Seminar - University of Massachusetts Lowell



Seminar - VI, Fall 2012

Advanced Electronic Technology Center

Pathway to ultra-efficient Photovoltaics : multijunction devices incorporating aperiodic dilute nitride quantum wells

Alex Freundlich

Center for Advanced Materials, University of Houston, Houston, Texas, USA

Following a short overview of the past heritage and the state of the recent developments in solar photovoltaics, the presentation will stress the criticality of high efficiency photovoltaics toward further balance of the system cost reductions and meeting the future terawatt scale needs in a cost effective manner. In this quest multijunction tandem devices operating in conjunction with high sunlight concentration have shown a strong promise and already have shown devices with efficiencies approaching or exceeding 40%. Previously we have shown that an alternate design, where dilute nitride quantum wells are inserted within the intrinsic region of a conventional GaAs p-i-n sub- cell could be used to overcome these limitations. Realization of such single junction device is shown to significantly improve the open circuit voltages compared to bulk-counterparts. In addition the increased electron effective masses and negligible valence band offset encountered in dilute nitrides provides a unique opportunity to exploit aperiodic quantum well designs that favor faster carrier escapes leading to devices with near ideal carrier collection efficiencies. The implementation of such designs is shown to provide a pathway toward the realization of ultra-efficient multi-junction devices with projected practical efficiencies approaching a staggering 50%.

Date: Monday, Nov 26th, 2012. Time: 3:30 pm;

Room: ECE Conference room (refreshments provided)

................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download