Fig. 4: Photomultiplication in the CT region and used in narrowband devices.

a EQE as a function of excitation wavelength for the broadband photodetector. Red dashed line shows the EQE spectrum of a conventional ZnPc:C₆₀ (50 wt%) photodiode and the black solid line the PM-OPD, both at 0 V. Solid lines show the spectra of the PM-OPD (3 wt% C₆₀) under bias as indicated in the legend. Under −5 V, the higher injection provided by the energy level bending leads to an EQE higher that of a conventional pin-photodiode. b JV characteristics under dark and under 100 mW cm⁻² of four different narrowband devices with varying resonant wavelength as indicated in the legend. c EQE of cavities of the same devices shown in b at −10 V. As the active layer thickness increases from 355 to 400 nm, the resonant wavelength redshifts from around 830 to 880 nm. Dashed lines show the fit to a Lorentzian function, from which the FWHM is extracted. d EQE measured at different voltages is fitted with polynomial function, from which D* is predicted. An optimum operation region is found around −3.5 V, where D^* of 6 × 10¹¹ Jones is obtained.