Efficiency enhancement via metal-coated porous amorphous silicon back reflectors incorporated in amorphous silicon solar
- PDF / 1,584,775 Bytes
- 7 Pages / 612 x 792 pts (letter) Page_size
- 96 Downloads / 222 Views
lasmonics, Photonics, and Metamaterials Research Letter
Efficiency enhancement via metal-coated porous amorphous silicon back reflectors incorporated in amorphous silicon solar cells Shweta Bhandaru, Interdisciplinary Graduate Program in Material Science, Vanderbilt University, Nashville, TN 37235, USA Angelo Bozzola*, and Marco Liscidini, Department of Physics, University of Pavia, via Bassi 6, I-27100 Pavia, Italy Sharon M. Weiss, Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, TN 37235, USA Address all correspondence to S.M. Weiss at [email protected] and M. Liscidini at [email protected] (Received 18 January 2016; accepted 6 April 2016)
Abstract We present two straightforward and cost-effective methods, based on metal-assisted chemical etching and a direct imprinting technique, to fabricate metal-covered porous amorphous silicon back reflectors for amorphous silicon solar cells. We demonstrate an increase of approximately 30% in both short-circuit current and overall efficiency with respect to a cell with a flat metal back reflector. This is achieved by implementing light trapping via either a roughened porous amorphous silicon layer or an imprinted periodic grating. This work provides a pathway to increase amorphous silicon solar cell efficiency via increased absorption without significantly impacting processing costs.
Introduction Over the past few years, increasing demand for clean energy has resulted in several innovations, particularly in the field of photovoltaics. Research in solar cells ranging from exploration of new materials and morphologies to integration of photonic elements to improve light trapping has been constantly growing. Most photovoltaic studies can be broadly categorized into four areas: photon harvesting, photon absorption, photon-to-electron conversion, and extraction of photo-generated electrons. To maximize the amount of sunlight incident on a solar cell and improve photon harvesting, advances have been made in the development and implementation of concentrators[1] and trackers.[2] Incorporating anti-reflective coatings[3] as well as complex ordered, aperiodic, or random optical structures has led to improved absorption of photons incident on a solar cell.[4–7] More efficient photon-to-electron conversion in solar cells has been made possible by band gap engineering, including multi-junction cells in III–V[8] and II–VI[9] materials. To achieve more efficient extraction of photo-generated electrons from a solar cell into an external circuit, various materials including transparent conducting oxides have been studied and utilized as electrical contacts.[10,11] Despite these advances and a progressive increase in efficiency, with a recent III–V module reaching 43.4% efficiency,[12] solar cells account only for 1% of global electricity production.[13] Wide-scale adoption of many of the aforementioned advances into large-scale manufacturing has not occurred due to the expense of the materials or processing
techniques. Hence, there remains a
Data Loading...
