First demonstration of monolithic InP-based InAlAs/InGaAsP/InGaAs triple junction solar cells
Spectrolab has demonstrated the first lattice matched InAlAs/InGaAsP/InGaAs triple junction solar cell grown on InP substrate. X-ray diffraction characterization shows high quality solar cell materials. Preliminary 1-sun AM1.5D testing of the triple junction solar cell shows promising results with an open circuit voltage (V_(oc)) of 1.8V, a short-circuit current density (J_(sc)) of 11.0 mA/cm^2, a fill factor of 64.4%, and a 1-sun AM1.5D efficiency of 13.8%. The same cell also passes 27-suns under concentration. Improvements in layer design and crystal quality of advanced features can further raise the 1-sun and concentrated AM1.5D conversion efficiency of the InP-based triple junction cell beyond 20%.