:00:00.000+00:00
Duration: 11 min 30 s
Description: Watch this Scientific Journal Video about Recombination Dynamics in Thin-film Photovoltaic Materials via Time-resolved Microwave Conductivity at JoVE.com

Acknowledgment is made to the Australian Research Council (LE130100146, DP160103008). JAG is supported via an Australian Postgraduate Award, and DRM by an ARC Future Fellowship (FT130100214). We thank Nikos Kopidakis for helpful discussions.

<ol>
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The authors have nothing to disclose.

부 (Trmc) 기법 광유 전하 캐리어 역학에 대한 풍부한 정보를 제공 할 수 있지만,이 도전성의 간접 측정이므로, 결과를 해석 할 때주의 할 필요가 관심. 부 (Trmc) 기술은 전체 이동도를 측정하고, 전자와 정공 이동도를 구별하는 데 사용할 수 없다. 변화가 작은 (&lt;5 %) 16 때만 도전성 반사 전력의 변화에 비례한다는 기본 가정은 보유하고있다. 붕괴시의 공진 주파수의 변화가 큰 경?...

플래시 광분해 시간 해결 전자 전도도 (FP-부 (Trmc))는 그 전하 캐리어 재결합 과정을 조사하기위한 이상적인 도구 만드는 NS-μs의 시간 척도에 광 여기 전하 캐리어의 역학을 모니터링합니다. 박막 반도체의 포토 - 유도 전하 캐리어의 붕괴 메커니즘을 이해하는 광기 전력 장치의 최적화를 포함한 애플리케이션의 범위 키 중요하다. 유도 캐리어 수명은 종종 유도 캐리어 밀도, 여기 파장, 이동성, 트랩 밀도와 트래핑 속도의 함수입니다. 이 논문은 캐리어 동적 종속성 (강도, 파장, 전자 레인지 주파수)와 그 해석의 넓은 범위를 조사하기위한 시간 해결 전자 전도도 (부 (Trmc)) 기술의 다양성을 보여줍니다. Photogenerated 전하들은 이동성 degre에 따라 실수 및 재료의 유전율의 허수 부 모두를 수정할 수<html> 감금 / 현지화 1의 전자. 물질의 도전율 <img alt="방정식" src="/files/ftp_upload/55232/55232eq1.jpg" /> 그 복소 유전율에 비례 <img alt="방정식" src="/files/ftp_upload/55232/55232eq2.jpg" /> 어디에 <img alt="방정식" src="/files/ftp_upload/55232/55232eq3.jpg" /> 마이크로파 전계의 주파수는, <img alt="방정식" src="/files/ftp_upload/55232/55232eq4.jpg" /> 과 <img alt="방정식" src="/files/ftp_upload/55232/55232eq5.jpg" /> 비유 전율의 실수 부이다. 따라서, 도전성의 실수 부분은 비유 전율의 허수 부에 관련되고, 도전율 (이후에, 편광이라고도 함)의 허수 부분이 공진 주파수의 변화와 관련되어있는 동안, 마이크로 웨이브 흡수에 매핑 될 수있다 전자 레인지 필드 1. t는 &quot;&gt; 부 (Trmc)는 다른 기술에 비해 몇 가지 장점을 제공한다. 예를 들어, DC의 광 전도성 측정은 전극 재료의 접촉이 발생. 향상된 재조합 전극 / 재 계면에서 다시 전하 주입이 인터페이스를 통해 합병증의 범위 고통뿐만 여기자와 쌍생 쌍 강화 해리로 인해인가 전압이 측정 된 캐리어 이동 및 수명의 왜곡에 대한 모든 리드. 반면에, 부 (Trmc)는 접점에서 전송 청구에 의한 왜곡없이 사업자의 고유 이동성을 측정하는 무 전극 기술이다 . 캐리어 동역학 프로브로서 마이크로파 전력을 사용하는 중요한 장점은 또한 전하 캐리어 감쇠기구의 감쇠 수명을 모니터로 / 경로는 또한 조사 할 수 있다는 점이다. 부 (Trmc)는 총 이동 3 및 수명을 결정하는데 사용될 수있다유도 전하 캐리어의 시간 4. 이러한 매개 변수는 다음에 직접 트랩 매개 재결합 메카니즘 3,5- 구별하는데 사용될 수있다. 이들 두 개의 경로 감쇠의 의존성 정량적 캐리어 밀도 3, 5, 여기 에너지 / 파장 (5)의 함수로서 분석 될 수있다. 유도 된 캐리어의 위치 파악 / 한정은 (유전율의 실수 부 허수 VS) 분극 5 대 도전성의 붕괴를 비교하여 조사 할 수있다. 또한, 아마도 가장 중요한 부 (Trmc)는 전하 캐리어 감쇠 통로 역할 트랩 상태를 특성화하기 위해 사용될 수있다. 표면 트랩, 예를 들면, 패시베이션 샘플 6 대 패시베이션 비교하여 벌크 트랩 구별 될 수있다. 서브 - 밴드 갭 상태 수직접 서브 밴드 갭 여기 에너지 (5)를 사용하여 조사한다. 트랩 밀도가 부 (Trmc) 용 데이터 (7)를 끼워 맞춤으로써 도출 될 수있다. 나노 튜브 (1), 유기 반도체 (12) 재료를 혼합, 실리콘 (6), (8) 및 이산화 티탄 9, 10과 같은 기존의 박막 반도체 11 나노 입자 : 때문에이 기술의 다양성에 부 (Trmc)를 포함한 다양한 재료를 연구에 적용된 13, 14, 및 하이브리드 광전지 재료 3, 4, 5. 부 (Trmc)를 이용하여 정량적 인 정보를 획득하기 위해, 정확하게 수를 결정할 수 있도록 중요주어진 광 여진 용 광자 흡수. 박막, 나노 입자, 솔루션 및 불투명 한 샘플의 흡수를 정량화하는 방법이 다르기 때문에, 여기에 제시된 샘플 준비 및 교정 기술은 박막 샘플을 위해 특별히 설계되었습니다. 그러나, 제시된 측정 부 (Trmc) 프로토콜은 매우 일반적이다.

<table><tbody><tr><td>Hellmanex III detergent</td><td>Sigma Aldrich&lt;br/&gt; www.sigmaaldrich.com/catalog/product/sial/z805939?lang=en&amp;amp;region=AU</td><td>Z805939</td><td>Corrosive and toxic. See SDS.</td></tr><tr><td>Lead(II) iodide (99%)</td><td>Sigma Aldrich&lt;br/&gt; www.sigmaaldrich.com/catalog/product/aldrich/211168?lang=en&amp;amp;region=AU</td><td>211168</td><td>Toxic. See SDS.</td></tr><tr><td>Anhydrous dimethylformamide (99.8%)</td><td>Sigma Aldrich&lt;br/&gt; www.sigmaaldrich.com/catalog/product/sial/227056?lang=en&amp;amp;region=AU</td><td>227056</td><td>Toxic. See SDS.</td></tr><tr><td>Anhydrous dimethylsulfoxide (99.9%)</td><td>Sigma Aldrich&lt;br/&gt; www.sigmaaldrich.com/catalog/product/sial/276855?lang=en&amp;amp;region=AU</td><td>276855</td><td>Toxic. See SDS.</td></tr><tr><td>Anhydrous 2-Propanol (99.5%)</td><td>Sigma Aldrich&lt;br/&gt; www.sigmaaldrich.com/catalog/product/sial/278475?lang=en&amp;amp;region=AU&amp;amp;gclid=&lt;br/&gt; COnlgPaw780CFQZvvAod17EA4Q</td><td>278475</td><td></td></tr><tr><td>Methylammonium iodide</td><td>Dyesol&lt;br/&gt; www.dyesol.com/products/dsc-materials/perovskite-precursors/methylammonium-iodide.html</td><td>MS101000</td><td>Also sold by Sigma Aldrich</td></tr><tr><td>Poly(methyl methacrylate)</td><td>Sigma Aldrich</td><td>445746</td><td></td></tr><tr><td>Anhydrous chlorobenzene (99.8%)</td><td>Sigma Aldrich&lt;br/&gt; www.sigmaaldrich.com/catalog/product/aldrich/445746?lang=en&amp;amp;region=AU</td><td>284513</td><td>Toxic. See SDS.</td></tr><tr><td>&lt;strong&gt;Equipment&lt;/strong&gt;</td><td>&lt;strong&gt;Company&lt;/strong&gt;</td><td>&lt;strong&gt;Model&lt;/strong&gt;</td><td>&lt;strong&gt;Comments/Description&lt;/strong&gt;</td></tr><tr><td>UV-VIS-NIR spectrophotometer</td><td>Perkin-Elmer&amp;nbsp;</td><td>Lambda 900</td><td></td></tr><tr><td>Profilometer</td><td>Veeco</td><td>Dektak 150</td><td></td></tr><tr><td>Vector Network Analyzer</td><td>Keysight&lt;br/&gt; www.keysight.com/en/pdx-x201927-pn-N9918A/fieldfox-handheld-microwave-analyzer-265-ghz?cc=US&amp;amp;lc=eng</td><td>Fieldfox N9918A</td><td></td></tr><tr><td>Tunable wavelength laser</td><td>Opotek&lt;br/&gt; www.opotek.com/product/opolette-355</td><td>Opolette 355</td><td></td></tr><tr><td>Neutral density filters</td><td>Thorlabs&lt;br/&gt; www.thorlabs.hk/newgrouppage9.cfm?objectgroup_id=3193</td><td>NUK01</td><td></td></tr><tr><td>Power meter</td><td>Thorlabs&lt;br/&gt; www.thorlabs.com/thorproduct.cfm?partnumber=PM100D</td><td>PM100D</td><td></td></tr><tr><td>Power sensor</td><td>Thorlabs&lt;br/&gt; www.thorlabs.com/thorproduct.cfm?partnumber=S401C</td><td>S401C</td><td></td></tr><tr><td>Cavity</td><td>Custom built</td><td></td><td>The cavity used in for this experiment was designed and built in-house.</td></tr></tbody></table>

recombination dynamics in thin-film photovoltaic materials via time-resolved microwave conductivity

구체적 유기 납 할라이드로서 티탄 석 광전지 재료 박막 반도체의 포토 - 유도 전하 캐리어의 재결합의 동력학을 조사하는 방법이 제공된다. 페 로브 스카이 트 막 두께 및 흡수 계수를 처음 프로필 로메 및 UV-VIS 흡수 스펙트럼을 특징으로한다. 레이저 파워와 공동 모두 감도 교정을 상세히 설명한다. 플래시 광분해 시분 전자 전도도 (부 (Trmc)) 실험을 수행하기위한 프로토콜은, 물질의 전도도를 결정하는 비접촉 방법은 제시된다. 마이크로파의 주파수의 함수로서 부 (Trmc)를 수행하여 복소 전도도의 실수 및 허수 성분을 식별하는 처리를 설명한다. 전하 캐리어 역학 (전력 및 파장을 모두 포함) 다른 여자 정권에서 결정된다. 직접 트랩 매개 붕괴 과정을 구분하는 기술을 제시하고 논의한다.결과는 모델과 반도체의 광유도 전하 캐리어의 일반적인 운동 모델을 참조하여 해석됩니다. 설명 된 기술은 유기 및 무기 광전지 재료를 포함하는 나노 입자의 광전자 재료의 넓은 범위에 적용 가능하고, 반도체 박막 / 전도성.

여기에 제시된 대표적인 결과는 250 나노 미터 CH 3 NH 3 PBI 3 박막 시료에서 얻었다. 전도도의 역학 <img alt="방정식" src="/files/ftp_upload/55232/55232eq54.jpg" /> 전하 캐리어의 역학과 관련 될 수있다 <img alt="방정식" src="/files/ftp_upload/55232/55232eq55.jpg" /> 통하다 <img alt="?...

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Recombination Dynamics in Thin-film Photovoltaic Materials via Time-resolved Microwave Conductivity

A Time Resolved Microwave Conductivity technique for investigating direct and trap-mediated recombination dynamics and determining carrier mobilities of thin film semiconductors is presented here.

시간 해결 전자 전도도를 통해 박막 태양 광 재료의 재조합 역학

A method for investigating recombination dynamics of photo-induced charge carriers in thin film semiconductors, specifically in photovoltaic materials ...

recombination-dynamics-thin-film-photovoltaic-materials-via-time

Research

JoVE Journal

Engineering

11.6K 조회수.  ARC Centre of Excellence in Exciton Science. A Time Resolved Microwave Conductivity technique for investigating direct and trap-mediated recombination dynamics and determining carrier mobilities of thin film semiconductors is presented here.

비디오: Recombination Dynamics in Thin-film Photovoltaic Materials via Time-resolved Microwave Conductivity

Concurrent Quantitative Conductivity and Mechanical Properties Measurements of Organic Photovoltaic Materials using AFM

Organic photovoltaic (OPV) materials are inherently inhomogeneous at the nanometer scale. Nanoscale inhomogeneity of OPV materials affects performance of photovoltaic devices. Thus, understanding of spatial variations in composition as well as electrical properties of OPV materials is of paramount importance for moving PV technology forward.1,2 In this paper, we describe a protocol for quantitative measurements of electrical and mechanical properties of OPV materials with sub-100 nm resolution. Currently, materials properties measurements performed using commercially available AFM-based techniques (PeakForce, conductive AFM) generally provide only qualitative information. The values for resistance as well as Young's modulus measured using our method on the prototypical ITO/PEDOT:PSS/P3HT:PC61BM system correspond well with literature data. The P3HT:PC61BM blend separates onto PC61BM-rich and P3HT-rich domains. Mechanical properties of PC61BM-rich and P3HT-rich domains are different, which allows for domain attribution on the surface of the film. Importantly, combining mechanical and electrical data allows for correlation of the domain structure on the surface of the film with electrical properties variation measured through the thickness of the film.

Organic photovoltaic (OPV) materials are inherently inhomogeneous at the nanometer scale. Nanoscale inhomogeneity of OPV materials affects performance of photovoltaic devices. In this paper, we describe a protocol for quantitative measurements of electrical and mechanical properties of OPV materials with sub-100 nm resolution.

동시 수량 전도성과 AFM을 사용하여 유기 태양 광 재료의 기계적 성질 측정

Organic photovoltaic  (OPV) materials are inherently inhomogeneous at the nanometer scale. Nanoscale  inhomogeneity of OPV materials affects performance ...

연구

공학

Measurement of Coherence Decay in GaMnAs Using Femtosecond Four-wave Mixing

The application of femtosecond four-wave mixing to the study of fundamental properties of diluted magnetic semiconductors ((s,p)-d hybridization, spin-flip scattering) is described, using experiments on GaMnAs as a prototype III-Mn-V system.&#160; Spectrally-resolved and time-resolved experimental configurations are described, including the use of zero-background autocorrelation techniques for pulse optimization.&#160; The etching process used to prepare GaMnAs samples for four-wave mixing experiments is also highlighted.&#160; The high temporal resolution of this technique, afforded by the use of short (20 fsec) optical pulses, permits the rapid spin-flip scattering process in this system to be studied directly in the time domain, providing new insight into the strong exchange coupling responsible for carrier-mediated ferromagnetism.&#160; We also show that spectral resolution of the four-wave mixing signal allows one to extract clear signatures of (s,p)-d hybridization in this system, unlike linear spectroscopy techniques.&#160;&#160; This increased sensitivity is due to the nonlinearity of the technique, which suppresses defect-related contributions to the optical response. This method may be used to measure the time scale for coherence decay (tied to the fastest scattering processes) in a wide variety of semiconductor systems of interest for next generation electronics and optoelectronics.

The technique of femtosecond four-wave mixing is described, including spectrally-resolved and time-resolved configurations. We illustrate the utility of this technique for the investigation of crucial physical properties in the III-V diluted magnetic semiconductors, afforded by its nonlinearity and high temporal resolution.

The application of femtosecond four-wave mixing to the study of fundamental properties of diluted magnetic semiconductors ((s,p)-d hybridization, ...

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 ...

Using Microwave and Macroscopic Samples of Dielectric Solids to Study the Photonic Properties of Disordered Photonic Bandgap Materials

Recently, disordered photonic materials have been suggested as an alternative to periodic crystals for the formation of a complete photonic bandgap (PBG). In this article we will describe the methods for constructing and characterizing macroscopic disordered photonic structures using microwaves. The microwave regime offers the most convenient experimental sample size to build and test PBG media. Easily manipulated dielectric lattice components extend flexibility in building various 2D structures on top of pre-printed plastic templates. Once built, the structures could be quickly modified with point and line defects to make freeform waveguides and filters. Testing is done using a widely available Vector Network Analyzer and pairs of microwave horn antennas. Due to the scale invariance property of electromagnetic fields, the results we obtained in the microwave region can be directly applied to infrared and optical regions. Our approach is simple but delivers exciting new insight into the nature of light and disordered matter interaction.

Our representative results include the first experimental demonstration of the existence of a complete and isotropic PBG in a two-dimensional (2D) hyperuniform disordered dielectric structure. Additionally we demonstrate experimentally the ability of this novel photonic structure to guide electromagnetic waves (EM) through freeform waveguides of arbitrary shape.

Disordered structures offer new mechanisms for forming photonic bandgaps and unprecedented freedom in functional-defect designs. To circumvent the computational challenges of disordered systems, we construct modular macroscopic samples of the new class of PBG materials and use microwaves to characterize their scale-invariant photonic properties, in an easy and inexpensive manner.

무질서 광 밴드 갭 (photonic bandgap) 재료의 광자 속성을 연구에 전자 레인지 및 유전체 고체의 육안 샘플을 사용하여

Recently, disordered photonic materials have been suggested as an alternative to periodic crystals for the formation of a complete photonic bandgap (PBG). ...

Making Record-efficiency SnS Solar Cells by Thermal Evaporation and Atomic Layer Deposition

Tin sulfide (SnS) is a candidate absorber material for Earth-abundant, non-toxic solar cells. SnS offers easy phase control and rapid growth by congruent thermal evaporation, and it absorbs visible light strongly. However, for a long time the record power conversion efficiency of SnS solar cells remained below 2%. Recently we demonstrated new certified record efficiencies of 4.36% using SnS deposited by atomic layer deposition, and 3.88% using thermal evaporation. Here the fabrication procedure for these record solar cells is described, and the statistical distribution of the fabrication process is reported. The standard deviation of efficiency measured on a single substrate is typically over 0.5%. All steps including substrate selection and cleaning, Mo sputtering for the rear contact (cathode), SnS deposition, annealing, surface passivation, Zn(O,S) buffer layer selection and deposition, transparent conductor (anode) deposition, and metallization are described. On each substrate we fabricate 11 individual devices, each with active area 0.25 cm2. Further, a system for high throughput measurements of current-voltage curves under simulated solar light, and external quantum efficiency measurement with variable light bias is described. With this system we are able to measure full data sets on all 11 devices in an automated manner and in minimal time. These results illustrate the value of studying large sample sets, rather than focusing narrowly on the highest performing devices. Large data sets help us to distinguish and remedy individual loss mechanisms affecting our devices.

Tin sulfide (SnS) is a candidate material for Earth-abundant, non-toxic solar cells. Here, we demonstrate the fabrication procedure of the SnS solar cells employing atomic layer deposition, which yields 4.36% certified power conversion efficiency, and thermal evaporation which yields 3.88%.

열 증발 및 원자 층 증착에 의해 기록 효율 SNS 태양 전지 만들기

Tin sulfide (SnS) is a candidate absorber material for Earth-abundant, non-toxic solar cells. SnS offers easy phase control and rapid growth by congruent ...

Comprehensive Characterization of Extended Defects in Semiconductor Materials by a Scanning Electron Microscope

Extended defects such as dislocations and grain boundaries have a strong influence on the performance of microelectronic devices and on other applications of semiconductor materials. However, it is still under debate how the defect structure determines the band structure, and therefore, the recombination behavior of electron-hole pairs responsible for the optical and electrical properties of the extended defects. The present paper is a survey of procedures for the spatially resolved investigation of structural and of physical properties of extended defects in semiconductor materials with a scanning electron microscope (SEM). Representative examples are given for crystalline silicon. The luminescence behavior of extended defects can be investigated by cathodoluminescence (CL) measurements. They are particularly valuable because spectrally and spatially resolved information can be obtained simultaneously. For silicon, with an indirect electronic band structure, CL measurements should be carried out at low temperatures down to 5 K due to the low fraction of radiative recombination processes in comparison to non-radiative transitions at room temperature. For the study of the electrical properties of extended defects, the electron beam induced current (EBIC) technique can be applied. The EBIC image reflects the local distribution of defects due to the increased charge-carrier recombination in their vicinity. The procedure for EBIC investigations is described for measurements at room temperature and at low temperatures. Internal strain fields arising from extended defects can be determined quantitatively by cross-correlation electron backscatter diffraction (ccEBSD). This method is challenging because of the necessary preparation of the sample surface and because of the quality of the diffraction patterns which are recorded during the mapping of the sample. The spatial resolution of the three experimental techniques is compared.

The optical, electrical, and structural properties of dislocations and of grain boundaries in semiconductor materials can be determined by experiments performed in a scanning electron microscope. Electron microscopy has been used to investigate cathodoluminescence, electron beam induced current, and diffraction of backscattered electrons.

Extended defects such as dislocations and grain boundaries have a strong influence on the performance of microelectronic devices and on other applications ...

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

Novel Techniques for Observing Structural Dynamics of Photoresponsive Liquid Crystals

We discuss in this article the experimental measurements of the molecules in liquid crystal (LC) phase using the time-resolved infrared (IR) vibrational spectroscopy and time-resolved electron diffraction. Liquid crystal phase is an important state of matter that exists between the solid and liquid phases and it is common in natural systems as well as in organic electronics. Liquid crystals are orientationally ordered but loosely packed, and therefore, the internal conformations and alignments of the molecular components of LCs can be modified by external stimuli. Although advanced time-resolved diffraction techniques have revealed picosecond-scale molecular dynamics of single crystals and polycrystals, direct observations of packing structures and ultrafast dynamics of soft materials have been hampered by blurry diffraction patterns. Here, we report time-resolved IR vibrational spectroscopy and electron diffractometry to acquire ultrafast snapshots of a columnar LC material bearing a photoactive core moiety. Differential-detection analyses of the combination of time-resolved IR vibrational spectroscopy and electron diffraction are powerful tools for characterizing structures and photoinduced dynamics of soft materials.

Here, we present the protocols of differential-detection analyses of time-resolved infrared vibrational spectroscopy and electron diffraction which enable observations of the deformations of local structures around photoexcited molecules in a columnar liquid crystal, giving an atomic perspective on the relationship between the structure and the dynamics of this photoactive material.

Photoresponsive 액정의 구조 역학을 관찰을 위한 새로운 기술

We discuss in this article the experimental measurements of the molecules in liquid crystal (LC) phase using the time-resolved infrared (IR) vibrational ...

Carrier Lifetime Measurements in Semiconductors through the Microwave Photoconductivity Decay Method

This work presents a protocol employing the microwave photoconductivity decay (&#956;-PCD) for measurement of the carrier lifetime in semiconductor materials, especially SiC. In principle, excess carriers in the semiconductor generated via excitation recombine with time and, subsequently, return to the equilibrium state. The time constant of this recombination is known as the carrier lifetime, an important parameter in semiconductor materials and devices that requires a noncontact and nondestructive measurement ideally achieved by the &#956;-PCD. During irradiation of a sample, a part of the microwave is reflected by the semiconductor sample. Microwave reflectance depends on the sample conductivity, which is attributed to the carriers. Therefore, the time decay of excess carriers can be observed through detection of the reflected microwave intensity, whose decay curve can be analyzed for estimation of the carrier lifetime. Results confirm the suitability of the &#956;-PCD protocol in measuring the carrier lifetime in semiconductor materials and devices.

As one of the important physical parameters in semiconductors, carrier lifetime is measured herein via a protocol employing the microwave photoconductivity decay method.

This work presents a protocol employing the microwave photoconductivity decay (&#956;-PCD) for measurement of the carrier lifetime in semiconductor ...