2016 IEEE 43rd Photovoltaic Specialists Conference (PVSC)最新文献

{"title":"Utilization of Tabula Rasa to stabilize bulk lifetimes in n-Cz silicon for high-performance solar cell processing","authors":"V. LaSalvia, M. Jensen, A. Youssef, W. Nemeth, M. Page, T. Buonassisi, P. Stradins","doi":"10.1109/PVSC.2016.7749771","DOIUrl":"https://doi.org/10.1109/PVSC.2016.7749771","url":null,"abstract":"We investigate a high temperature, high cooling-rate anneal Tabula Rasa (TR) and report its implications on n-type Czochralski-grown silicon (n-Cz Si) for photovoltaic fabrication. Tabula Rasa aims at dissolving and homogenizing oxygen precipitate nuclei that can grow during the cell process steps and degrade the cell performance due to their high internal gettering and recombination activity. The Tabula Rasa thermal treatment is performed in a clean tube furnace with cooling rates >100°C/s. We characterize the bulk lifetime by Sinton lifetime and photoluminescence mapping just after Tabula Rasa, and after the subsequent cell processing. After TR, the bulk lifetime surprisingly degrades to <; 0.1ms, only to recover to values equal or higher than the initial non-treated wafer (several ms), after typical high temperature cell process steps. Those include boron diffusion and oxidation; phosphorus diffusion/oxidation; ambient annealing at 850°C; and crystallization annealing of tunneling-passivating contacts (doped polycrystalline silicon on 1.5 nm thermal oxide). The drastic lifetime improvement during high temperature cell processing is attributed to improved external gettering of metal impurities and annealing of intrinsic point defects. Time and injection dependent lifetime spectroscopy further reveals the mechanisms of lifetime improvement after Tabula Rasa treatment. Additionally, we report the efficacy of Tabula Rasa on n-type Cz-Si wafers and its dependence on oxygen concentration, correlated to position within the ingot.","PeriodicalId":6524,"journal":{"name":"2016 IEEE 43rd Photovoltaic Specialists Conference (PVSC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81513867","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Arc generator for photovoltaic arc fault detector testing","authors":"P. C. Hatton, Mohammed Bathaniah, Zhan Wang, R. Balog","doi":"10.1109/PVSC.2016.7749914","DOIUrl":"https://doi.org/10.1109/PVSC.2016.7749914","url":null,"abstract":"Arcing in photovoltaic (PV) power systems is a significant concern due to the potential for property damage from a PV system fire and personal safety from electrical shock hazard or electrocution if an arc is undetected and left unmitigated. Arc fault detectors are now required by the National Electric Code and Underwriters Laboratories (UL) standard 1699B is currently under development to address testing and listing requirements for these devices. One significant challenge that arose in UL1699B draft standard development process was the way in which an arc was created to test the arc fault detector, i.e. how is an arc generated that faithfully replicates real-world conditions yet can be done with high repeatability in the laboratory? While UL standards, test protocols, and test beds exist for AC-system arc fault detectors, arcs in DC systems, particularly PV, are different. This paper reports on the results of a project to develop a DC arc generator (AG) suitable for use in the development and testing of DC arc fault detectors.","PeriodicalId":6524,"journal":{"name":"2016 IEEE 43rd Photovoltaic Specialists Conference (PVSC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83863342","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of different electron and holes effective masses, temperatures and electrochemical potentials on the hot carrier solar cell efficiency","authors":"F. Gibelli, J. Guillemoles","doi":"10.1109/PVSC.2016.7749769","DOIUrl":"https://doi.org/10.1109/PVSC.2016.7749769","url":null,"abstract":"Third generation hot carrier solar cells could achieve very high conversion yield at reasonable cost. Different theoretical approaches have been used to model these devices and to determine the maximal achivable efficiency, by taking into account different working conditions as well as different losses. However, the uncertainty about the kind of the carrier which heats has led to consider in the different models that both electrons and holes were at a same hot temperature. Here we revisit the theoretical work about hot carriers in order to take into account two different hot temperatures, one for each type of carrier (electron or hole). Then we use this theoretical approach to model the hot carrier solar cell performance with different electron and hole thermodynamical properties.","PeriodicalId":6524,"journal":{"name":"2016 IEEE 43rd Photovoltaic Specialists Conference (PVSC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77749515","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The purpose of a photon ratchet in intermediate band solar cells","authors":"Andreas Pusch, M. Yoshida, N. P. Hylton, A. Mellor, Anthony Vaquero-Steiner, C. Phillips, O. Hess, N. Ekins‐Daukes","doi":"10.1109/PVSC.2016.7749398","DOIUrl":"https://doi.org/10.1109/PVSC.2016.7749398","url":null,"abstract":"The intermediate band solar cell (IBSC) concept aims to improve upon the Shockley-Queisser limit for single bandgap solar cells by also making use of below bandgap photons through sequential absorption processes via an intermediate band (IB). In order for this concept to be translated into more efficient solar cells there are still challenges to overcome; one of the most important is the increased recombination (radiative as well as non-radiative) associated with the additional states in the bandgap. A proposal to mitigate those recombination losses is the introduction of a photon ratchet into the IBSC, which effectively trades some of the energy of the excited electrons against these recombination losses. We show here that this can lead to substantial improvements even in the radiative limiting efficiency, where no non-radiative recombination is taken into account and that this advantage is especially prominent for IBSCs in which the transitions into and out of the IB are not very absorptive, a case commonly encountered for current IBSC proposals.","PeriodicalId":6524,"journal":{"name":"2016 IEEE 43rd Photovoltaic Specialists Conference (PVSC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82574320","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Synchrotron x-ray characterization of alkali elements at grain boundaries in Cu(In, Ga)Se2 solar cells","authors":"B. West, M. Stuckelberger, H. Guthrey, Lei Chen, B. Lai, J. Maser, V. Rose, J. Dynes, W. Shafarman, M. Al‐Jassim, M. Bertoni","doi":"10.1109/PVSC.2016.7749403","DOIUrl":"https://doi.org/10.1109/PVSC.2016.7749403","url":null,"abstract":"It is well known that the addition of alkali elements such as Na and K during and after growth of Cu(In, Ga)Se2 (CIGS) has beneficial effects on the electronic properties of bulk material, improving device performance significantly. While the device level effects have been measured and reported, a direct observations of the localization of Na including its chemical nature are missing, and the impact of Na on elemental and phase segregation during CIGS growth is not fully understood. We investigate these aspects to shine light on the role of Na in CIGS solar cells with the ultimate goal of increasing their conversion efficiency. Utilizing a suite of synchrotron based x-ray characterization techniques, we discuss the challenges and advantages of these techniques for investigating segregation of main constituents of CIGS, Na distribution, chemical bonding of Na, and collection efficiency in CIGS as well as their correlations.","PeriodicalId":6524,"journal":{"name":"2016 IEEE 43rd Photovoltaic Specialists Conference (PVSC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89756097","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Current leakage and fill factor in multi-junction solar cells linked via absolute electroluminescence characterization","authors":"Lin Zhu, M. Yoshita, Tetsuya Nakamura, T. Mochizuki, Changsu Kim, M. Imaizumi, Y. Kanemitsu, H. Akiyama","doi":"10.1109/PVSC.2016.7749812","DOIUrl":"https://doi.org/10.1109/PVSC.2016.7749812","url":null,"abstract":"Direct link between current-leakage features and fill factors was demonstrated in GaInP/GaAs 2-junction solar cells via combining measurements of absolute electroluminescence (EL) intensity and EL imaging. The drops of subcell external radiative efficiency under low injection level have shown large differences among the solar cells fabricated in the same batch, which lead to the difference in the fill factor (FF) and performance of the cells under illumination. The absolute EL images clearly revealed that a current leakage, instead of higher non-radiative recombination rates, in the GaAs-subcell caused the significant degradation in its ηext at low injection current and in the lower FF. The absolute EL provides a powerful way to diagnose FF in addition to open-circuit voltage of individual subcells in MJ solar cells.","PeriodicalId":6524,"journal":{"name":"2016 IEEE 43rd Photovoltaic Specialists Conference (PVSC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74843657","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhanced surface passivation of epitaxially grown emitters for high-efficiency ultrathin crystalline Si solar cells","authors":"W. Yoon, Anthony Lochtefeld, N. Kotulak, D. Scheiman, A. Barnett, P. Jenkins, R. Walters","doi":"10.1109/PVSC.2016.7750215","DOIUrl":"https://doi.org/10.1109/PVSC.2016.7750215","url":null,"abstract":"In this work, we demonstrated an enhanced surface passivation of epitaxially grown boron-doped emitters by replacing thermal SiO₂ as a passivation layer of p⁺-emitter employed in a 16.8% efficient 18-μm Si solar cell on stainless steel with plasma assisted atomic layer deposition (ALD) Al₂O₃/PECVD SiN_x stack. For the Al₂O₃/SiN_x stacks on epitaxial p⁺-emitter after post-deposition anneal, the emitter saturation current density (J_0e) values were decreased to 19.5 fA/cm² with the corresponding iV_oc of 688 mV By using advanced surface passivation scheme, further improvement in the V_oc of a present 16.8% efficient ultrathin Si solar cell on steel can be expected.","PeriodicalId":6524,"journal":{"name":"2016 IEEE 43rd Photovoltaic Specialists Conference (PVSC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79024966","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Biomonitoring of CdTe PV manufacturing and recycling workers","authors":"P. Sinha, M. Fischman, Jim Campbell, G. C. Lee, Lein Sim Lim","doi":"10.1109/PVSC.2016.7750341","DOIUrl":"https://doi.org/10.1109/PVSC.2016.7750341","url":null,"abstract":"Biomonitoring data from nearly 3,000 workers over a five year period (2009-2014) from First Solar's CdTe photovoltaics manufacturing and recycling facility in Malaysia were evaluated to determine longitudinal trends in the body burden of Cd in workers. Biomonitoring data consisted of baseline and periodic sampling of blood and urine Cd, with workers grouped according to gender, smoking status, and potential occupational exposure risk to Cd compounds. Average worker blood and urine Cd concentrations were below occupational biological limits and background values, and show a statistically significant decreasing trend as a function of years worked for non-smokers. For smokers, smoking is the predominant factor affecting blood Cd results among First Solar Malaysia workers.","PeriodicalId":6524,"journal":{"name":"2016 IEEE 43rd Photovoltaic Specialists Conference (PVSC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80829394","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of triethanolamine on the formation of CZTS films using a simple dip coating technique","authors":"S. Chaudhari, P. Kannan, S. Dey","doi":"10.1109/PVSC.2016.7749852","DOIUrl":"https://doi.org/10.1109/PVSC.2016.7749852","url":null,"abstract":"CZTS films are deposited through a non-hydrazine precursor solution (with and without Triethanolamine, a stabilizing agent) by dip coating technique followed by annealing in various atmosphere. Phase formation of CZTS films as well as mechanism behind reduction of voids and porosity in the film in presence of stabilizing agent is investigated. X-Ray diffraction pattern and Raman spectra revealed the formation of kesterite structure of CZTS. SEM micrograph of CZTS film using TEA as a stabilizing agent confirms the formation of smooth, less porous, more uniform and compact film.","PeriodicalId":6524,"journal":{"name":"2016 IEEE 43rd Photovoltaic Specialists Conference (PVSC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80009230","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Power variability of small scale PV systems caused by shading from passing clouds in tropical region","authors":"L. Jiang, D. Maskell, R. Srivatsan, Qing Xu","doi":"10.1109/PVSC.2016.7750248","DOIUrl":"https://doi.org/10.1109/PVSC.2016.7750248","url":null,"abstract":"Due to the nonlinear characteristics of the photovoltaic (PV) cell and of the bypass diode used to mitigate against hot spots, not only the amplitude of the irradiance can influence the power output but also the irradiance distribution. For a small to medium PV installation, the power output could be significantly influenced when clouds pass over a solar power installation and temporarily block the incoming radiation from sun. Especially in tropical regions, shading events caused by passing clouds are significantly common. This paper examines the power variability of the small scale PV installations caused by the impact of passing clouds in tropical regions. An array of 16 irradiance sensors (4 by 4), which collect data at 1-second intervals, the irradiance difference between individual sensors in the sensor array is investigated. Three typical weather conditions, namely overcast, clear and cloudy, are tested in the experiment, with cloudy days producing many large irradiance change events resulting in significant variations among the sensors. The two diode model is used to model the PV array and its parameters are identified using an improved differential evolution algorithm. This method provides good accuracy of the PV array model. After applying the measured irradiance and temperature data to the PV array model, the average power variabilities of a series of polycrystalline and CIGS thin film PV panels are studied. The results show that for polycrystalline PV systems the average power variability caused by the shading effect of passing clouds in overcast, clear and cloudy days can reach 2.84%, 4.49% and 6.71%, respectively, for a 10 hour period, while for CIGS thin film PV system 1.69%, 4.19% and 5.61%, respectively. The results also show that for the tested systems polycrystalline PV arrays are more vulnerable to the variable irradiance conditions. We plan to use this data to develop strategies for the design of PV power plants, to mitigate against the shading effect caused by passing clouds in tropical regions.","PeriodicalId":6524,"journal":{"name":"2016 IEEE 43rd Photovoltaic Specialists Conference (PVSC)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77999221","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}