Navigation Links
Special coating greatly improves solar cell performance

The energy from sunlight falling on only 9 percent of Californias Mojave Desert could power all of the United States electricity needs if the energy could be efficiently harvested, according to some estimates. Unfortunately, current-generation solar cell technologies are too expensive and inefficient for wide-scale commercial applications.

A team of Northwestern University researchers has developed a new anode coating strategy that significantly enhances the efficiency of solar energy power conversion. A paper about the work, which focuses on engineering organic material-electrode interfaces in bulk-heterojunction organic solar cells, is published online this week in the Proceedings of the National Academy of Sciences (PNAS).

This breakthrough in solar energy conversion promises to bring researchers and developers worldwide closer to the goal of producing cheaper, more manufacturable and more easily implemented solar cells. Such technology would greatly reduce our dependence on burning fossil fuels for electricity production as well as reduce the combustion product: carbon dioxide, a global warming greenhouse gas.

Tobin J. Marks, the Vladimir N. Ipatieff Research Professor in Chemistry in the Weinberg College of Arts and Sciences and professor of materials science and engineering, and Robert Chang, professor of materials science and engineering in the McCormick School of Engineering and Applied Science, led the research team. Other Northwestern team members were researcher Bruce Buchholz and graduate students Michael D. Irwin and Alexander W. Hains.

Of the new solar energy conversion technologies on the horizon, solar cells fabricated from plastic-like organic materials are attractive because they could be printed cheaply and quickly by a process similar to printing a newspaper (roll-to-roll processing).

To date, the most successful type of plastic photovoltaic cell is called a bulk-heterojunction cell. This cell utilizes a layer consisting of a mixture of a semiconducting polymer (an electron donor) and a fullerene (an electron acceptor) sandwiched between two electrodes -- one a transparent electrically conducting electrode (the anode, which is usually a tin-doped indium oxide) and a metal (the cathode), such as aluminum.

When light enters through the transparent conducting electrode and strikes the light-absorbing polymer layer, electricity flows due to formation of pairs of electrons and holes that separate and move to the cathode and anode, respectively. These moving charges are the electrical current (photocurrent) generated by the cell and are collected by the two electrodes, assuming that each type of charge can readily traverse the interface between the polymer-fullerene active layer and the correct electrode to carry away the charge -- a significant challenge.

The Northwestern researchers employed a laser deposition technique that coats the anode with a very thin (5 to 10 nanometers thick) and smooth layer of nickel oxide. This material is an excellent conductor for extracting holes from the irradiated cell but, equally important, is an efficient blocker which prevents misdirected electrons from straying to the wrong electrode (the anode), which would compromise the cell energy conversion efficiency.

In contrast to earlier approaches for anode coating, the Northwestern nickel oxide coating is cheap, electrically homogeneous and non-corrosive. In the case of model bulk-heterojunction cells, the Northwestern team has increased the cell voltage by approximately 40 percent and the power conversion efficiency from approximately 3 to 4 percent to 5.2 to 5.6 percent.

The researchers currently are working on further tuning the anode coating technique for increased hole extraction and electron blocking efficiency and moving to production-scaling experiments on flexible substrates.


Contact: Megan Fellman
Northwestern University

Related biology technology :

1. Vion Pharmaceuticals Holds Special Meeting of Stockholders
2. Cell Therapeutics, Inc. (CTI) Shareholders Authorize Share Increase at Special Meeting of Shareholders
3. Advanced Medical Specialties Joins US Oncology Network
4. Special Stockholders Meeting to Elect Directors Set for March 4, 2008
5. Wedgewood Pharmacy Will Continue to Provide Avastin(R) to Ophthalmologists and Retinal Specialists
6. Georgia Reproductive Specialists is First in Southeast to Offer Pioneering Test of Womens Biological Clock
7. Agennix Receives Special Protocol Assessment Approval from FDA for the Pivotal Trial of Talactoferrin Alfa in First-Line Non-Small Cell Lung Cancer
8. ASH Holds a Special Symposium to Interest High School Students in Biomedical Research
9. ThromboGenics Presents Results of the Vitreomacular Traction Trial (MIVI IIT) at the American Society of Retina Specialists Annual Meeting
10. Delivering Molecular Imaging Solutions Across Clinical Specialties: Siemens Showcases New Technologies at RSNA 2007
11. Jennerex Appoints Bob Ingram Special Advisor and Hires Marty Glick as EVP, Corporate Strategy
Post Your Comments:
(Date:11/27/2015)... India , November 27, 2015 /PRNewswire/ ... --> Growing popularity of companion diagnostics ... in cancer biomarkers market with pharmaceutical companies ... in-demand companion diagnostic tests. ... --> Complete report on global cancer ...
(Date:11/25/2015)... 2 nouvelles études permettent d , identifier ... souches bactériennes retrouvées dans la plaque dentaire des ... Ces recherches  ouvrent une nouvelle voie ... l,un des problèmes de santé les plus fréquemm ... --> 2 nouvelles études permettent d , ...
(Date:11/25/2015)... ... November 25, 2015 , ... ... of Black Aerospace Professionals (OPBAP) has been formalized with the signing of a ... leaders met with OPBAP leaders Capt. Karl Minter and Capt. Albert Glenn Tuesday, ...
(Date:11/24/2015)... HILLS, N.J. (PRWEB) , ... November 24, 2015 , ... ... as the recipient of the 2016 USGA Green Section Award. Presented annually since 1961, ... golf through his or her work with turfgrass. , Clarke, of Iselin, ...
Breaking Biology Technology:
(Date:11/17/2015)... Paris from 17 th ... Paris from 17 th until 19 th ... leader, has invented the first combined scanner in the world ... scanning surface. Until now two different scanners were required: one ... both on the same surface. This innovation is an ...
(Date:11/16/2015)... , Nov 16, 2015  Synaptics Inc. ... human interface solutions, today announced expansion of its ... ™ touch controller and display driver integration ... of smartphones. These new TDDI products add to ... (HD resolution), TD4302 (WQHD resolution), and TD4322 (FHD ...
(Date:11/11/2015)... , Nov. 11, 2015   MedNet Solutions , ... spectrum of clinical research, is pleased to announce that it ... Clinical Trials (PCT) event, to be held November 17-19 ... able to view live demonstrations of iMedNet ... learn how iMedNet has been able to deliver ...
Breaking Biology News(10 mins):