Abstract
We present recent improvements to the 4-junction inverted metamorphic solar cell. The device now includes a (Ga)InAsP buffer that transitions to lattice constants greater than InP, which allows access to GaInAs subcells with bandgaps < 0.74 eV and an additional 2 mA/cm2 of bottom junction photocurrent at AM1.5D. However, the optimal design depends on the spectrum and operating temperature. We show how the device flexibility can be used to fine-tune the design for various spectra in order to maximize energy yield for a given operating condition. 1-sun devices achieve 35.3% efficiency under the AM0 spectrum and 37.8% efficiency under the global spectrum at 25°C. Concentrator devices achieve 45.7% peak efficiency under 234x the direct spectrum and maintain over 45% efficiency at 700x at 25°C. Other device improvements include a 4-layer anti-reflection coating with low power loss, and reduced series resistance.
Original language | American English |
---|---|
Number of pages | 3 |
DOIs | |
State | Published - 14 Dec 2015 |
Event | 42nd IEEE Photovoltaic Specialist Conference, PVSC 2015 - New Orleans, United States Duration: 14 Jun 2015 → 19 Jun 2015 |
Conference
Conference | 42nd IEEE Photovoltaic Specialist Conference, PVSC 2015 |
---|---|
Country/Territory | United States |
City | New Orleans |
Period | 14/06/15 → 19/06/15 |
Bibliographical note
Extended version published in the IEEE Journal of Photovoltaics: see NREL/JA-5J00-66093NREL Publication Number
- NREL/CP-5J00-63574
Keywords
- 4-junction solar cells
- inverted metamorphic multijunction