Efficiency increase of organic solar cells with emissive light-in-coupling layersElectronic supplementary information (ESI) available: Spectral overlap of Alq3:DCM and ZnPc:C60; results of optical simulations for various layers and thicknesses; optical constants of Alq3 and Alq3:DCM. See DOI: 10.1039/c5tc02446c

Top-absorbing organic solar cells with a light incoupling layer allowing the exposure of harmful UV irradiation have been fabricated. Short-wavelength light is absorbed by the down-shifting system Alq 3 :DCM located in the light incoupling layer of top-absorbing organic solar cells and is converted into longer wavelengths. This red light is then absorbed by a ZnPc:C 60 bulk heterojunction solar cell, showing a total power efficiency increase by more than 10% related to additional photocurrent generated by this architectural concept. Top-absorbing organic solar cells with a light incoupling layer allowing the exposure of harmful UV irradiation have been fabricated.