Tuning spectral selectivity in microcavity organic photodetectors via absorption management

Microcavity organic photodetectors (OPDs) utilize optical resonance to achieve wavelength-selective photodetection. Tailoring their spectral response requires understanding the interplay between cavity resonance and intrinsic material absorption. This work systematically controls microcavity resonance through layer thickness modulation and material selection to investigate its influence on spectral response. It demonstrates that employing a thick, strongly absorbing functional layer suppresses wide-angle and multibeam interference effects, thereby inhibiting spectral tunability. Cavity resonance tuning—essential for tailored spectral response—is only achievable by adjusting the cavity length via thickness control of a weakly absorbing functional layer, which facilitates interference between the two reflective electrodes. These results highlight the critical role of absorption management in microcavity OPD design and establish a systematic framework for optimizing spectral response through balanced cavity engineering and absorption control.