Public Research Seminars

Research Seminars are open to the public and are run on Thursdays.

Next Seminar Location:  UNSW Building H6 – Tyree Energy Technologies Building -  G17

Time: 12pm - 1pm

*** NEW*** Professor Martin Green's Video Presentation 2012 SEMI Roadmap for Photovoltaics: Bigger, Thinner, Faster, Cheaper Click HERE to view

Prior Seminars

10 May 2012

Presentation of INES, the French National Institute for Solar Energy: overview of the wide R&D range: from solar grade to sustainable building and electric cars.

Dr. Francoise Burgun

Presentation of INES, the French National Institute for Solar Energy: overview of the wide R&D range, from solar grade to sustainable building and electric cars.

INES is the first French and one of the first European centres dedicated to research, innovation and training on solar energy. Set up with the backing of the French Government, the Regional Council and staffed by teams from the CEA (Atomic Energy and Alternative Energy Commission), the CNRS (National Centre for Scientific Research), and the University of Savoie, it gathers today more than 350 people from different backgrounds and by the year 2015 will bring together more than 500 people onsite 20,000 sqm.

INES is a young institute as it began to take shape in 2005 and was officially launched in July 2006. Still its achievements are remarkable through the implementation of a wild range of technological platforms, as well as its capacity to attract high qualified and experienced engineers and researchers and its ability to launch many academic and industrial research programs on a national and international level.

The CEA staffs of INES – DTS, Department for Solar Energy - count more than 300 employees and therefore constitute the main task force for INES Research and Innovation activities. They cover the fields of solar thermal, photovoltaic, energy storage and their application to the domain of energy, building and electric car. DTS’s research work covers complete technological processes, from basic components to prototypes integrated into a system for the purposes of demonstration. Its approach to research takes into account the need for quick turn-around times and constraints on industrial costs.

Moreover, DTS is part of the LITEN, the Laboratory for Innovation in New Energy Technologies and Nanomaterials of CEA, which is one of Europe’s newest and most important research centres in the energy technology field. Hence, DTS strengthens its capacity trough access to latest LITEN’s advanced researches on materials and energy managemen

26 April 2012

Classification and Investigation of Recombination Active Defects in Multicrystalline Silicon Solar Cells

Dominik Lausch

All multicrystalline silicon (mc-Si) solar cells suffer from recombination active defect structures. Recombination active defects in solar cells made from pure as well as from upgraded metallurgical grade Si feedstock are limiting the solar efficiency and electrical breakdown behaviour. Therefore it is of utmost importance to understand the cause and the physical mechanism of recombination and pre-breakdown processes at these defects. Since a mc-Si solar cell has a large number of defects it is mandatory to classify the different defect before investigation. In this seminar a classification of recombination active defects in mc-Si solar cells based on previous studies is presented. Two types of recombination active defects can be clearly distinguished already on a macroscopic scale. For a more detailed understanding the classification was also performed on microscopic scale. It is shown that defect types observed on a macroscopic scale could also be directly related to structures on a microscopic scale; however, a third defect type had to be introduced. The microscopic investigations allow us to establish an exact relation of electrical, structural and chemical information. One defect type could be clearly correlated to metal precipitates located at defect structures of the underlying wafer explaining additionally the observed pre-breakdown behaviour at these defect structures. It is also shown that this defect type is strongly influenced by the solar cell process. Based on these results a model for the different classified types will be proposed explaining the observed recombination and pre-breakdown behaviour. The knowledge obtained can be reversibly interconnected to the macroscopic investigation on an industrial level to work on a solution to avoid these problems.

19 April 2012

2012 SEMI Roadmap for Photovoltaics: Bigger, Thinner, Faster, Cheaper

Scientia Professor Martin Green

Industry roadmaps have played a major role in the microelectronics industry in focussing manufacturers, researchers and equipment suppliers on common targets for future technology development. In 2010, the first roadmap for the photovoltaics industry was published, with a major update published recently at the end of March 2012. The key features of the new roadmap will be described. Particularly interesting are variations from the previous 2011 roadmap as these indicate refinements in thinking about the future of the industry based on the very rapid progress over the last year.

BRIEF BIOGRAPHY

Martin Green is currently a Scientia Professor at the University of New South Wales, Sydney, Australia and Executive Research Director of the University's Photovoltaic Centre of Excellence. His group's contributions to photovoltaics include development of the world’s highest efficiency silicon solar cells and commercialization of several different cell technologies.  He is the author of several well known books on solar cells and numerous papers.  His work has resulted in many major international awards including the 2002 Right Livelihood Award, commonly known as the Alternative Nobel Prize, the 2007 SolarWorld Einstein Award and the 2009 ENI Award for Renewable and Non Conventional Energy.

12 April 2012

Harvesting Solar Energy Using Nanofluids-Based Concentrating Solar Collection

Dr. Himanshu Tyagi

Conventional concentrated solar thermal collectors harness solar energy through several steps of heat transfer. The incident solar radiations are usually directly absorbed by a solid surface (either flat, in the case of a flat-plate type solar collector - or curved, in the case of parabolic trough collectors). These surfaces in turn can transfer the thermal energy to a fluid which may then be used for various applications such as for process heating, chemical processing, electricity generation etc. For some years now, research work has been going on to make the heat transfer process more efficient primarily by reducing the heat losses from a solar collector. One unique way this can be achieved is by employing the concept of direct absorption where a significant portion of the sunlight is directly absorbed by the fluid itself - thereby eliminating one big step of heat transfer.

In order to achieve direct absorption, trace amounts of nanoparticles may be added to the base-fluid which is shown to have significant impact on the optical as well as thermo-physical properties of the base fluid. Enhancement of thermal conductivity and absorption capacity of the base fluid scales up the heat transfer rate.  This results in higher & more efficiency heat transfer. Preliminary results have shown that while maintaining the same external conditions (such as ambient/initial temperatures, wind speed, solar insolation, flow rate, concentration ratio etc.) the nanofluid-based parabolic concentrating solar collector has about 5-15% higher efficiency as compared to the conventional parabolic solar collector.

BRIEF BIOGRAPHY 

Himanshu Tyagi is currently working as Assistant Professor in the School of Mechanical, Materials & Energy Engineering at Indian Institute of Technology (IIT) Ropar. He has previously worked in the Steam Turbine Design Division of Siemens (in Germany & India) and in the Thermal & Fluids Core Competency group of Intel (in USA). He did his PhD from Arizona State University in the field of heat transfer, and specifically looked at the radiative & ignition properties of nanofluids. He and his co-workers proposed the concept of direct absorption solar collectors using nanofluids which won the Best paper award at the ASME Energy Sustainability Conference at Long Beach, CA. Prior to his PhD he obtained his masters from University of Windsor, Canada and his bachelors from IIT Delhi both in Mechanical Engineering. At present he is working to develop clean and sustainable energy sources with a team of three graduate students and four undergraduates.

5 April 2012

VALUE OF PHOTOVOLTAIC SOLAR CELL EFFICIENCY TO ACHIEVE LOW COST SOLAR ELECTRICITY

Professor Allen Barnett

The levelized cost of energy (LCOE) is used to compare different energy generation technologies or systems. The relatively high LCOE of photovoltaics (PV) can be an obstacle to adopting it as a significant electricity source for terrestrial applications. In a conventional PV system, the cost of the module contributes approximately half of the expense and the other costs are together summarized as balance of system (BOS). A large portion of the BOS is not related to the peak power of the system, but can be either proportional to or independent of the total installation area. Across different PV systems with the same installation area, this part of BOS ($/W) is directly dependent on the module efficiency. Therefore, the LCOE is affected by the module efficiency even if the module price ($/W) remains the same. In this paper, the LCOE across PV systems with equal installation areas but with modules of different efficiencies installed with fixed tilt, 1-axis tracking or 2-axis tracking are compared. It is concluded that at a given module price in $/W, more efficient PV modules lead to lower LCOE systems.  Two examples of new high efficiency solar cell modules; thin crystalline silicon (20+%) and tandem solar cells on silicon (30+%) will be presented.

BRIEF BIOGRAPHY

Allen Barnett joined the School of Photovoltaics and Renewable Energy Engineering, The University of New South Wales, Sydney NSW 2052 Australia as Professor of Advanced Photovoltaics in September 2011. At UNSW his research is focused on new high efficiency solar cell modules; thin crystalline silicon (20+%) and tandem solar cells on silicon (30+%). He joined the University of Delaware in 1976 as Director of the Institute of Energy Conversion and Professor of Electrical Engineering. He left UD in 1993 to devote full time to AstroPower, Inc, which became the largest independent solar cell manufacturer and the 4th largest in the World. He returned ot UD in 2003 and was Executive Director, Solar Power Program; Research Professor, Department of Electrical and Computer Engineering; and Senior Policy Fellow, Center for Energy and Environmental Policy at the University of Delaware, Newark Delaware.  Barnett has supervised 26 Ph.D. theses including 7 Ph.D.s and 3 M.S. degrees in 2011.  

Barnett received his M.S. and B.S. in Electrical Engineering from the University of Illinois, and his Ph. D. in Electrical Engineering from Carnegie-Mellon University. He is a Fellow of the Institute of Electrical and Electronic Engineers (IEEE). He received the IEEE William R. Cherry Award for outstanding contributions to the advancement of photovoltaic science and technology and the Karl W. Böer Solar Energy Medal of Merit.  He is on committees for the two largest photovoltaic conferences.  He has more than 280 publications, 28 U.S. patents, and 7 R&D 100 Awards for new industrial products.  He actively consults for government agencies, institutional investors, and private companies. He was named one of “The 50 Most Influential Delawareans (State of Delaware) of the Past 50 Years” in 2012

29 March 2012

TUV Rheinland Japan – Experience through global growth of the PV Industry and the role of Quality Assurance in enabling development of Solar Energy.

Nick Morley

TUV Rheinland, with the largest global network of PV testing laboratories and over 30 years of experience in the field of photovoltaics, has been assisting the PV industry on its path to becoming a major contributor to the world energy mix. Solar photovoltaic power has become an economical and attractive energy form within this energy mix, while manufacturers try to maintain strong positions facing an increasingly competitive market.

After the March 11 earthquake over 40 nuclear power stations were disconnected from the grid due to safety concerns. In order to address this energy supply problem the Japanese government has redesigned its energy policy and plans to introduce a strong feed-in-tariff for PV within this year which will also support large mega-solar installations. With such potential for growth, quality assurance and 3^rd party testing has never been more important in order to ensure the confidence of investors and the public in photovoltaic energy. With our master solar testing laboratories for the Asia/Pacific region, TUV Rheinland Japan is in a key position to help enable safe and reliable roll-out of photovoltaics at a large scale.

This seminar will introduce testing and evaluation procedures for photovoltaic modules while describing general operations of TUV Rheinland as a group, with particular insights into our Japan photovoltaic testing laboratories where several UNSW students have participated in our internship program!

Nick Morley, BE RE Eng, Honours Class 1
Project Engineer
Solar Technology
TUV Rheinland Japan

22 March 2012

Hot Carriers Solar Cells:
Recent developments and future challenges

Pasquale Aliberti

The hot carrier solar cell is a third generation photovoltaic device that can potentially achieve a conversion efficiency well above the Shockley-Queisser limit by limiting heat loss, which is the main cause for the limited efficiency of conventional solar cells. This can be accomplished by extracting highly energetic (hot) carriers from the absorber layer of the device before they thermalise by losing their excess energy to the absorber lattice as heat. Although the basic operating principle of a hot carrier solar cell is rather simple, the actual design and realization of the device presents complex theoretical and technological challenges.

This seminar has the aim of giving an overview of current research on hot carrier solar cells, presenting recent achievements and future challenges that need to be addressed in order to move towards the realization of a device. Furthermore, results of theoretical and experimental work on practical hot carrier solar cell structures performed at UNSW will be presented and discussed.

8 March 2012

Diode Laser Processing of Si Thin Film Solar Cells

Bonne Eggleston

This seminar presents three new processes utilising a fast, large area cw diode laser to improve the efficiency and reduce the cost of silicon thin-film solar cells made on glass substrates. 

The first is a defect annealing process which replaces a belt furnace anneal for the removal of crystallographic defects and activation of dopants in solid-phase crystallised silicon. The highest substrate temperature required during the process sequence is reduced from 960C to 620C, which opens the door to the use of cheaper glass substrates. A peak 1-sun voltage of 492mV is achieved on planar samples, which is an improvement of 32mV over the belt furnace process. 

The films are shown to be partly recrystallised during the process, significantly improving the material quality of the melted section while retaining the dopant profile within the un-melted section.

Completed devices are shown to match the performance of the optimised belt furnace process. 

The second is a complete laser crystallisation process applied to thick a-Si films. Here the film is molten across the entire thickness, and a regime is found whereby long linear grains are formed by continuous growth with the previous crystallised region acting as a seed for thenewly crystallising material. 

Grains up to millimetres in length and hundreds of microns in width have been grown with virtually zero detectable intra-grain defects.

A rear diffused emitter is used to create a pn junction, which produces  voltages as high as 539mV so far.

 IQE measurements show that the glass-side of the films is very well passivated and that the diffusion length is much longer than the device thickness. 

Cells up to 7.8% efficiency have so far been demonstrated without light trapping or optimisation of many of the key processes. 

The third new process is large area solid-state diffusion using a diode laser to drive in spin-on dopants. 

This process has been used to form a junction and demonstrated some of the highest voltages on the diode laser crystallised silicon and to form a back surface field for solid-phase crystallised cells

23 Feb 2012

20% Double-sided Laser-doped Cells on Standard
Commercial Grade P-type Silicon

Adeline Sugianto

This seminar presents the development of a novel next-generation Laser-doped Selective Emitter (LDSE) cell structure that focuses on improving the rear surface design while retaining the excellent front surface design of the LDSE cell. This cell structure employs a commercially-manufacturable dielectric layer for rear surface passivation; and relies on the use of boron laser doping in conjunction with sputtered Al for localised rear contact formation. Test structures with an implied V_oc over 700 mV (prior to laser doping) indicates high surface-passivation quality given by the dielectric layer following thermal anneal. Demonstration of sheet resistance as low as 5 W/ on the boron laser-doped p⁺ regions highlights the potential for low-temperature Al sintering to form an ohmic contact. Different geometries for the rear contact pattern are designed and implemented to establish optimum current collection. By improving the rear surface design, cells with independently-confirmed cell efficiencies as high as 20% are achieved on large area, standard commercial-grade p-type wafers, with the potential for further efficiency increase exceeding 21%. These results suggest that this new-generation of LDSE cells have the potential of becoming an industrially-applicable cell technology in the PV industry.