High External Quantum Efficiency and Ultra‐Narrowband Organic Photodiodes Using Single‐Component Photoabsorber With Multiple‐Resonance Effect

Abstract Organic photodiodes (OPDs) that utilize wavelength‐selective absorbing molecules offer a direct approach to capturing specific wavelengths of light in multispectral sensors/imaging systems without filters. However, they exhibit broad response bandwidths, low external quantum efficiency ( EQE ), and often require compromises in two‐component photoactive materials. Herein, the first utility of boron‐nitrogen (BN) single‐component photoabsorbers, leveraging a multi‐resonance effect are introduced to attain OPDs with both record‐high EQE of 33.77% and ultra‐small full‐width half‐maximum ( FWHM ) of 36 nm in the reported narrowband OPDs using single‐component photoabsorbers. It is found that the outstanding performance of these narrowband OPDs can be attributed to the ultra‐small FWHM , slow charge recombination, low activation energy, and balanced bipolar charge transport within the para ‐tert‐butyl substituted B,N‐embedded rigid polycyclic molecule (BNCz) film. Furthermore, BN derivatives such as BN( p )SCH 3 , BN( p )SO 2 CH 3 , and pyBN‐ m ‐H have also shown high EQE , minimal FWHM , and tunable photoresponse peaks ranging from blue‐violet to blue‐turquoise, highlighting the potential of BN molecules and molecular engineering in the development of novel narrowband absorbers for advanced wavelength‐selective OPDs. Such pioneering working can provide a class of novel narrowband absorbers to propel the advancement of high‐performance wavelength‐selective OPDs.