Universidad Politécnica de Madrid

Instituto de energía solar

R&D at IES

Concentrator solar cells


Concentrator solar cells are the core of concentrator photovoltaic systems. We have been working on this field since 1987 and we have achieved as main results: a) a single junction GaAs solar cell with an efficiency of 26.2% at 1000 suns in 1999; b) a dual junction GaInP/GaAs with an efficiency of 32.6% at 1026 suns in 2008 which was world record and c) a triple junction GaInP/GaInAs/Ge cell with an efficiency of 40% at 400 suns in 2014. In the development of concentrator solar cells (see figure 1) we follow the “LED-like approach” (that we proposed in 2000) which looks to the small sizes and optoelectronic techniques used in LEDs (Light Emitting Diodes)

The efficiency increase from the 40% level requires the use of more than three subcells. This is why we are developing solar cells with four, five and six junctions. Metamorphic, lattice-matched dilute nitride and wafer bonding architectures are being investigated. Our goal is to reach 50% efficient solar cells. We work on the whole value chain of the concentrator solar cell, namely, modeling & simulation, MOVPE growth, material and device characterization, reliability and cost analysis.


Contact person: Prof. Carlos Algora

Selected publications

  1. C. Algora, E. Ortiz, I. Rey-Stolle, V. Díaz, R. Peña, V. Andreev, V. Khvostikov and V. Rumyantsev., “A GaAs solar cell with an efficiency of 26.2% at 1000 suns and 25.0% at 2000 suns”, IEEE Transactions on Electron Devices 48 (5), pp: 840-844 (2001)

  2. I. García, I. Rey-Stolle, B. Galiana, and C. Algora, “A 32.6% efficient lattice-matched dual-junction solar cell working at 1000 suns ”, Applied Physics Letters 94, Vol 5, pp: 053509 (2009). http://dx.doi.org/10.1063/1.3078817

  3. E. Barrigón, I. García, L. Barrutia, I. Rey‐Stolle, C. Algora, “Highly conductive p ‐AlGaAs/n ‐GaInP tunnel junctions for ultra‐high concentrator solar cells”, Progress in Photovoltaics 22, Vol. 4, pp. 399–404 (2014) (DOI: 10.1002/pip.2476)

  4. C Algora, I Rey-Stolle, B Galiana, JR González, M Baudrit, I García, "Strategic Options for a LED-Like Approach in III-V Concentrator Photovoltaics”, in Conference Record of the 2006 IEEE 4th World Conference on Photovoltaic Energy Conversion, 2006 Hawaii, pp. 741-744. DOI:10.1109/WCPEC.2006.279562


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