929300 EQE external quantum efficiency 1558 1799909 EQEmax external quantum efficiency 189 2639996 EQEs external quantum efficiencies 166 2436082 etaext s external quantum efficiencies 5 2105974 eta ext external quantum efficiency 4 1901529 EQEEL external quantum efficiency 3 2216713 EQEmaxS external quantum efficiencies 3 3905658 EQEmax's external quantum efficiencies 1